Step cleaning method for swimming pool robot and swimming pool robot

Abstract

The invention provides a step cleaning method for a swimming pool robot and the swimming pool robot, and relates to the technical field of swimming pool robots. An underwater suspension module is arranged on the swimming pool robot, and the method comprises the steps that the swimming pool robot can be switched between step surfaces through the underwater suspension module without depending on adsorption support on the step surfaces, and posture position adjustment is completed in a suspension state; the underwater suspension module has a buffering effect in the falling process, so that the falling process is more stable, the inclination or slippage risk caused by the width change of the step is reduced, and the continuity of the step area cleaning process is ensured; after falling, the underwater suspension module can continuously provide vertical pressure, so that the swimming pool robot is stably attached to the surface of the step and performs cleaning operation; by controlling the ratio of the diameter of the mounting hole to the rotating speed of the rotor wings, the turbulent flow effect generated when the underwater suspension module is started when the swimming pool robot gets close to the steps is reduced, and the posture stability and the cleaning effect in the step crossing process are improved.

Description

RELATED APPLICATION

[0001] The present disclosure is based on a patent application No.PCT / CN2025 / 107421, filed on July 7, 2025, entitled“Swimming pool robot and swimming pool cleaning device”, and claims priority to the patent application, the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure relates to the technical field of swimming pool robots, in particular, to a step cleaning method for a swimming pool robot and a swimming pool robot. BACKGROUND

[0003] With the increasing demand for swimming pool maintenance, swimming pool robots are widely used in household and commercial scenarios. The current swimming pool robots can generally perform autonomous driving on flat pool bottoms or pool wall surfaces, and complete daily cleaning tasks through components such as dirt suction and brushing. However, for swimming pool areas with step structures, due to the characteristics of multiple levels of height difference, different widths of water flat surfaces, and complex edge profiles, the conventional cleaning path and movement mode are difficult to directly adapt to the cleaning needs of the step area.

[0004] Currently, the swimming pool robot mainly uses the climbing method for cleaning the step area. This method not only has low cleaning coverage, but also has the problems of cleaning omission of the step surface and insufficient cleaning of the step edge.

[0005] It should be noted that the information disclosed in the above background section is only used to strengthen the understanding of the background of the present disclosure, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0006] The purpose of the embodiments of the present disclosure is to provide a step cleaning method for a swimming pool robot and a swimming pool robot, thereby improving the cleaning coverage of the step surface and improving the cleaning effect of the step surface.

[0007] Other characteristics and advantages of the present disclosure will become apparent from the following detailed description, or will be learned by practice of the present disclosure.

[0008] According to a first aspect of the embodiments of the present disclosure, a step cleaning method for a swimming pool robot is provided, the swimming pool robot comprising an underwater suspended module, the method comprising: suspending the swimming pool robot to fall on a first step surface of the step by the underwater suspended module and cleaning the step; The underwater suspension module is arranged in the mounting hole arranged on the pool robot body, and the ratio of the diameter of the mounting hole to the rotating speed of the rotor of the underwater suspension module is 0.0133 mm / (r / min)-0.08 mm / (r / min) during the process that the pool robot is suspended and falls on the first step surface.

[0009] On the one hand, by arranging the underwater suspension module on the pool robot for generating controllable thrust under water, the pool robot can switch between steps without relying on the adsorption contact support of the step surface, and can complete the attitude adjustment and approach to each step surface in the suspended state, so that the pool robot has a relatively stable and controllable cleaning attitude when reaching the step surface to be cleaned, improves the cleaning coverage of the step surface, and avoids the problems of cleaning omission of the step surface and insufficient cleaning of the step edge. On the other hand, when the pool robot approaches the step surface in the suspended state, the controllable suspension thrust output buffers the falling process of the body, so that the pool robot is more inclined to gradually fall in a stable manner during the contact with the step surface, reduces the problem of instantaneous tilting or sliding of the body caused by the small width of the step or the sudden change of the support boundary, and solves the problem of unstable falling attitude of the pool robot in the step area caused by relying on adsorption support, which further affects the continuity of step cleaning. After falling, the underwater suspension module can still provide a continuously adjustable vertical pressure, so that the force on the pool robot on the step surface is more stable, thereby enhancing the adhesion and retention ability of the pool robot on the step surface and improving the stability of the pool robot in walking and cleaning on the step area. On the other hand, by keeping the matching range of the diameter of the mounting hole and the rotating speed of the rotor of the underwater suspension module at 0.0133 mm / (r / min)-0.08 mm / (r / min), the rotor of the underwater suspension module can generate a relatively stable and soft flow field distribution around the body in the narrow space between steps, thereby reducing the turbulence generated by the underwater suspension module during operation, enabling the pool robot to realize stable suspension movement in water, further improving the attitude stability of the pool robot during step cleaning, and thereby improving the cleaning coverage of the step surface and improving the cleaning effect of the step surface.

[0010] In some example embodiments of the present disclosure, based on the foregoing scheme, the pool robot is suspended on the first step surface of the step by the underwater suspension module, comprising: The pool robot is in a suspended state by the activated underwater suspension module; The suspension thrust of the underwater suspension module is controlled to make the pool robot in the suspended state have a target roll angle, and drive the pool robot in the target roll angle to move laterally and approach the first step surface. detecting completion of approaching the first step surface, and controlling the pool robot to land on the first step surface.

[0011] By adjusting the suspension thrust of the underwater suspension module in the suspended state to form a target roll angle, the pool robot can approach the first step surface in a stable posture during lateral movement, thereby reducing posture deviation of the body caused by water disturbance or irregular step boundary; and after reaching the approaching position, the pool robot is landed, so that the landing action is based on the adjusted posture, thereby improving landing accuracy and avoiding the problems of approaching deviation and inaccurate cleaning starting position caused by the traditional contact crawling mode.

[0012] In some example embodiments of the present disclosure, based on the foregoing scheme, the pool robot is controlled to land on the first step surface, including: When the pool robot moves to above the first step surface in the target roll angle, the suspension thrust of the underwater suspension module is adjusted to switch the posture of the pool robot from the target roll angle to a horizontal posture, and the pool robot in the horizontal posture is controlled to land on the first step surface; or When the pool robot moves to above the first step surface in the target roll angle, the suspension thrust of the underwater suspension module is adjusted to make the other side land on the first step surface after the one side of the pool robot in the target roll angle lands on the first step surface.

[0013] By completing smooth switching from the target roll angle to the horizontal posture using the suspension thrust above the first step surface, or by first contacting the step from the inside and then landing on the other side in stages, the landing mode under different step widths can obtain sufficient stress support area, thereby effectively reducing the risk of instantaneous tilting and sliding during landing on the narrow step or across the step, making the landing action a process of gradually establishing stable support, improving the controllability and reliability of step landing, and improving the accuracy of the position of the pool robot landing on the step surface, thereby improving the cleaning coverage rate of the step surface and ensuring the cleaning effect.

[0014] In some example embodiments of the present disclosure, based on the foregoing scheme, the pool robot includes a lateral driving module, and the direction of the lateral thrust generated by the lateral driving module and the direction of the suspension thrust generated by the underwater suspension module form a preset angle. The pool robot is suspended and landed on the first step surface of the step by the underwater suspension module, including: The pool robot is in a suspended state by the activated underwater suspension module; When the pool robot in the suspended state reaches the target position, the pool robot is translated to approach the first step surface by the activated lateral driving module; When the approach to the first step surface is detected to be completed, the pool robot is controlled to land on the first step surface.

[0015] By making the thrust direction of the lateral driving module and the underwater suspension module have a preset angle, the pool robot can be laterally translated in the suspended state without relying on the contact support of the pool bottom or the step surface, so that more flexible posture adjustment capability is obtained in the narrow geometric environment of the step area, and the suspended approach with lateral compensation capability can reduce the deviation caused by relying only on longitudinal propulsion and suspension thrust, so that the pool robot can still maintain stable approach and accurate positioning at the complex step edge, thereby improving the stability and reliability of the pool robot when moving between multiple steps.

[0016] In some example embodiments of the present disclosure, based on the foregoing scheme, the pool robot is controlled to land on the first step surface, including: When the width of the first step surface is greater than or equal to the body width of the pool robot, the pool robot is driven by the underwater suspension module to be suspended above the first step surface, and the projection area of the pool robot on the first step surface is entirely within the first step surface, at which time the pool robot is controlled to land on the first step surface.

[0017] By suspending the pool robot above the step surface and ensuring that the projection area is completely within the step range when the width of the first step surface is not less than the body width, the landing action of the pool robot can be performed on the step surface area with complete support surface, so that the body inclination caused by force bias during landing can be avoided, and the landing process is more stable; After landing, the pool robot obtains uniform support torque on the step surface, so that subsequent cleaning trajectory execution is more stable and continuous, cleaning omission caused by body shaking is reduced, and the cleaning coverage of the step surface is improved.

[0018] In some example embodiments of the present disclosure, based on the foregoing scheme, the pool robot is controlled to land on the first step surface, including: When the width of the first step surface is less than the body width of the pool robot, the pool robot is driven by the underwater suspension module to be suspended above the first step surface, and the projection area of the pool robot on the first step surface covers the entire width range of the first step surface, at which time the pool robot is controlled to land on the first step surface.

[0019] By suspending and positioning the robot directly above the step even when the step width is smaller than the robot's body width, and ensuring that the projection area covers the entire step width, the robot's body lands on the step as much as possible. This allows the robot to achieve a controllable landing state even when partially suspended, thanks to its levitation thrust. This avoids situations where the robot cannot enter the cleaning area due to insufficient step area. This preset projection coverage landing mode enables the robot to land even in narrow step areas, enhancing its cleaning capabilities in complex step scenarios and improving its cleaning coverage and effectiveness in multi-level complex step scenarios.

[0020] In some exemplary embodiments of this disclosure, based on the foregoing scheme, controlling the pool robot to land on the first step surface includes: Adjust the levitation thrust of the underwater suspension module so that the pool robot approaches the first step surface at the target roll angle. At this time, the body of the pool robot that is close to the inside of the first step surface lands on the first step surface first. The inner side of the first step surface is the side away from the side of the pool robot that is suspended on the first step surface.

[0021] By adjusting the suspension thrust, the pool robot approaches the inside of the step at the target roll angle, prioritizing the establishment of an inner support point during landing. Then, it gradually lands on the suspended side using a slow descent method, significantly reducing the risk of tipping over and slipping on narrow steps due to a single landing. This phased landing mechanism enables the pool robot to form a stable support combination on steps with insufficient width, ensuring the continuity and stability of the cleaning action.

[0022] In some exemplary embodiments of this disclosure, based on the foregoing scheme, before suspending the pool robot via the underwater levitation module and placing it on the first step surface of the step, the method further includes: Obtain the location information of the steps and the global cleaning path of the steps; The pool robot is driven to the starting point of the steps based on the global cleaning path. The starting point is located at one end of the step area near the top or bottom step.

[0023] By acquiring step location information and global cleaning paths in advance, the pool robot establishes an environmental awareness of the step hierarchy and entry direction before entering the step area. This avoids path deviations caused by blindly approaching the step area. This guided entry based on global paths enables the hovering and landing actions to be performed at the correct step entrance, improving the planning completeness and path consistency of cross-step cleaning tasks, making the coverage of the step area more comprehensive, thereby improving the cleaning coverage of the pool robot on the step area and enhancing the cleaning effect of the step area.

[0024] In some exemplary embodiments of this disclosure, based on the foregoing scheme, the underwater levitation module suspends the pool robot and places it on the first step surface of the step, including: When the starting point is located at the end closest to the top step, the step surface of the top step is the first step surface. The underwater levitation module causes the pool robot to levitate downwards and land at the starting position of the first step surface of the step. When the starting point is located at the end closest to the bottom step, the step surface of the bottom step is the first step surface. The underwater levitation module causes the pool robot to levitate upward and land at the starting position of the first step surface of the step. Specifically, when the pool robot is suspended downwards, the levitation thrust of the underwater levitation module is less than the levitation thrust when it is suspended upwards.

[0025] By selecting between downward or upward levitation based on the level of the step, the pool robot can step onto the target step surface in the correct direction. Different thrust levels are used to differentiate the power requirements between the upper and lower steps, allowing the pool robot to maintain stable momentum during step-crossing displacement. This reduces abrupt attitude changes caused by different directions of the steps. This directional adaptive levitation landing method improves the spatial accuracy of the pool robot entering the step area, making the landing starting point more consistent with the cleaning trajectory plan and improving the cleaning efficiency of the step area.

[0026] In some example embodiments of this disclosure, based on the foregoing scheme, the method further includes: Obtain the step contour information of the first step surface; The local cleaning path of the pool robot on the first step surface is planned based on the step contour information; The local cleaning path includes the starting and ending positions of the cleaning path of the pool robot on the first step surface, with the starting position being the position where the pool robot suspends and first lands on the first step surface.

[0027] By acquiring the contour information of the first step surface and generating a local cleaning path that matches the geometric features, the cleaning trajectory can conform to the actual shape of the step, thus avoiding insufficient edge cleaning and corner cleaning omissions caused by fixed path patterns. By using the initial floating landing point as the cleaning start point, the cleaning action starts from the precisely positioned landing position, achieving path continuity and improving the depth cleaning capability of the step. Furthermore, by establishing a binding relationship between the floating landing position and the starting position of the local cleaning path, a natural connection from the floating landing to the cleaning movement is achieved on the first step surface, avoiding unnecessary posture adjustments and displacement movements introduced due to the inconsistency between the starting position and the landing position. This reduces the posture instability and fall risk caused by repeated starts, stops, and turns in the narrow area of ​​the step, making the local cleaning process of the first step surface more continuous and controllable, and improving the cleaning coverage of the step surface.

[0028] In some example embodiments of this disclosure, based on the foregoing scheme, the method further includes: When the first step surface is cleaned, if a second step surface that has not been cleaned is detected, the end point of the cleaning process on the first step surface is taken as the new starting point. The new starting point is the starting point for cleaning the uncleaned area on the step. The pool robot is then suspended and landed on the starting point of the second step surface by the underwater suspension module.

[0029] By using the cleaning endpoint as the new starting point after the first step surface is cleaned, the cross-step cleaning process does not require repositioning, thus avoiding cleaning interruptions caused by repeatedly approaching or searching for the starting point again, improving cleaning continuity, and reducing cleaning blind spots; then the underwater suspension module performs cross-step suspension and landing, so that the transition from one step cleaning area to the next step cleaning area remains continuous, improving the coherence and cleaning coverage of the overall step sequence cleaning.

[0030] In some example embodiments of this disclosure, based on the foregoing scheme, the method further includes: If the pool robot is detected to have fallen off the first step, it will be driven back to the starting point corresponding to the first step, which is the starting position for cleaning the uncleaned area on the step. After the pool robot is suspended by the underwater levitation module and lands at the starting position of the first step, it will continue to perform the cleaning task of the first step.

[0031] By automatically returning to the starting point of the corresponding step and re-suspending after detecting a fall, the pool robot possesses fall recovery capability, thereby avoiding cleaning gaps and path interruptions caused by falls. This automatic return and re-suspension process allows the pool robot to quickly return to the cleaning task chain, ensuring the complete execution of the step cleaning task and improving the reliability and fault tolerance of operations in the step area. Furthermore, by returning to the starting point to continue the previous cleaning task, the risk of path errors or collisions that may occur when the pool robot replans its recovery path can be effectively avoided, improving the reliability and accuracy of cleaning task execution.

[0032] In some example embodiments of this disclosure, based on the foregoing scheme, the method further includes: If the pool robot is detected to have fallen from the first step, the underwater levitation module will cause the pool robot to levitate back to its original position before the fall, and then continue to perform the cleaning task on the first step after returning to the original position.

[0033] By directly returning to its original position before the fall based on the detected position information, the pool robot can resume its previous cleaning trajectory without altering its original cleaning path, thus avoiding missed cleaning sections or deviations in cleaning progress caused by the fall. The floating return method using the pre-fall position information allows the pool robot to quickly realign with its original cleaning path, ensuring continuous cleaning and improving the stability and consistency of the work process in the stepped area. By directly returning to its original position without needing to reposition itself at the step entrance, the recovery time after the fall is significantly reduced, allowing the pool robot to more quickly re-engage in the cleaning process of the area to be cleaned, thereby improving the overall efficiency of cleaning tasks in the stepped area.

[0034] According to a second aspect of the present disclosure, a pool robot is provided, comprising: The robot itself; The propulsion drive module is located on both sides of the robot body and is used to drive the robot body to move forward. An underwater levitation module is installed on the robot body to provide underwater levitation thrust to the robot body so that the pool robot is in a levitation state and to control the attitude of the pool robot in the levitation state. A control module, located inside the robot body, is used to perform the cleaning method for the pool robot as described in the first aspect.

[0035] In some exemplary embodiments of this disclosure, based on the foregoing scheme, the pool robot further includes: A lateral drive module is mounted on the robot body, and the lateral thrust generated by the lateral drive module is at a preset angle to the levitation thrust generated by the underwater levitation module.

[0036] By incorporating the lateral drive module, the pool robot gains direct control over lateral displacement during step cleaning tasks. When hovering between multiple steps, the lateral drive module helps the robot translate towards the target step surface with less disturbance, making the landing process more stable. In complex step contours or curved surfaces, the lateral drive module can provide auxiliary attitude correction, making the thrust adjustment process of the underwater suspension module more precise, thereby improving the robot's overall controllability and cleaning continuity in the step area.

[0037] In some exemplary embodiments of this disclosure, based on the foregoing scheme, the pool robot includes at least two underwater levitation modules, which are symmetrically arranged on both sides of the body along the forward direction of the pool robot; or The pool robot includes four underwater levitation modules, with every two underwater levitation modules symmetrically arranged on both sides of the body along the direction of the pool robot's movement.

[0038] By employing multiple or four underwater levitation modules, the pool robot achieves greater attitude stability, stronger anti-disturbance capabilities, and more flexible landing control in stepped areas. Multiple underwater levitation modules provide precise thrust compensation under complex conditions such as water disturbance, irregular step shapes, insufficient step width, or partial robot suspension, enabling the pool robot to achieve stable hovering approach, hovering movement, and hovering landing in confined spaces. This significantly improves its adaptability and controllability when performing cleaning tasks in stepped areas. Simultaneously, the four-module layout, while maintaining the manufacturing cost of the pool robot, further enhances the redundancy and accuracy of three-dimensional attitude control, giving the pool robot higher reliability and cleaning coverage when traversing multiple steps or handling complex step surfaces.

[0039] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0040] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0041] Figure 1The illustration shows a schematic flowchart of a step cleaning method for a pool robot according to some embodiments of the present disclosure.

[0042] Figure 2 The schematic diagram illustrates the path of a pool robot levitating onto a first step surface via an underwater levitation module, according to some embodiments of the present disclosure.

[0043] Figure 3 The illustration schematically shows a swimming pool robot, according to some embodiments of the present disclosure, hovering in a horizontal posture on a first step surface.

[0044] Figure 4 The illustration schematically shows a swimming pool robot, according to some embodiments of the present disclosure, hovering on a first step surface with a target roll angle.

[0045] Figure 5 The illustration shows a scenario in which the width of the body of a pool robot according to some embodiments of the present disclosure is less than the width of the first step surface.

[0046] Figure 6 The illustration shows a scenario in which the width of the body of a pool robot according to some embodiments of the present disclosure is greater than the width of the first step surface.

[0047] Figure 7 The schematic diagram illustrates the path of a pool robot levitating onto a first step surface via an underwater levitation module, according to other embodiments of the present disclosure.

[0048] Figure 8 The schematic diagram illustrates a process flow diagram of a step cleaning method for a pool robot according to some other embodiments of the present disclosure.

[0049] Figure 9 The illustration schematically shows the working principle of the underwater levitation module when the pool robot is at least partially suspended in the air according to some embodiments of the present disclosure.

[0050] Figure 10 The illustration schematically shows the working principle of the underwater levitation module when a pool robot tilts unexpectedly according to some embodiments of the present disclosure.

[0051] Figure 11 The illustration schematically shows a working principle of a pool robot whose posture is stabilized by a lateral drive module according to some embodiments of the present disclosure.

[0052] Figure 12 The schematic diagram illustrates a process flow diagram of a step cleaning method for a pool robot according to some further embodiments of the present disclosure.

[0053] Figure 13The illustration schematically shows the working principle of the underwater levitation module when the pool robot is at least partially suspended in the air according to some other embodiments of the present disclosure.

[0054] Figure 14 A schematic diagram illustrating the composition of a pool robot according to some embodiments of the present disclosure is shown.

[0055] Figure 15 The illustration shows a schematic diagram of a pool robot with two underwater levitation modules according to some embodiments of the present disclosure.

[0056] Figure 16 The schematic diagram illustrates a structure of a pool robot with four underwater levitation modules according to some embodiments of the present disclosure.

[0057] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts. Detailed Implementation

[0058] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this specification. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this specification as detailed in the appended claims.

[0059] The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of this specification. The singular forms “a,” “the,” and “the” as used in this specification and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0060] It should be understood that although the terms first, second, third, etc., may be used in this specification to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this specification, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0061] Furthermore, the accompanying drawings are for illustrative purposes only and are not necessarily drawn to scale. The block diagrams shown in the drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0062] Currently, most pool robots clean stepped areas by climbing. However, pool steps can have significant height differences or limited effective support widths. For example, when the step height varies considerably relative to the pool floor, traditional self-propelled climbing robots often cannot smoothly cross the front boundary of the step. This can lead to situations where the front wheels or front drive structure are suspended in the air, or the drive wheels spin freely, preventing them from entering the target step surface and leaving that area uncleanable. Similarly, when the effective support width of the step is narrow, traditional pool robots attempting to enter the step may not have their entire projection area within the step surface, leaving parts of the structure suspended. This can cause the robot to shift its posture, become unstable, or lose adhesion, ultimately preventing it from entering the step surface to perform cleaning operations. Alternatively, the robot's climbing posture may become unstable, leading to tilting, slipping, or falling off the step surface, thus affecting cleaning continuity and the effectiveness of the step cleaning.

[0063] Based on one or more problems existing in the related technologies, this disclosure first provides a step cleaning method for a swimming pool robot. This step cleaning method for a swimming pool robot can be applied to a swimming pool robot or a server. This embodiment does not make any special limitations on it. The following description will take the execution of this method by a swimming pool robot as an example. Figure 1 The schematic diagram illustrates a process flow of a step cleaning method for a pool robot according to some embodiments of the present disclosure. Reference Figure 1 As shown, the step cleaning method for a pool robot may include the following steps: Step S110: The underwater levitation module suspends the pool robot on the first step surface of the step and cleans the step; wherein, the underwater levitation module is disposed in the mounting hole provided in the body of the pool robot, and during the process of the pool robot levitling on the first step surface, the ratio of the diameter of the mounting hole to the rotor speed of the underwater levitation module is 0.0133mm / (r / min)-0.08mm / (r / min).

[0064] According to the step cleaning method for a swimming pool robot in this example embodiment, on the one hand, by setting an underwater levitation module on the swimming pool robot to generate controllable thrust underwater, the swimming pool robot can switch between steps without relying on the adsorption contact support of the step surface. It can also complete attitude adjustment and approach each step surface while in a levitation state. This allows the swimming pool robot to have a relatively stable and controllable cleaning posture when it reaches the step surface to be cleaned, improving the cleaning coverage of the step surface and avoiding problems such as missed cleaning of the step surface or insufficient cleaning of the step edges. On the other hand, when the swimming pool robot approaches the step surface in a levitation state, the controllable levitation thrust output buffers the descent process of the robot body, making the swimming pool robot more inclined to land smoothly and gradually during contact with the step surface. This reduces the problem of instantaneous tilting or slippage of the robot body caused by the small step width or abrupt change in support boundary, thereby solving the problem of the swimming pool robot's landing in the step area due to reliance on adsorption support. The underwater levitation module addresses the issues of unstable posture, susceptibility to falls, and disruption of the cleaning continuity on steps. After positioning, it provides continuous and adjustable vertical pressure, stabilizing the robot's force on the step surface and enhancing its adhesion and retention capabilities. This improves the stability of the robot's movement and cleaning actions on steps. Furthermore, by maintaining a matching range between the mounting hole diameter and the rotor speed of the underwater levitation module (0.0133 mm / (r / min) - 0.08 mm / (r / min), the water flow generated by the rotor in narrow areas such as between steps can form a relatively stable and gentle flow field around the robot. This reduces turbulence generated during operation, enabling the robot to achieve stable levitation and further improving its posture stability when cleaning across steps. Ultimately, this increases the cleaning coverage and effectiveness of the step surface.

[0065] The step cleaning method for a pool robot in this example embodiment will be further described below.

[0066] In step S110, the underwater levitation module causes the pool robot to levitate and land on the first step surface of the step, and clean the step. The underwater levitation module is disposed in a mounting hole provided in the body of the pool robot. During the process of the pool robot levitling and landing on the first step surface, the ratio of the diameter of the mounting hole to the rotor speed of the underwater levitation module is 0.0133 mm / (r / min) - 0.08 mm / (r / min).

[0067] The underwater levitation module refers to a power component that generates directional fluid thrust in water to achieve lifting, lowering, and attitude control of a pool robot. It can provide a reverse water flow acting in the direction of the pool robot's movement, thereby enabling the pool robot to levitate, float, or sink in the water. In an optional embodiment, the underwater levitation module can consist of an electric drive unit, a rotor assembly, and a jet guide structure. The electric drive unit can be a brushless direct current motor (BLDC) to achieve precise thrust adjustment through high-response speed control. The rotor assembly can be located at the motor output end to drive the water flow to form a directional jet. The jet guide structure can be a cylindrical, conical, or streamlined guide shroud to reduce flow resistance and improve the stability of the jet direction. The number of underwater levitation modules can be determined based on the relevant parameters of the pool robot. For example, there can be one underwater levitation module, located in the center of the pool robot; there can also be two underwater levitation modules, symmetrically distributed on both sides of the pool robot along the axis, or symmetrically distributed along the center of the pool robot; there can also be four underwater levitation modules, symmetrically distributed on the pool robot in pairs. This example embodiment does not impose any special limitations on the number of underwater levitation modules or their distribution on the pool robot.

[0068] Mounting holes are pre-drilled cavities or mounting channels on the main body of a pool robot that match the underwater levitation module. By rationally designing the ratio between the diameter of the mounting hole and the rotor size of the underwater levitation module, the levitation thrust can be directed near the center of the pool robot, thereby reducing the risk of attitude deflection. The mounting holes can be integrally formed into the body shell using injection molding or CNC machining. Their inner walls are typically coated with a waterproof insulating layer to prevent motor wires and connectors from contacting the water. The underwater levitation module can be installed in these mounting holes.

[0069] After the underwater levitation module is activated, its rotors generate a directional water flow. The reaction force of the reverse water flow acts on the pool robot's body, causing it to generate a vertical upward or downward levitation thrust. By controlling the rotor speed, the thrust can be adjusted to allow the pool robot to achieve buoyancy balance in the water. For example, when the levitation thrust of the underwater levitation module is approximately equal to the pool robot's current weight (i.e., the weight obtained after the cancellation of its own weight and buoyancy), the pool robot enters a static levitation state; when the levitation thrust is less than the pool robot's current weight, the pool robot slowly sinks; when the levitation thrust is greater than the pool robot's current weight, the pool robot slowly rises. By continuously controlling the rotor speed, the pool robot can approach the target step surface at a stable speed, forming a levitation landing path to the designated position. (Reference)Figure 2 As shown, when the pool robot 210 arrives at the starting point A of the step area 220, it can be driven to float and rise by activating the underwater levitation module 211. After reaching the target rising height, it floats and lands on the starting position B of the first step surface 221 along the path AB, thus realizing the floating landing of the pool robot towards the first step surface.

[0070] During the levitation and landing process, the ratio between the diameter of the mounting hole and the rotor speed can be maintained within the range of 0.0133 mm / (r / min) to 0.08 mm / (r / min). This ratio is determined based on the comprehensive matching relationship between the water flow rate, flow velocity and jet diffusion angle generated by the rotor of the underwater levitation module. For example, the ratio can be 0.0133 mm / (r / min), 0.015 mm / (r / min), 0.02 mm / (r / min), 0.04 mm / (r / min), 0.07 mm / (r / min) or 0.08 mm / (r / min). The specific ratio can be automatically selected and determined based on the water density of the pool in the actual scenario, the gravity and buoyancy of the pool robot in the pool, or the test results of the levitation thrust of the pool robot in the pool, etc., or it can be calibrated at the factory based on actual experimental data. This embodiment does not impose any special limitations on this. When the ratio is too small, the jet stream is concentrated and the flow velocity is too high, which can easily generate strong turbulence at the bottom of the pool robot's body, especially in multi-step scenarios, causing the pool robot's posture to shake or generating reverse suction from the water flow. When the ratio is too large, the jet stream is dispersed and the thrust is insufficient, failing to provide effective levitation thrust. By controlling the ratio within the above range, it is possible to ensure that the pool robot generates sufficient levitation thrust while making the water flow distribution more uniform and gentle, reducing the impact of turbulence on the pool robot. Especially between steps in multi-step areas, it can significantly reduce the body posture disturbance caused by fluid vortices, allowing the pool robot to maintain balanced and stable levitation motion. Furthermore, the control of jet disturbance is not only related to the posture stability of the pool robot itself, but also directly affects the flow direction of impurities in the cleaning area. For example, during the cleaning process of steps, if the jet stream generated by the underwater levitation module is too concentrated or the turbulence intensity is too high, it may engulf small impurities located on the surface or edge of the steps into the water and disturb them along the water flow direction to the already cleaned pool bottom area, causing secondary pollution and affecting the cleaning quality of the cleaned area. By limiting the ratio of the mounting hole diameter to the rotor speed within the above range, the jet exhibits a relatively uniform and low-impact flow field when it contacts the step area. This effectively reduces disturbance to the deposits on the step surface, prevents impurities from being washed into the cleaned area, and maintains the cleanliness of the cleaned area, thus improving the continuity and quality of the overall cleaning process.

[0071] When the pool robot switches between underwater multi-level steps, the ratio between the diameter of the mounting hole and the rotor speed of the jet generated by the underwater levitation module is maintained within the range of 0.0133 mm / (r / min) to 0.08 mm / (r / min). This creates a relatively stable circulation zone around the robot body. This circulation zone can effectively weaken the backflow or eddies caused by the geometric changes of the steps in the water, thereby reducing the impact of the turbulence generated by the underwater levitation module on the robot's attitude. As a result, the underwater levitation module can maintain an approximately constant levitation thrust output at different water depths, making the pool robot's movement trajectory in the water, especially when switching between multi-level steps, smooth and less prone to deviation or tipping due to external water flow interference.

[0072] Furthermore, the structural relationship of maintaining the ratio between the diameter of the mounting hole and the rotor speed within the range of 0.0133 mm / (r / min) to 0.08 mm / (r / min) can also improve the energy utilization efficiency of the underwater suspension module during operation. Since the jet diffusion angle is controlled within a reasonable range, the kinetic energy reflected back to the surface of the machine body is reduced, avoiding random pressure peaks formed in the turbulent zone, thereby reducing the ineffective energy consumption of the motor and extending the service life of the module. For swimming pool environments with different water quality conditions, such as fresh water, salt water, or circulating water containing fine suspended particles, this ratio range can still maintain good stability and versatility.

[0073] When controlling the swimming pool robot to hover and land on the first step of the stepped area, precise control of the robot's attitude can be achieved by dynamically adjusting the levitation thrust output of the underwater levitation module. For example, in the first stage, the levitation thrust output of the underwater levitation module can be adjusted to gradually levitate the robot until the levitation height is greater than the height of the plane containing the first step, maintaining a static levitation state. In the second stage, by adjusting the roll angle of the swimming pool robot or the lateral drive module on the robot, the robot can be moved to directly above the first step. In the third stage, while hovering, the levitation thrust is gradually reduced, allowing the robot to approach and contact the step at a controllable speed, thus achieving a smooth landing. Simultaneously, during the levitation descent, the tilt angle, pitch angle, and roll angle of the robot can be continuously monitored, and the levitation thrust output of the underwater levitation module can be differentially adjusted based on this data. For example, assuming at least two underwater levitation modules, if the thrust output of the front underwater levitation module is slightly higher, the front of the swimming pool robot tends to tilt upwards. At this time, the rotation speed of the front underwater levitation module can be reduced, and the rotation speed of the rear underwater levitation module can be increased to make the robot return to a horizontal position.

[0074] By equipping the pool robot with an underwater levitation module that generates controllable thrust underwater, the pool robot can switch between steps without relying on the adsorption contact support of the step surface. It can also complete attitude adjustment and approach each step surface while in a levitation state. This allows the pool robot to have a relatively stable and controllable cleaning posture when it reaches the step surface to be cleaned, thereby improving the cleaning coverage of the step surface and avoiding the problems of missed cleaning of the step surface and insufficient cleaning of the step edges.

[0075] When the pool robot approaches the step surface while suspended, the controlled levitation thrust output cushions the robot's descent, allowing it to land more smoothly and gradually. This reduces the risk of momentary tilting or slippage caused by narrow steps or abrupt changes in support boundaries. This solves the problem of unstable landing posture, falls, and disruption of cleaning continuity caused by reliance on adhesive support in step areas. After landing, the underwater levitation module continues to provide adjustable vertical pressure, stabilizing the robot's position on the step and enhancing its adhesion and retention capabilities. This improves the stability of the robot's walking and cleaning movements on steps.

[0076] By maintaining the mounting hole diameter and the rotor speed of the underwater levitation module within a matching range of 0.0133 mm / (r / min) to 0.08 mm / (r / min), the water flow generated by the rotor in narrow areas such as between steps can form a relatively stable and gentle flow field distribution around the robot body. This reduces the turbulence generated during the operation of the underwater levitation module, enabling the pool robot to achieve stable levitation motion in the water. This further improves the robot's posture stability when cleaning across steps, thereby increasing the cleaning coverage of the step surface and enhancing the cleaning effect. Furthermore, by limiting the ratio of the mounting hole diameter to the rotor speed within the above range, the jet exhibits relatively uniform and low-impact flow field characteristics when contacting the step area. This effectively reduces disturbance to deposits on the step surface, preventing impurities from being washed into the cleaned area, thus maintaining the cleanliness of the cleaned area and improving the continuity and quality of the overall cleaning process.

[0077] The step cleaning method in step S110 will be described in detail below.

[0078] In one example embodiment of this disclosure, the swimming pool robot can be levitated onto the first step surface of a staircase via an underwater levitation module through the following steps, specifically including: The pool robot can be levitated by activating the underwater levitation module; the levitation thrust of the underwater levitation module can be controlled to make the levitated pool robot reach the target roll angle, and drive the pool robot at the target roll angle to move laterally toward the first step surface; when the proximity to the first step surface is detected, the pool robot is controlled to land on the first step surface.

[0079] The "suspended state" refers to the dynamic balance between the thrust generated by the underwater levitation module and the combined force of the robot's weight and buoyancy in the water, enabling the pool robot to maintain a preset depth or move vertically. This process can be achieved by controlling the rotor speed to adjust the output thrust, thus enabling precise buoyancy control of the robot in the water. The rotor speed can be calculated in real time and continuously corrected for rotor thrust errors based on proportional-integral-derivative (PID) or model-predictive control (MPC) strategies, combined with attitude and acceleration feedback signals from the inertial measurement unit (IMU). This allows the pool robot to achieve steady-state suspension, levitation ascent, or levitation descent in the water.

[0080] The target roll angle refers to the angle around which the pool robot rolls around its forward axis (e.g., the forward axis could be...). Figure 2 and Figure 7 The desired roll angle (the X-axis in the diagram) can be used to generate a horizontal component force while maintaining the suspension balance of the pool robot, giving the robot a tendency to move laterally in the horizontal direction. By decomposing the thrust vector of the underwater suspension module, the resultant force is kept balanced in the vertical direction, while forming a lateral thrust component in the horizontal direction, thus enabling the pool robot to move laterally. In specific implementation, when at least two underwater suspension modules are symmetrically arranged around the pool robot, a roll torque is generated by increasing the rotation speed of one underwater suspension module and decreasing the rotation speed of the other underwater suspension module, causing the pool robot to rotate around the forward axis (e.g., the forward axis can be...). Figure 2 and Figure 7 The X-axis in the middle generates the roll angle (e.g., ...). Figure 3 and Figure 4 After the swimming pool robot rotates around the X-axis, the roll angle formed with the Y-axis is α. In an optional embodiment, to avoid insufficient vertical thrust due to an excessively large target roll angle, an upper limit for the target roll angle can be set. For example, the upper limit of the target roll angle can be set in the range of 2° to 10°, and can be dynamically corrected according to the current load of the swimming pool robot, the viscosity of the water, and the rotor thrust curve. This embodiment does not impose any special limitations on this.

[0081] Lateral movement refers to the process of propelling the pool robot towards the first step surface while maintaining a suspended state at a target height, propelled by a horizontal thrust component generated by the target roll angle. The target height refers to the vertical position adjusted and maintained by the underwater levitation module before lateral movement, which is at least higher than the height reference of the plane containing the first step surface. Specifically, the target height can be determined based on the spatial location of the first step surface, the step height difference, and the structural dimensions of the pool robot. This ensures that while maintaining controllable suspension, the bottom or at least part of the robot's body is within a preset height range above the first step surface, avoiding contact interference with the step edge or leading edge during lateral movement. By maintaining the pool robot at the desired target height, the jet generated by the underwater levitation module is not blocked by the leading edge of the step during lateral movement, ensuring sufficient suspension stability and preventing the robot's body from touching the step at the target roll angle, thus improving the robot's attitude stability when approaching the first step surface.

[0082] The pool robot can calculate the lateral distance error between itself and the first step surface based on the position information collected by the sensing module, and convert this error into a target roll angle adjustment command. For example, the sensing module may include an ultrasonic ranging sensor, a Time-of-Flight (ToF) camera, or an underwater stereo vision system to measure the distance and normal angle between the pool robot and the first step surface in real time. In one embodiment, an S-shaped acceleration / deceleration curve control strategy can be used to dynamically adjust the target roll angle, allowing the pool robot to gradually approach the first step surface with low acceleration, preventing attitude disturbances caused by sudden changes in roll angle during the approach. To reduce attitude instability caused by water disturbance or the irregular shape of the step surface, the target roll angle can be reduced and the total thrust appropriately increased when approaching the first step surface, allowing the pool robot to maintain a stable attitude as it approaches the first step surface. (Reference) Figure 4 As shown, the pool robot 210 can be suspended in a floating state by activating the underwater levitation module 211, and the levitation thrust of the underwater levitation module 211 can be controlled to make the suspended pool robot 210 reach the target roll angle, and drive the pool robot 210 at the target roll angle to move laterally towards the first step surface; when the proximity to the first step surface is detected to be completed, the pool robot 210 is controlled to land on the first step surface.

[0083] Upon detecting that the approach to the first step surface is complete, the pool robot is controlled to land on the first step surface. For example, when the distance between the pool robot and the first step surface is less than a preset threshold and the rate of change approaches zero, and the angle between the pool robot's attitude angle and the normal to the first step surface is less than a set value, it can be considered that the approach to the first step surface is complete. At this time, the rotor speed of the underwater levitation module can be gradually reduced so that the levitation thrust is slightly lower than the net force of gravity of the pool robot, thereby allowing the pool robot to fall slowly at a lower speed. When the distance between the pool robot and the first step surface is less than the preset approach distance, the rotor speed can be briefly increased to create airflow buffer, allowing the pool robot to make contact with the first step surface in a gentle manner. To prevent attitude instability caused by the small step width or abrupt edge changes, the thrust feedback signal of each underwater levitation module can be monitored in real time, and fine adjustments can be made according to the attitude change rate to ensure that the pool robot completes the landing in a horizontal attitude. After being positioned, the underwater suspension module can continue to rotate at a low speed in the opposite direction, providing continuously adjustable vertical pressure. This allows the pool robot to form a stable adhesion on the first step surface, enhancing its adhesion and resistance to disturbances during the cleaning process and preventing slippage or tilting caused by water flow reflection or boundary disturbances after positioning.

[0084] By adjusting the levitation thrust of the underwater levitation module in a suspended state to form a target roll angle, the pool robot can approach the first step surface in a stable state during lateral movement, thereby reducing body attitude sway caused by water disturbance or irregular step boundary. After reaching the approach position, it performs the landing action, which is based on the adjusted posture, thereby improving the landing accuracy and avoiding the problems of approach deviation and inaccurate cleaning start position caused by traditional contact crawling methods.

[0085] In one example embodiment of this disclosure, the pool robot can be controlled to land on the first step surface through the following steps, which may specifically include: When the pool robot hovers and moves to the top of the first step surface at the target roll angle, the levitation thrust of the underwater levitation module can be adjusted to switch the pool robot from the target roll angle posture to a horizontal posture, and the horizontally oriented pool robot can be controlled to land on the first step surface; or, when the pool robot hovers and moves to the top of the first step surface at the target roll angle, after controlling one side of the pool robot at the target roll angle to land on the first step surface, the levitation thrust of the underwater levitation module can be adjusted to make the other side land on the first step surface.

[0086] The transition from a target roll angle to a horizontal attitude can be achieved through thrust distribution of the underwater levitation modules. For example, roll angle, pitch angle, and angular velocity data output by the inertial measurement unit can be collected in real time, and the current attitude can be compared with the desired horizontal angle. The attitude error is calculated using a proportional-integral-derivative (PID) control algorithm, and the rotational speed of the underwater levitation modules is adjusted based on the magnitude of the attitude error. For instance, using at least two underwater levitation modules, when the pool robot is detected to be at the target roll angle, the thrust of the tilted module can be gradually reduced while the thrust of the other module is increased, creating a torque to counteract the roll angle. This makes the resultant force gradually parallel to the direction of gravity. The thrust change curve throughout the transition process can be a continuous and smooth curve to avoid attitude oscillations caused by sudden changes in thrust.

[0087] Once the pool robot switches to a horizontal position, the total levitation thrust of the underwater levitation modules can be reduced to a level less than the robot's current weight, allowing it to slowly descend towards the first step surface. If multiple underwater levitation modules are present, their rotational speeds should be synchronized, ensuring uniform thrust distribution and maintaining a horizontal posture during descent. To prevent excessive descent speed from impacting the step surface, a small thrust can be briefly increased approximately 5 to 10 millimeters from the first step surface to create a water flow buffer, allowing the robot to make gentle contact with the step surface. During landing on the first step surface, water flow disturbances may cause localized upwelling due to reflections from the step surface. In this case, gyroscopes can be used to detect and quickly correct the robot's posture changes in real time, preventing posture deviations or body vibrations caused by reflected water flow.

[0088] In another implementation, when the pool robot hovers and moves to directly above the first step surface at a target roll angle, one side of the robot at the target roll angle can be controlled to land on the first step surface first. At this time, by maintaining the target roll angle, the lower side of the tilted side can first contact the first step surface to form initial support. After contact with the first step surface, the thrust feedback and attitude change rate on the contact side can be detected. By gradually reducing the suspension thrust on the other side, the other side can be lowered, thereby achieving a smooth fit of the entire pool robot against the first step surface. To prevent the first landing side from being lifted due to water rebound, the suspension thrust on the contact side can be briefly increased at the moment of contact detection to form stable support, and then the thrust can be released slowly. Contact confirmation can be achieved through thrust current feedback, acceleration change detection, or a micro-pressure sensor signal installed at the bottom; this embodiment does not impose any special limitations on this.

[0089] In this single-sided landing mode, the pool robot can achieve progressive contact in narrow step areas, effectively reducing the impact force of the posture. The underwater suspension module can form a differential control mode under the coordination of the control module, so that the rotor on the opposite side maintains a moderate thrust output to counteract the turbulence generated by the edge of the step. Then, the landing process can be judged to be completed based on the contact feedback, and after stable contact on both sides, it enters the reverse low thrust maintenance state, thereby maintaining constant vertical pressure, enhancing the adhesion between the pool robot and the first step surface, and preventing tilting or slippage caused by uneven support on the step surface.

[0090] refer to Figure 3 As shown, when the pool robot 210 hovers and moves to directly above the first step surface at a target roll angle, the levitation thrust of the underwater levitation module 211 can be adjusted to switch the pool robot 210 from the target roll angle attitude to a horizontal attitude, and control the horizontally positioned pool robot 210 to land on the first step surface; or, refer to Figure 4 As shown, when the pool robot 210 is hovering and moving directly above the first step surface at the target roll angle, after controlling one side of the pool robot 210 at the target roll angle to land on the first step surface, the levitation thrust of the underwater levitation module 211 can be adjusted so that the other side lands on the first step surface.

[0091] By utilizing levitation thrust directly above the first step surface to smoothly transition from the target roll angle to a horizontal posture, or by first contacting the step from the inside and then landing in stages from the other side, sufficient force support area can be obtained for landing methods under different step width conditions. This effectively reduces the risk of instantaneous tilting and slippage during landing on narrow steps or across steps, transforming the landing action into a process of gradually establishing stable support. This improves the controllability and reliability of step landing, enhances the accuracy of the pool robot's landing position on the step surface, and thus improves the cleaning coverage of the step surface, ensuring cleaning effectiveness.

[0092] In one example embodiment of this disclosure, the pool robot may include a lateral drive module, which is a power component used to provide horizontal thrust underwater. The direction of the lateral thrust generated by the lateral drive module is at a preset angle to the direction of the levitation thrust generated by the underwater levitation module. The main function of the lateral drive module is to assist the pool robot in achieving precise lateral translation in a suspended state, thereby improving its maneuverability in multi-step scenarios. For example, the lateral drive module can adopt a jet propeller or a small DC propeller structure, which drives the rotor to generate horizontal jet thrust through a motor. This thrust direction can form an angle greater than 0° and less than 90° with the vertical thrust direction of the underwater levitation module. In practical applications, the pool robot can calculate the current lateral offset and thrust demand in real time based on feedback data from attitude sensors and distance sensors, and output a pulse width modulation signal to the lateral drive module, so that the lateral thrust output and the vertical thrust of the underwater levitation module form a combined force control. To prevent attitude disturbances caused by the superposition of thrust in different directions, the pool robot can use a vector synthesis algorithm to dynamically allocate the output of each module, ensuring synchronous coordination between suspension balance and lateral movement.

[0093] The jet thrust direction of the lateral drive module is at a preset angle to the levitation thrust direction of the underwater suspension module. This jet thrust direction can be fixed during the structural design phase or adjusted by the control module during the operation of the pool robot; this embodiment does not impose any special limitations on this. For example, a structure with a fixed angle between the jet thrust direction of the lateral drive module and the levitation thrust direction of the underwater suspension module is suitable for symmetrically arranged dual lateral drive modules, where two lateral drive modules are installed on the left and right sides of the pool robot's body, with their jet thrust directions distributed laterally along the body. Alternatively, a structure with an adjustable angle between the jet thrust direction of the lateral drive module and the levitation thrust direction of the underwater suspension module can use a motor servo mechanism to adjust the jet thrust direction of the lateral drive module, allowing the jet angle to vary within the range of 0° to 30°, thereby providing the optimal lateral thrust direction under complex flow field conditions. The control module can automatically adjust the jet angle based on the current roll angle and step surface direction to achieve optimal energy utilization and trajectory control.

[0094] The following steps can be used to levitate the pool robot onto the first step of the stairs: The pool robot can be suspended in a floating state by activating the underwater levitation module; when the suspended pool robot reaches the target position, the lateral drive module is activated to move the pool robot closer to the first step surface; when the proximity to the first step surface is detected, the pool robot is controlled to land on the first step surface.

[0095] The target position refers to the docking position calculated based on the spatial coordinates of the first step surface measured by the sensing module and the normal direction of the step surface. The control module compares the current coordinates of the pool robot with the target position coordinates to calculate the lateral displacement error. The lateral drive module can output a corresponding horizontal thrust based on this lateral displacement error, enabling the pool robot to move horizontally towards the first step surface while maintaining a stable levitation state. To prevent attitude deviation during the approach, the control module can couple the thrust of the underwater levitation module with the thrust of the lateral drive module, adjusting the output ratio of each module in real time to ensure that the resultant force always points towards the predetermined center line of the motion trajectory. If water disturbance or local backflow is detected, the thrust of the lateral drive module can be automatically reduced and the vertical thrust can be compensated, thereby avoiding yaw during the approach path.

[0096] When the swimming pool robot is detected to have approached the first step surface, it can be controlled to land on the first step surface. For example, when the distance between the swimming pool robot and the first step surface is detected to be less than a preset distance threshold and the rate of change is close to zero, and the attitude sensor detects that the angle between the robot's tilt angle and the normal to the step surface is less than a preset angle threshold, it can be considered that the swimming pool robot has approached the first step surface. Subsequently, the levitation thrust of the underwater levitation module can be gradually reduced so that the levitation thrust is slightly lower than the net gravitational force of the swimming pool robot, thereby allowing the swimming pool robot to sink stably at a low speed.

[0097] In some alternative implementations, the lateral drive module can also employ a multi-jet array structure, where multiple small jets are distributed on both sides of the pool robot's body. Synchronous or differential control generates smooth lateral thrust to further reduce turbulence. Alternatively, the lateral drive module can use a bidirectional thrust reversing motor structure, achieving rapid switching of thrust direction through motor commutation for precise, short-distance translations within stepped areas. This can be combined with fuzzy control or sliding mode control to achieve stable approach under high dynamic response, maintaining trajectory convergence even in environments with complex water flow or irregular stepped surface morphology.

[0098] By positioning the thrust directions of the lateral drive module and the underwater suspension module at a preset angle, the pool robot can achieve lateral translation in a suspended state without relying on contact support from the pool bottom or step surface. This provides more flexible attitude adjustment capabilities in the narrow geometry of step areas. Furthermore, this suspension approach method with lateral compensation reduces the deviation caused by relying solely on longitudinal propulsion and suspension thrust, enabling the pool robot to maintain stable approach and accurate positioning at the edges of complex steps, thus improving the stability and reliability of the pool robot when moving between multiple steps.

[0099] In one example embodiment of this disclosure, the pool robot can be controlled to land on the first step surface in the following manner, specifically including: When the width of the first step surface is greater than or equal to the width of the pool robot's body, the pool robot can be driven to levitate directly above the first step surface through the underwater levitation module, and the entire projection area of ​​the pool robot on the first step surface is within the first step surface. At this time, the pool robot can be controlled to land on the first step surface.

[0100] The body width refers to the maximum structural dimension occupied by the pool robot in the lateral direction (i.e., the direction perpendicular to its working direction), used to measure the area occupied and support requirements of the pool robot on the step surface. The body width is determined by all lateral extensions of the pool robot, including the main shell, lateral structural components, protruding sensors, and decorative trim strips, and is a crucial geometric parameter for forming a stable stress zone on the first step surface. The body width can be measured using a circumscribed rectangle method, where the maximum distance between the outermost lateral structures of the pool robot is taken as the width reference. If there are asymmetrical devices on both sides of the body, such as lateral drive modules or shell anti-collision structures, the distance between the farthest points of the outer edges is used as the body width value.

[0101] When controlling the pool robot to land on the first step surface using the underwater levitation module, the relationship between the robot's body width and the width of the first step surface directly affects the landing strategy. For example, when the width of the first step surface is greater than or equal to the width of the robot body, the step surface can provide a complete support area for the pool robot. After landing, the pool robot can form a stable support torque distribution on the step surface, and all contact points are within the step surface range, without force bias or suspended areas. In this case, the landing method can adopt an overall vertical descent method, with the underwater levitation module providing uniform vertical thrust to ensure that the robot body maintains a horizontal attitude or the attitude of the target roll angle during landing. When the width of the first step surface is less than the width of the robot body, the step surface cannot provide full-width support for the pool robot, inevitably resulting in part of the robot body being suspended. In this case, the landing method can ensure the stability of the robot body after landing by using the attitude of the target roll angle and a phased contact method, such as establishing a support point on the inner side of the robot body first, and then allowing the suspended side to slowly transition into landing. During the suspension and positioning phase, the width of the aircraft can be projected onto the step surface. The projection coverage can be calculated in combination with the width of the step surface. The roll angle and thrust difference that need to be compensated can be evaluated based on the difference. This ensures that the landing process can establish stable support and prevent the aircraft from suddenly slipping due to its size exceeding the width of the step.

[0102] In one embodiment, when the width of the first step surface is greater than or equal to the width of the pool robot's body, it can be assumed that the pool robot's body is completely within the first step surface after landing, meaning the pool robot has complete force balance on the step surface and no part of its body is suspended in the air. During the process of suspending the pool robot directly above the first step surface using the underwater levitation module, the three-dimensional coordinates of the pool robot in the water can be determined based on its real-time attitude. The outline of the pool robot at its current suspended position is projected onto the step surface coordinate system, and it is determined whether the projected area completely falls within the boundary of the first step surface. When the entire projected area of ​​the pool robot on the first step surface is within the first step surface, or the distance between the edge of the projected area and the edge of the first step surface is greater than a safety threshold, it can be confirmed that the current landing position on the first step surface can fully support the pool robot. The process of controlling the pool robot's landing on the first step surface has been described in other embodiments and will not be repeated here.

[0103] refer to Figure 5 As shown, when the width of the first step surface 221 is greater than or equal to the width of the body of the pool robot 210, the pool robot 210 can be driven to levitate directly above the first step surface 221 through the underwater levitation module, and the entire projection area of ​​the pool robot 210 on the first step surface 221 is within the first step surface 221. At this time, it can be considered that the body of the pool robot 210 can be completely within the first step surface after landing, that is, the pool robot 210 has complete force balance on the step surface and there will be no part of the body suspended in the air. The pool robot 210 can be directly controlled to land on the first step surface 221.

[0104] By ensuring that the width of the first step surface is not less than the width of the robot body, the pool robot is suspended directly above the step surface and its projection area is completely within the step range. This allows the robot's landing action to be performed on the step surface with a complete support surface, avoiding body tilting caused by force bias during landing and making the landing process more stable. After landing, the pool robot obtains a uniform support torque on the step surface, making the subsequent cleaning trajectory execution more stable and continuous, reducing cleaning omissions caused by body shaking, and improving the cleaning coverage of the step surface.

[0105] In one optional embodiment, when the width of the first step surface is less than the width of the pool robot's body, the pool robot can be driven to levitate directly above the first step surface using an underwater levitation module, and the projection area of ​​the pool robot on the first step surface covers the entire width of the first step surface. In this case, the pool robot is controlled to land on the first step surface. When the width of the first step surface is less than the width of the pool robot's body, it can be assumed that after landing, part of the pool robot's body will not be fully supported by the first step surface. Therefore, based on the pre-measured boundary point set of the first step surface and the step surface normal, a local coordinate system for the step surface is established. The three-dimensional pose of the pool robot in the water is projected onto the step surface to obtain the projection area, and the lateral coverage between the projection area and the boundary of the first step surface is calculated in real time. If the lateral coverage satisfies the condition that the lateral span of the projection area is greater than or equal to the width of the first step surface, and the excess of the suspended edge is within a safe threshold, then the projection area of ​​the pool robot on the first step surface is marked as covering the entire width of the first step surface. It is understood that if the excess of the suspended edge exceeds the safe threshold, it can be considered that the first step surface cannot stably support the landing of the pool robot. In this case, the thrust of the underwater levitation modules can be controlled. If there are at least two underwater levitation modules, during landing, the underwater levitation module on the suspended side can continuously output levitation thrust, while the underwater levitation module on the other side can continuously output vertical pressure, ensuring that at least part of the pool robot's body is tightly attached to the first step surface. The control of the pool robot landing on the first step surface has been described in other embodiments and will not be repeated here.

[0106] refer to Figure 6 As shown, when the width of the first step surface 221 is less than the body width of the pool robot 210, the pool robot 210 can be driven to levitate directly above the first step surface 221 through the underwater levitation module, and the projection area of ​​the pool robot 210 on the first step surface 221 covers the entire width range of the first step surface 221. At this time, the body part of the pool robot 210 can be placed on the step as much as possible to obtain the support of the step, and then the pool robot 210 can be controlled to land on the first step surface 221.

[0107] By suspending and positioning the robot directly above the step even when the step width is smaller than the robot's body width, and ensuring that the projection area covers the entire step width, the robot's body lands on the step as much as possible. This allows the robot to achieve a controllable landing state even when partially suspended, thanks to its levitation thrust. This avoids situations where the robot cannot enter the cleaning area due to insufficient step area. This preset projection coverage landing mode enables the robot to land even in narrow step areas, enhancing its cleaning capabilities in complex step scenarios and improving its cleaning coverage and effectiveness in multi-level complex step scenarios.

[0108] In an optional embodiment of this disclosure, when the width of the first step surface is less than the body width of the pool robot, the pool robot can be controlled to land on the first step surface through the following steps, which may specifically include: The levitation thrust of the underwater suspension module can be adjusted so that the pool robot approaches the first step surface at the target roll angle. At this time, the side of the pool robot that is closer to the inside of the first step surface lands on the first step surface first. The inside of the first step surface is the side away from the side of the pool robot that is suspended on the first step surface.

[0109] The target roll angle is the roll angle adopted by the pool robot when it is horizontally displaced to directly above the first step surface. At this target roll angle, as the pool robot descends towards the first step surface, the inner side of the robot is slightly lower vertically than the suspended side. Based on the roll angle and angular velocity feedback from the inertial measurement unit, the attitude deviation can be converted into thrust adjustment commands for the underwater levitation modules. The thrust of the inner underwater levitation module is proportionally reduced, decreasing the vertical reaction force on the pool robot as it approaches the first step surface, while the thrust of the suspended underwater levitation module is moderately increased to provide some supporting torque, thus creating an overall inward tilting posture.

[0110] When the pool robot approaches the first step surface with the target roll angle, the inner side of the robot lands on the first step surface first. The inner side refers to the part of the robot that is closer to the adjacent step side of the first step surface than the suspended side under the action of the target roll angle. Since the roll angle has already placed the inner side of the robot in a relatively low position during the approach phase, the total thrust can be gradually reduced to contact the first step surface at a lower speed when approaching it. The contact point can be confirmed by criteria such as the micro-impact peak of the accelerometer, the pressure change of the micro-pressure sensor, or the reverse feedback of the current of the underwater levitation module. After contact occurs, the thrust of the underwater levitation module on the suspended side can be maintained to keep the suspended side in a suspended state, avoiding lateral recoil caused by simultaneous landing on both sides. By landing on one side first, the pool robot can establish a first contact support point on narrow step surfaces with low impact, giving the landing process geometric constraints and preventing the robot from becoming unstable on both sides due to overall sinking.

[0111] After the inner side of the robot lands on the first step, the other side lands on the same step. During this phase, the thrust of the underwater levitation module on the suspended side is gradually released, allowing the suspended side to descend slowly. Specifically, based on the attitude change after contact with the inner side, the target roll angle is controlled along a gradually returning trajectory, while the thrust of the underwater levitation module on the suspended side is gradually reduced according to the step contact rhythm, allowing the suspended side to approach the step surface at a slow speed. After contact, the underwater levitation module on the inner side continues to rotate in the opposite direction at a low speed, providing a certain vertical pressure to the pool robot, stabilizing the robot's center of gravity on the first step. Ultimately, through this phased landing method—the inner side landing first, followed by the suspended side—the pool robot achieves stable contact on the first step, which is not wide enough to fully support the robot, significantly reducing the overall impact and lateral slippage probability, and improving the robot's attitude stability during cleaning operations on stepped areas.

[0112] By adjusting the suspension thrust, the pool robot approaches the inside of the step at the target roll angle, prioritizing the establishment of an inner support point during landing. Then, it gradually lands on the suspended side using a slow descent method, significantly reducing the risk of tipping over and slipping on narrow steps due to a single landing. This phased landing mechanism enables the pool robot to form a stable support combination on steps with insufficient width, ensuring the continuity and stability of the cleaning action.

[0113] In one example embodiment of this disclosure, before the pool robot is levitated and lands on the first step surface of the steps by the underwater levitation module, the position information of the steps and the global cleaning path of the steps can be obtained; based on the global cleaning path, the pool robot is driven to the starting point of the steps, which is located at one end of the step area near the uppermost or lowermost step.

[0114] The positional information of the steps refers to the result of scanning and 3D reconstruction of the geometric position, orientation, and hierarchical structure of the steps in the three-dimensional space of the pool by the perception module before the pool robot enters the step area. The positional information of the steps can include the normal direction of each step surface, the set of boundary points on the step surface, the height difference of the step surface, and the relative orientation relationship between each level of steps. For example, the perception module can use ultrasonic ranging arrays, time-of-flight cameras, underwater vision sensors, or structured light sensors, and combine them with attitude angle information provided by the inertial measurement unit. A multi-source fusion algorithm is used to spatially register the original measurement data, so that the position of the step area in the pool coordinate system is accurately expressed. Once the positional information of the steps is established, it can be stored locally or in the cloud as a 3D point cloud or a parametric planar model for subsequent path planning and hovering positioning. In some optional implementations, deep learning feature extraction methods can be used to perform semantic segmentation of the underwater visual images, automatically identifying the steps' edges and surfaces, improving the recognition ability for low-texture or unevenly lit scenes; this embodiment is not limited to this.

[0115] A global cleaning path refers to the cleaning access sequence and route planning covering the entire step area, typically generated based on the global geometric relationship containing multiple steps. During global cleaning path planning, the hierarchical structure and geometric model of the steps can be used as input to generate a global path starting from the beginning of the step area, based on the pool robot's accessibility constraints, mobility capabilities, and cleaning coverage requirements. The path planning process can be based on grid methods, search algorithms (such as the A* algorithm), or continuous space-based sampling algorithms such as Rapidly-exploring Random Tree (RRT). In this planning, each step surface is typically treated as a node, and the movement paths between nodes are connected by the pool robot's underwater hovering, upward, and downward movements, forming a cross-level 3D path graph. In some alternative implementations, to improve robustness to water disturbances, the edge areas of the step surfaces can be designated as high-cost areas, causing the cleaning path to preferentially unfold in the central area of ​​the step surface, avoiding robot instability caused by proximity to the boundaries. The global cleaning path can be a multi-segment structure, with each segment representing the specific movement direction and cleaning sequence of the pool robot after reaching a certain step surface. For example, it could clean step by step from the top down or step by step from the bottom up. Optionally, deep learning strategies can be incorporated into the path planning to learn the optimal route from historical cleaning data, making the path more consistent with actual cleaning efficiency.

[0116] The starting point of a step refers to the first step surface or its corresponding spatial coordinates defined in the global path for entering the step area. The starting point is located near either the top or bottom step, depending on the global cleaning path planning strategy. Based on the current position and attitude of the pool robot, the shortest feasible path to the starting point of the step can be calculated, and the robot can move to the starting point of the step area by driving the propulsion module or using the underwater levitation module. When moving using only the propulsion module, the pool robot can travel along the bottom or wall of the pool to the planned starting position. When it needs to overcome obstacles or perform non-contact movement, the underwater levitation module can be driven into a levitation state, and a small range of three-dimensional spatial drift can be achieved by fine-tuning the levitation thrust, allowing the pool robot to reach the starting point of the step area non-contactly. After reaching the starting point of the step area, the current position can be set as the starting coordinates for the cleaning action, so that subsequent levitation positioning, attitude adjustment, and landing operations can be carried out at the accurate starting position.

[0117] By acquiring step location information and global cleaning paths in advance, the pool robot establishes an environmental awareness of the step hierarchy and entry direction before entering the step area. This avoids path deviations caused by blindly approaching the step area. This guided entry based on global paths enables the hovering and landing actions to be performed at the correct step entrance, improving the planning completeness and path consistency of cross-step cleaning tasks, making the coverage of the step area more comprehensive, thereby improving the cleaning coverage of the pool robot on the step area and enhancing the cleaning effect of the step area.

[0118] In one example embodiment of this disclosure, when the starting point is located near the end of the uppermost step, the step surface of the uppermost step is the first step surface. The underwater levitation module causes the pool robot to levitate downwards and land at the starting position of the first step surface of the step. When the starting point is located near the end of the lowermost step, the step surface of the lowermost step is the first step surface. The underwater levitation module causes the pool robot to levitate upwards and land at the starting position of the first step surface of the step. The levitation thrust of the underwater levitation module is less when the pool robot levitates downwards than when it levitates upwards.

[0119] The uppermost step is the highest level in the step area in the vertical direction, and its surface is usually closest to the area above the pool water. Downward levitation refers to the pool robot reducing the thrust of its underwater levitation module so that the net force is slightly less than the sum of gravity and buoyancy, thus creating a controlled, slow descent. The pool robot's control module can calculate the current levitation height and descent speed in real time based on feedback data from the inertial measurement unit and depth sensors. It then adjusts the rotor speed of the underwater levitation module using proportional-integral-derivative control or model predictive control to keep the descent rate within a defined range (e.g., less than 0.02 m / s). The initial position can be determined by measuring the distance to the step surface using distance sensors (such as ultrasonic ranging or time-of-flight cameras), and the attitude angle data provided by attitude sensors ensures that the landing position is geometrically aligned with the first step surface.

[0120] The lowest step refers to the bottom step in the stepped area, whose height is closest to the bottom of the pool. Upward levitation refers to increasing the rotor speed of the underwater levitation module so that its total thrust output is slightly greater than the resultant force of gravity and buoyancy, thus generating a controllable upward trend. The thrust required for upward levitation is higher because the underwater levitation module needs to overcome gravity and water resistance; therefore, the thrust setting is usually higher than for downward levitation, for example, about 10% to 30% higher, to maintain sufficient climbing margin. The pool robot can adjust the thrust of the underwater levitation module through closed-loop control based on real-time attitude data from the inertial measurement unit and depth data from the depth sensor, allowing the pool robot to levitate and rise vertically, moving towards the top of the lowest step.

[0121] refer to Figure 7 As shown, when the starting point A is located near the top step, the surface of the top step is the first step surface 221. The underwater levitation module 211 causes the pool robot 210 to levitate downwards along path AB and land at the starting position B of the first step surface 221. (Reference) Figure 2 As shown, when the starting point A is located at the end closest to the bottom step, the step surface of the bottom step is the first step surface 221. The underwater levitation module 211 enables the pool robot 210 to levitate upward along the path AB and land at the starting position B of the first step surface 221 of the step.

[0122] By selecting between downward or upward levitation based on the level of the step, the pool robot can step onto the target step surface in the correct direction. Different thrust levels are used to differentiate the power requirements between the upper and lower steps, allowing the pool robot to maintain stable momentum during step-crossing displacement. This reduces abrupt attitude changes caused by different directions of the steps. This directional adaptive levitation landing method improves the spatial accuracy of the pool robot entering the step area, making the landing starting point more consistent with the cleaning trajectory plan and improving the cleaning efficiency of the step area.

[0123] In one example embodiment of this disclosure, the step contour information of the first step surface can be obtained; a local cleaning path of the pool robot on the first step surface can be planned according to the step contour information; wherein, the local cleaning path includes the starting position and the ending position of the cleaning travel path of the pool robot on the first step surface, with the position where the pool robot suspends and first lands on the first step surface as the starting position.

[0124] The step contour information refers to the set of data that characterizes the shape boundary and geometric distribution of the first step surface in the local coordinate system. For example, the step contour information can include the planar range of the first step surface, the position of the edge line, the shape of the outer contour, the position of the corner points, and possible concave and convex variations. The pool robot can obtain the step contour information from local storage or cloud storage, or it can project the multi-frame distance data and image data collected by the perception module onto the height plane where the first step surface is located, and extract the outer contour line and inner contour line of the first step surface from the continuous point set through edge detection, clustering, or fitting algorithms, forming the step boundary represented by multiple polylines or parametric curves. For relatively regular rectangular or near-rectangular steps, the step contour can be characterized by the minimum bounding rectangle or polygon fitting method; for steps with rounded corners, beveled edges, or irregular concavities, fine characterization can be achieved by increasing the sampling density and the number of boundary points. When extracting the contour information, the height difference between the first step surface and the next step or the bottom of the pool can be recorded simultaneously to mark the dangerous boundary area near the outer side of the step, which can be used to set up a safety buffer zone when planning the local cleaning path later. The step contour information obtained in this way can not only reflect the horizontal range of the first step surface, but also be used to identify the geometric feature areas of the step surface, so that the subsequent cleaning path can automatically shrink or slow down when it is close to the edge, reducing the risk of falling.

[0125] Local cleaning paths can be used to define the cleaning coverage area and cleaning sequence of a pool robot on a first step surface. For example, a feasible cleaning area can first be generated within the step surface described by the step contour information. Then, based on the width of the pool robot body and the effective cleaning width of the cleaning components, the feasible cleaning area of ​​the first step surface can be divided into several parallel cleaning strips. The spacing between the strips can be slightly smaller than the effective width of the cleaning components to create a certain overlap and reduce cleaning dead zones. The intersection points of each strip with the step boundary are determined based on the step contour information, and by optimizing the strip sequence, a roughly round-trip or serpentine local cleaning path covering the first step surface is generated. In an optional implementation, the turning radius, maximum allowable roll angle, and speed limit constraints in the step edge area of ​​the pool robot can also be considered when planning the local cleaning path. This ensures that the planned local cleaning path reduces sharp turns and frequent attitude adjustments while maintaining complete coverage, thus improving the smoothness of the cleaning process.

[0126] In a local cleaning path, the starting position of the cleaning path can be determined by combining the coordinates of the pool robot's initial hovering and landing on the first step. When the starting position of the local cleaning path is the position where the pool robot hovers and first lands on the first step, this starting position can be projected onto the pre-divided set of cleaning strips. The cleaning strip closest to or containing the starting position is selected as the first cleaning path strip, and the corresponding starting point on this strip is set as the starting point of the cleaning path. In this way, after completing its hovering and landing, the pool robot can directly begin cleaning along the starting direction of the local cleaning path without additional starting position adjustments or complex repositioning operations. The ending position can be determined based on the coverage order of the local cleaning path as the end point of the last cleaning strip, or it can be set at a position that facilitates the continuation of the next step or the next cleaning area, depending on the needs of the global cleaning path; this embodiment is not limited to this.

[0127] By acquiring the contour information of the first step surface and generating a local cleaning path that matches the geometric features, the cleaning trajectory can conform to the actual shape of the step, thus avoiding insufficient edge cleaning and corner cleaning omissions caused by fixed path patterns. By using the initial floating landing point as the cleaning start point, the cleaning action starts from the precisely positioned landing position, achieving path continuity and improving the depth cleaning capability of the step. Furthermore, by establishing a binding relationship between the floating landing position and the starting position of the local cleaning path, a natural connection from the floating landing to the cleaning movement is achieved on the first step surface, avoiding unnecessary posture adjustments and displacement movements introduced due to the inconsistency between the starting position and the landing position. This reduces the posture instability and fall risk caused by repeated starts, stops, and turns in the narrow area of ​​the step, making the local cleaning process of the first step surface more continuous and controllable, and improving the cleaning coverage of the step surface.

[0128] In one example embodiment of this disclosure, when the cleaning of the first step surface is completed, if an uncleaned second step surface is detected, the end point of the cleaning process on the first step surface is taken as the new starting point. The new starting point is the starting point of cleaning the uncleaned area on the step, and the pool robot is suspended and landed at the starting point of the second step surface by the underwater suspension module.

[0129] The detection criteria for completing the cleaning of the first step surface can include a cleaning path completion signal, cleaning coverage records fed back by the sensing module, and closed-loop confirmation of the robot's trajectory. The cleaning path completion signal can be automatically triggered by the control module after all strips of the local cleaning path have been completed, and the cleaning coverage records can be verified by a vision sensor. Once it is confirmed that the first step surface has been cleaned, the pool robot can read the end point of the final strip of the cleaning path as the endpoint position and project this endpoint position onto the pool coordinate system as the new starting point for the next stage of action. That is, the new starting point is the starting position for cleaning the uncleaned areas on the step area.

[0130] When a second step surface is detected as uncleaned, its vertical relationship relative to the first step surface can be determined based on the step hierarchy information in the global cleaning path. The endpoint of the first step surface can then be used as the new starting point, ensuring continuity and spatial coherence in the cleaning process. The starting position of the second step surface can be calculated based on the step geometry model. This starting position can be a point on the second step surface that is spatially connected to the current starting point of the first step surface, such as an edge near the upward direction of the step or the optimal access point determined by path planning. In an optional implementation, to ensure the rationality of the cross-step movement path, a three-dimensional path planning algorithm can be used. Factors such as fuselage size, height difference between steps, step width, and fuselage width can be incorporated into the planning constraints, ensuring that the transition path from the endpoint of the first step surface to the starting position of the second step surface satisfies safety distance, obstacle avoidance constraints, and attitude control constraints.

[0131] After setting the endpoint as the new starting point, the underwater levitation module allows the pool robot to detach from the support of the first step and enter a levitation state. During this stage, the underwater levitation module increases thrust to a level slightly greater than the sum of gravity and buoyancy, causing the pool robot to drift slightly upwards, avoiding mechanical obstruction caused by protrusions, depressions, or undulations at the step edge. Subsequently, based on the position data of the second step, the pool robot can calculate the spatial displacement vector and target landing posture, and use the underwater levitation module and / or lateral drive module to control the pool robot to levitate and approach the second step.

[0132] After the pool robot hovers and lands on the second step, its landing point can be used as the starting point for the local cleaning path on the second step. This allows the pool robot to plan and execute the local cleaning path on the second step using continuous path logic. The entire step-crossing process is completed in a suspended state, without relying on the physical climbing method at the edge of the step, enabling the pool robot to maintain the continuity of the cleaning process, posture stability, and path consistency in a multi-step structure.

[0133] By using the cleaning endpoint as the new starting point after the first step surface is cleaned, the cross-step cleaning process does not require repositioning, thus avoiding cleaning interruptions caused by repeatedly approaching or searching for the starting point again, improving cleaning continuity, and reducing cleaning blind spots; then the underwater suspension module performs cross-step suspension and landing, so that the transition from one step cleaning area to the next step cleaning area remains continuous, improving the coherence and cleaning coverage of the overall step sequence cleaning.

[0134] In one example embodiment of this disclosure, if the pool robot is detected to have fallen from the first step surface, the pool robot is driven back to the starting point corresponding to the first step surface. This starting point is the starting position for cleaning the uncleaned area on the step. The pool robot is then suspended by the underwater levitation module and lands at the starting position of the first step surface to continue performing the cleaning task of the first step surface.

[0135] The drop detection can be based on a comprehensive judgment of information from multiple sensors. For example, a drop event can be identified based on parameters such as sudden acceleration changes, rapid changes in angular velocity, and excessive attitude deviation rates monitored by the inertial measurement unit. Alternatively, it can be combined with pressure sensors to detect the sudden disappearance of the support force at the bottom of the fuselage, or with depth sensors to determine whether there is a rapid change in the height relationship with the step surface that does not conform to the normal cleaning path. This embodiment does not impose any special limitations on these methods. In one embodiment, the judgment of a drop event can also adopt a time window threshold method, which performs short-term fusion of multiple sensor signals. When multiple signals simultaneously meet the drop characteristic conditions, it is considered that a drop has occurred.

[0136] When driving the pool robot back to the starting point on the corresponding step, the return path can be calculated based on the spatial coordinate relationship between the fall location and the target step. The fall location is usually located in the water below or beside the step. The return path planning can determine a safe and feasible return trajectory based on the current depth, horizontal position, and step outline information. In one embodiment, a three-dimensional path planning algorithm can be used, such as grid search or continuous spatial interpolation, to construct a return path from the fall location to the target starting point. Obstacle areas (such as the lower edge of the step, vertical corners, etc.) are marked as non-crossable areas to ensure that the pool robot does not collide with the step structure during the return process. During the process of driving the pool robot back to the starting point, the underwater levitation module plays a crucial role in attitude adjustment and spatial movement.

[0137] After the pool robot returns to the starting point corresponding to the first step, it can be suspended at the starting position on the first step by the underwater levitation module, and then return to the place where it fell according to the local cleaning path to continue cleaning along the uncovered cleaning path, or clean again according to the local cleaning path.

[0138] By automatically returning to the starting point of the corresponding step and re-suspending after detecting a fall, the pool robot possesses fall recovery capability, thereby avoiding cleaning gaps and path interruptions caused by falls. This automatic return and re-suspension process allows the pool robot to quickly return to the cleaning task chain, ensuring the complete execution of the step cleaning task and improving the reliability and fault tolerance of operations in the step area. Furthermore, by returning to the starting point to continue the previous cleaning task, the risk of path errors or collisions that may occur when the pool robot replans its recovery path can be effectively avoided, improving the reliability and accuracy of cleaning task execution.

[0139] In one example embodiment of this disclosure, if a pool robot is detected to have fallen from the first step, the underwater levitation module enables the pool robot to levitate back to its original position before the fall based on its position information before the fall, and then continue to perform the cleaning task on the first step after returning to its original position.

[0140] The position information prior to the fall refers to the spatial information recorded by the encoder data of the attitude sensor, depth sensor, inertial measurement unit, or body travel drive module during the cleaning task on the first step surface. This information characterizes the swimming robot's trajectory, attitude angle, horizontal displacement, and height position on the first step surface. For example, the position information may include the current path segment number of the swimming robot on the cleaning path, the position offset within that path segment, horizontal attitude parameters, and the relative height distance between the robot and the step surface. By updating this information in real time, the control module can accurately identify the swimming robot's original cleaning position on the step surface when a fall event occurs.

[0141] After detecting that the pool robot has fallen from the first step, its position information before the fall can be read first, and the original position that the pool robot needs to return to can be determined based on the position information. Then, the underwater levitation module can be activated to generate controllable levitation thrust for the pool robot, allowing it to detach from the bottom of the pool or other supporting surface at the fall location, and gradually rise to a target height range above the first step while in a controllable levitation state.

[0142] After reaching a target height above the first step, the control module can use the position information before the fall as the target position on the first step. Then, by controlling the pool robot to move horizontally while remaining suspended, the pool robot returns to its original position before the fall. Of course, the specific return process can be described in other embodiments, and will not be elaborated here.

[0143] By directly returning to its original position before the fall based on the detected position information, the pool robot can resume its previous cleaning trajectory without altering its original cleaning path, thus avoiding missed cleaning sections or deviations in cleaning progress caused by the fall. The floating return method using the pre-fall position information allows the pool robot to quickly realign with its original cleaning path, ensuring continuous cleaning and improving the stability and consistency of the work process in the stepped area. By directly returning to its original position without needing to reposition itself at the step entrance, the recovery time after the fall is significantly reduced, allowing the pool robot to more quickly re-engage in the cleaning process of the area to be cleaned, thereby improving the overall efficiency of cleaning tasks in the stepped area.

[0144] In one optional embodiment of this disclosure, if a pool robot is detected to have fallen from the first step, an underwater levitation module suspends the robot at its original position before the fall, based on its previous location. If it successfully returns to its original position, the cleaning task on the first step continues. If it fails to return, the robot is driven back to the starting point corresponding to the first step, which is the starting position for cleaning the uncleaned area on the step. The underwater levitation module then suspends the robot at the starting position on the first step, allowing it to continue cleaning. The specific execution process will be described in other embodiments and will not be repeated here.

[0145] By prioritizing the attempt to return to the original position before the fall upon detecting a fall, the pool robot can quickly recover to the work point before the fall without altering the existing cleaning path. This reduces disruption to the cleaning rhythm caused by the fall and avoids cleaning gaps due to positional shifts. If the robot cannot successfully return to the original position, it switches to returning to the starting point corresponding to the first step, allowing it to re-establish contact with the step surface in a stable and controllable manner. This ensures that the cleaning task in the step area can continue smoothly after a fall. This dual-insurance fall recovery method gives the pool robot greater fault tolerance and adaptability in complex step environments. It can shorten the recovery time after a fall under suitable conditions and ensure the continuity and integrity of the cleaning process when recovery fails, thus improving the overall operational stability and cleaning efficiency in step areas.

[0146] This disclosure also provides a method for cleaning steps for a swimming pool robot. Figure 8 A schematic flowchart illustrating a step cleaning method for a pool robot according to other embodiments of the present disclosure is shown. Reference Figure 8 As shown, the step cleaning method for a pool robot may include the following steps: In step S810, during the process of the pool robot reaching the first step surface of the step and performing a cleaning task on the first step surface, if at least part of the pool robot is in a suspended state, the underwater levitation module is activated to keep the body posture of the pool robot stable.

[0147] The underwater levitation module refers to a power component that generates directional fluid thrust in water to achieve lifting, lowering, and attitude control of a pool robot. It can provide a reverse water flow acting in the direction of the pool robot's movement, thereby enabling the pool robot to levitate, float, or sink in the water. In an optional embodiment, the underwater levitation module can consist of an electric drive unit, a rotor assembly, and a jet guide structure. The electric drive unit can be a brushless direct current motor (BLDC) to achieve precise thrust adjustment through high-response speed control. The rotor assembly can be located at the motor output end to drive the water flow to form a directional jet. The jet guide structure can be a cylindrical, conical, or streamlined guide shroud to reduce flow resistance and improve the stability of the jet direction. The number of underwater levitation modules can be determined based on the relevant parameters of the pool robot. For example, there can be one underwater levitation module, located in the center of the pool robot; there can also be two underwater levitation modules, symmetrically distributed on both sides of the pool robot along the axis, or symmetrically distributed along the center of the pool robot; there can also be four underwater levitation modules, symmetrically distributed on the pool robot in pairs. This example embodiment does not impose any special limitations on the number of underwater levitation modules or their distribution on the pool robot.

[0148] The first step surface refers to the step-bearing surface in the step area where the pool robot is currently performing cleaning tasks. It can be a rectangular, arc-shaped, or polygonal combination structure, and its width, height, and height difference with adjacent steps are determined by the pool structure. When the pool robot travels along the cleaning path to the first step surface, it can form contact support with the first step surface through the travel drive module, and perform cleaning actions such as suction, brushing, and wiping on the step surface. The cleaning task can include traveling back and forth along a preset path to cover the entire first step surface, or it can include intensive cleaning in local areas, such as traveling back and forth multiple times to target areas with heavy dirt accumulation. Because there are step edges, upper and lower step facades, or local transition slopes around the first step surface, when the pool robot approaches these boundary areas along the cleaning path, some travel contact parts may no longer have solid structural support, resulting in at least part of the structure hanging outside the first step surface.

[0149] "At least partially suspended" means that a portion of the load-bearing structural area at the bottom of the pool robot is no longer in contact with the step surface, but is unsupported above the edge of the step or in an area with a height difference. Examples include one track or wheel losing contact, the front or rear end protruding beyond the step edge, or a corner of the robot crossing the step's vertical surface. This suspended state can be determined by various signals, such as detecting a sudden drop in contact pressure using a pressure sensor located near the driving module, detecting abnormal roll and pitch angle change rates using an inertial measurement unit (IMU), detecting a distance sensor indicating that the distance between one side of the robot and the step surface exceeds the normal range, or inferring a sudden change in support conditions through abnormal changes in the drive motor current. This embodiment does not specifically limit the method for detecting the suspended state. The control module continuously monitors these state variables during the cleaning task. When the preset suspended determination conditions are met, the pool robot is considered to have entered a state of at least partial suspension.

[0150] When the pool robot is detected to be at least partially suspended, the underwater levitation module can be activated to stabilize its attitude. The underwater levitation module generates a directional water flow in the water. This flow can be downwards, generating an upward levitation thrust to support the suspended side of the pool robot; or it can be upwards, creating a downward pressure force to provide vertical pressure, pressing the pool robot against the surface of the first step. The direction of the thrust can be designed and selected according to the specific structure and operating conditions; this embodiment does not impose any special limitations on this. When the underwater levitation module is activated, the control module can obtain the roll angle, pitch angle, and the relative position of the robot's center of gravity relative to the first step surface based on the current robot attitude information. Then, based on the direction of the suspended area and the proportion of the robot suspended, it determines the target thrust magnitude and operating time of the underwater levitation module. The thrust can be adjusted by changing the motor speed. The control method can be proportional-integral-derivative (PID) control or other closed-loop control algorithms. By comparing the deviation between the target attitude and the current attitude in real time, the hovering thrust is dynamically adjusted to make the fuselage attitude converge toward a stable state.

[0151] refer to Figure 9 As shown, at least part of the body of the pool robot 210 extends beyond the support range of the steps, so at least part of the body of the pool robot 210 is suspended in the air. At this time, the underwater levitation module 211 can be activated. The underwater levitation module 211 generates a downward directional water flow, which lifts the suspended body part through reaction force, so as to keep the body posture of the pool robot 210 stable.

[0152] In practical implementation, the underwater levitation module can employ a single levitation jet unit or multiple levitation jet units working in tandem. For example, a main levitation jet structure can be arranged in the central region of the module for overall support, while smaller levitation jet structures can be added at the edges for local attitude correction. To reduce the impact of jet disturbance on the surrounding water on the cleaning path, the nozzle shape of the underwater levitation module can be designed as a diffuser or porous type to create a softer and more uniform flow field. Alternatively, the jet outlet can be combined with a flow guide and a flow straightener to create a relatively stable reaction force distribution as the jet approaches the bottom of the module, avoiding excessive local impact.

[0153] By incorporating an underwater levitation module into the pool robot, when the robot is in a stepped area and some parts of its body cannot obtain support from the step surface, the underwater levitation module is activated to provide thrust. This allows the pool robot to maintain a stable body posture without relying on the complete support of the step surface. As a result, the cleaning components can form a more continuous and close contact with the step surface, which helps to improve the uniformity of cleaning coverage on the step surface, increase the cleaning coverage rate of the step surface, and avoid the problem of cleaning omissions on the step surface and its edge areas.

[0154] By providing appropriate levitation thrust during the step-crossing cleaning process, a buffer can be formed as the robot approaches the step surface, allowing the pool robot to gradually transition from a suspended state to stable contact. This reduces attitude deviation and slippage at the moment of landing, which helps maintain the continuity and stability of the step-crossing cleaning process.

[0155] After being positioned, the underwater suspension module can still maintain adjustable pressure in the step area, making the contact between the pool robot and the step surface more stable. This makes it less likely for the cleaning path of the pool robot to deviate in the step area, and also makes the cleaning coverage of the step edges and local narrow areas more sufficient. This allows the pool robot to achieve a more coherent cleaning process and higher cleaning reliability in multi-step scenarios, further improving the cleaning coverage of the step surface and the overall cleaning effect in multi-step scenarios.

[0156] In one example embodiment of this disclosure, if the width of the pool robot's body is greater than the width of the first step surface, and the overhang width of the body extending out of the first step surface is greater than or equal to a preset width threshold, then the underwater levitation module is activated to keep the body posture of the pool robot stable.

[0157] The body width refers to the maximum structural dimension occupied by the pool robot in the lateral direction (i.e., the direction perpendicular to its working direction), used to measure the area occupied and support requirements of the pool robot on the step surface. The body width is determined by all lateral extensions of the pool robot, including the main shell, lateral structural components, protruding sensors, and decorative trim strips, and is a crucial geometric parameter for forming a stable stress zone on the first step surface. The body width can be measured using a circumscribed rectangle method, where the maximum distance between the outermost lateral structures of the pool robot is taken as the width reference. If there are asymmetrical devices on both sides of the body, such as lateral drive modules or shell anti-collision structures, the distance between the farthest points of the outer edges is used as the body width value.

[0158] The first step width refers to the effective width of the step surface that can provide support in the lateral direction. Its size can be obtained by a pre-constructed step map, or by a pool robot scanning and measuring it using a lateral distance sensor, depth camera, or laser ranging component before entering the step area. This embodiment is not limited to this.

[0159] When the width of the pool robot's body is greater than the width of the first step surface, it can be assumed that the pool robot necessarily has a suspended area on the first step surface. In this case, the suspended width of the pool robot's body extending beyond the first step surface can be calculated. This suspended width can be obtained by projecting the contact contour of the robot's bottom onto the step surface coordinate system, or it can be obtained by measuring the distance difference between the robot's bottom and the step surface. For example, an infrared ranging array or ultrasonic ranging array can be used to obtain the distances between multiple bottom positions and the step surface, thereby identifying which areas are not in contact with the step surface. The calculation method for the suspended width can include the projection difference method based on a geometric projection model, or a pressure threshold method based on contact pressure distribution. This involves using a bottom pressure sensor group to determine which areas have lost support, and combining this with a preset contact surface mapping relationship to estimate the current suspended width. This embodiment does not impose any special limitations on this method. (Reference) Figure 9 As shown, the width of the pool robot 210 is obviously greater than the width of the first step surface 221, and the left side of the robot body exceeds the support range of the first step surface 221. At this time, it can be assumed that when the pool robot is moving on the first step surface, there is a suspended area on its left side.

[0160] A preset width threshold is used to determine whether the degree of suspension has reached a level that may affect posture stability. The preset width threshold can be pre-set based on the pool robot's center of gravity position, chassis structure, propulsion module layout, and body shape, and can be calibrated using experimental data. For example, when the suspension width exceeds a certain proportion, the outward shift of the robot's center of gravity will cause a significant roll angle deviation; therefore, the body width corresponding to this proportion can be set as the preset width threshold. In an optional embodiment, the preset width threshold can be 10%-30% of the width of the first step surface, or it can be dynamically adjusted according to the robot's size, center of gravity height, or suspension thrust capability. In another optional approach, the preset width threshold can also be adaptively updated in conjunction with the pool robot's travel speed and the current pitch and roll angle trends, ensuring the threshold remains within a reasonable range under different operating environments. This embodiment does not specifically limit the method for determining the preset width threshold.

[0161] When the detected overhang width is greater than or equal to a preset width threshold, it can be considered that the current overhang state may cause the robot's center of gravity to shift beyond the safe range, thus activating the underwater levitation module. When activating the underwater levitation module, the module required for compensation can be identified based on the orientation of the currently overhanging area. For example, if the overhanging area is on the right side of the pool robot, the underwater levitation module near the right side can be activated, spraying water downwards to create a reaction force. Alternatively, the underwater levitation module near the left side can be activated, spraying water upwards to create vertical pressure on the pool robot, providing compensatory support to the overhanging area. During actual propulsion, the jets generated by the underwater levitation modules create an upward reaction force below the overhanging side of the robot, counteracting the direction of the force shift and helping to suppress further increases in the roll angle. When the jets are upward, a downward pressure force is generated, which can enhance the adhesion of the non-overhanging side to the first step surface, improving the robot's traction on the non-overhanging side, thus achieving an effect similar to articulated support and making the overall posture more stable.

[0162] By activating the underwater levitation module, the robot's posture is kept within a controllable range, allowing the pool robot to continue cleaning on the first step without suddenly tilting, slipping, or even falling onto the next step due to excessive suspension. By using a comparison between the suspension width and a preset width threshold to trigger posture control, the pool robot has the ability to adapt to different step widths, enabling timely responses to sudden suspension situations. This improves the continuity and safety of the cleaning process in the step area, thereby enhancing the completeness and effectiveness of cleaning coverage on the first step.

[0163] In one example embodiment of this disclosure, when the body posture of the pool robot tilts unexpectedly, the underwater levitation module is activated to keep the body posture of the pool robot stable.

[0164] Unexpected tilting of the robot's body refers to a situation where, during the process of the pool robot moving or cleaning on the first step, its roll or pitch angle deviates from the range of its normal operating posture, causing the robot's center of gravity to shift away from the step's support area, resulting in a tilting trend that may affect the continuity of cleaning. The causes of unexpected tilting may include insufficient width of the first step leading to incomplete support points, or slight tilting due to localized water flow disturbances, debris accumulation, or some cleaning components of the pool robot entering gaps in the step. The pool robot can monitor its posture in three-dimensional space through its built-in inertial measurement unit, detect changes in angular velocity using a gyroscope, detect the direction of the gravity vector using an accelerometer, and identify the posture reference direction using a magnetometer. A comprehensive filtering algorithm is then used to determine the current tilt angle and direction of the body. Of course, other methods can also be used to detect unexpected tilting of the pool robot; this embodiment does not specifically limit this method.

[0165] When detecting unexpected tilt, the system continuously reads data output from the inertial measurement unit and compares the current body attitude with a preset normal attitude range. The normal attitude range can be set based on the structure of the first step surface and the working mode of the pool robot during step cleaning. For example, in horizontal working mode, the roll angle is required to be within ±5 degrees, while during cleaning on tilted steps, this range can be appropriately widened to ±10 degrees. This embodiment is not limited to this. When the roll angle or pitch angle exceeds the preset tilt angle range, the control module can determine that the body has tilted unexpectedly and calculate the underwater levitation module to be activated and its thrust direction based on the tilt direction. (Reference) Figure 10 As shown, the pool robot 210 can compare its current body posture with the preset normal posture range. When the roll angle of the pool robot 210 exceeds the preset tilt angle range, it can be determined that the body of the pool robot 210 has tilted unexpectedly, and the unexpected tilt is tilting to the left. At this time, the underwater levitation module 211 near the left side can be activated to stabilize the body posture of the pool robot.

[0166] When activating the underwater levitation module, the direction of the robot's tilt can be identified. When the robot tilts to one side, it indicates insufficient support on that side or that the center of gravity is biased towards that side. The control module then activates the underwater levitation module closest to the tilt direction. For example, when the pool robot tilts to the right, the right underwater levitation module is activated, spraying water upwards to generate a reaction force, providing upward support compensation to the right side of the robot and counteracting the tilting trend. If the tilt direction is to the left, the left underwater levitation module is activated, so that the spray direction is opposite to the direction of the center of gravity shift. In another optional approach, multiple underwater levitation modules can be activated simultaneously. For example, when the pool robot tilts to the right, the right underwater levitation module is activated to spray water downwards to create support, while the left underwater levitation module is activated to spray water upwards to create vertical pressure, forming a gentler, more evenly distributed compensation torque and reducing oscillations during attitude correction.

[0167] By activating the underwater levitation module when the robot body tilts unexpectedly, the robot body can obtain immediate attitude compensation, thereby preventing the tilt angle from increasing further. This prevents the pool robot from slipping, rolling, or falling onto the next step due to insufficient support. By actively adjusting the robot body attitude using the reaction force of water flow, the pool robot maintains a stable attitude during the step cleaning process, allowing the cleaning components to continuously adhere to the first step surface, improving the continuity and uniformity of cleaning coverage. In addition, through active attitude control capabilities, the pool robot can adapt to step areas with different structures, improving its applicability and cleaning reliability in complex pool structures.

[0168] In one example embodiment of this disclosure, the pool robot may include a propulsion module, which can activate the underwater levitation module through the following steps, specifically including: If at least part of the pool robot is suspended in the air, the levitation thrust of the activated underwater levitation module is adjusted to maintain the stability of the pool robot's posture during the cleaning process on the first step surface; and the driving force provided by the travel drive module enables the pool robot to continue cleaning along the cleaning path on the first step surface.

[0169] When at least part of the pool robot's body is suspended in the air, the levitation thrust of the activated underwater levitation module can be adjusted to maintain the robot's posture stability during the cleaning process on the first step. The principle of adjusting the levitation thrust is to compensate for the step support gap caused by the suspension of the body through the reaction force of the jet generated by the underwater levitation module, allowing the body to regain torque balance. The magnitude of the levitation thrust can be determined by the rotational speed of the motor inside the underwater levitation module. The higher the motor speed, the greater the dynamic pressure of the jet water, and the stronger the levitation thrust generated. In actual implementation, the jet intensity can be adjusted in real time according to the degree of suspension of the suspended side of the pool robot, the tilt angle of the body, and the tilt direction. For example, a linear adjustment method can be used to achieve continuously controllable thrust output, or a graded thrust mode can be used to allow the motor to switch between multiple fixed gears to achieve rapid response. This embodiment does not impose any special limitations on this.

[0170] In one embodiment, the thrust of the underwater levitation module can be directed downwards according to a fixed mounting structure, using the reaction force to lift the robot body and thus counteract the gravitational torque imbalance caused by suspension. In another optional embodiment, the underwater levitation module can employ a jet structure with an adjustable deflection angle, allowing the nozzle direction to vary within a certain angle range to adapt to attitude deviation compensation requirements in different directions, thereby maintaining a more stable attitude when the robot body travels along the edge of the step. By combining levitation thrust with body attitude control, the pool robot can maintain a stable cleaning contact state on the first step surface, avoiding problems such as body tilting, slippage, or cleaning components detaching from the step surface due to suspension. The instantaneous compensation provided by the water flow reaction force makes attitude adjustment more continuous, resulting in a smoother walking path for the robot on the step surface and improving the continuity of the entire cleaning process.

[0171] After the underwater levitation module stabilizes the swimming pool robot's posture, the driving force provided by the propulsion module allows the robot to continue cleaning along the cleaning path on the first step surface. The propulsion module can employ an underwater propeller, generating water flow thrust through a propeller to move the robot forward; or it can use underwater tracks, with left and right tracks moving synchronously on the step surface to generate linear thrust. By adjusting the driving power and output direction of the propulsion module through the control module, the swimming pool robot can move along the predetermined cleaning path on the first step surface while maintaining its posture balance under the underwater levitation module, and simultaneously maintain continuous contact with the surface of the first step.

[0172] Understandably, during the cleaning path advancement, the underwater levitation module's levitation thrust counteracts any instability caused by insufficient local support, while the propulsion module provides the driving force to ensure the pool robot can continue moving forward and achieve effective cleaning coverage. When the pool robot encounters uneven areas or slight height changes on the first step surface, the underwater levitation module can further adjust its posture through minute thrust changes, allowing the cleaning components to adhere closely to the step surface and avoid cleaning gaps.

[0173] By enabling the underwater suspension module and the propulsion module to work together, the pool robot can improve its posture stability during the cleaning of the first step surface, ensuring that the travel path is continuously controllable, so that the cleaning task can be completed smoothly. This avoids problems such as cleaning interruption or posture instability caused by partial suspension, improves the reliability and consistency of the entire step cleaning task, and enhances the complete coverage and cleaning effect of the step surface.

[0174] In an optional embodiment of this disclosure, the levitation thrust of the activated underwater levitation module can be adjusted through the following steps, specifically including: The levitation thrust of the underwater suspension module can be adjusted based on the width difference between the width of the pool robot's body and the width of the first step surface at the current position of the pool robot; the larger the width difference, the greater the levitation thrust.

[0175] The width difference is used to quantify the degree of mismatch between the current step support and the size of the pool robot, representing the extent to which the pool robot extends beyond the edge of the step at its current position. The portion of the pool robot's body width that extends beyond the width of the first step surface reflects the overhanging area of ​​the pool robot's chassis profile beyond the step support surface. This overhanging portion can be obtained by projecting the bottom surface of the pool robot in its current posture onto the step surface coordinate system and calculating the overlapping area and the exceeding area between the projected profile and the boundary of the first step surface. The difference between the body width and the width of the first step surface at the current position can be determined at each position update of the pool robot, with the portion extending beyond the edge of the first step surface used as the width difference.

[0176] The levitation thrust of the underwater levitation module can be adjusted in real time according to the principle that the greater the width difference, the greater the levitation thrust, so that the levitation thrust matches the current degree of suspension. When the width difference is small, for example, when the body of the pool robot only slightly exceeds the edge of the first step, the impact of the suspended body part on the overall center of gravity and supporting torque of the pool robot is small. In this case, only the motor speed of the underwater levitation module can be slightly increased to provide small support compensation for the levitation thrust, so as to avoid unnecessary energy consumption and flow field disturbance. When the width difference is large, it can be considered that more of the body part of the pool robot loses the support of the step, and the center of gravity is more biased towards the suspended side. In this case, the motor speed of the underwater levitation module can be increased to generate a larger reaction force from the jet, forming a stronger lifting effect on the suspended side, thereby compensating for the torque imbalance caused by the lack of support. The correspondence between the width difference and the suspension thrust can be achieved by linear mapping, that is, within the preset width difference range, the width difference is mapped proportionally to the target value of the suspension thrust. Alternatively, it can be achieved by piecewise linear mapping or table lookup, for example, by configuring different thrust levels for different width difference ranges, making the suspension thrust control simpler and more reliable.

[0177] By adjusting the levitation thrust of the underwater levitation module using the width difference as a control variable, the attitude control of the pool robot no longer relies solely on a single tilt angle. Instead, it directly reflects the extent to which the pool robot exceeds the geometrically supported area of ​​the first step surface. This allows for an early increase in levitation thrust when the geometric tendency to become suspended is still in its early stages, mitigating the risks associated with the outward shift of the center of gravity. As the suspended area expands, the levitation thrust automatically increases, providing stronger torque compensation to the suspended side and preventing the robot from suddenly tipping over or falling due to exceeding its support limits. This thrust adjustment mechanism based on the width difference enables the underwater levitation module to adaptively output different levels of support capacity as the step width changes, allowing the pool robot to maintain high attitude stability and cleanliness continuity under various step width conditions.

[0178] In an optional embodiment of this disclosure, the levitation thrust of the activated underwater levitation module can be adjusted through the following steps, specifically including: The levitation thrust of the underwater suspension module can be adjusted according to the tilt angle of the pool robot when it is at least partially suspended in the air; the larger the tilt angle, the greater the levitation thrust.

[0179] The tilt angle, or tilt angle, describes the degree to which the pool robot's posture deviates from its horizontal orientation. It is the most direct attitude parameter reflecting the robot's stability during cleaning in stepped areas. The tilt angle is measured in real-time by an inertial measurement unit (IMU) inside the robot. The IMU calculates the roll and pitch angles relative to gravity by integrating data from gyroscopes and accelerometers. When the robot deviates on the first step due to a lack of support in part of its body, the direction of the acceleration vector collected by the IMU changes, resulting in an increase in the roll or pitch angle. The control module, based on the IMU's attitude calculation algorithm, reads the tilt angle at predetermined time intervals and uses it as a parameter to determine whether the robot is suspended and whether the levitation thrust needs adjustment.

[0180] After obtaining the tilt angle, the levitation thrust of the underwater levitation module can be adjusted according to the tilt angle to counteract the tendency of attitude deviation through power compensation. A larger tilt angle indicates that the pool robot is more likely to tip over in the direction of suspension, in which case the underwater levitation module needs to provide greater levitation thrust to restore the body attitude. In specific implementation, the tilt angle can be converted into a levitation thrust control quantity. For example, a mapping function between the tilt angle and levitation thrust can be preset, and the current value of the tilt angle can be directly input into the mapping function to determine the next levitation thrust value based on the current tilt angle. The mapping function can be a linear function, making the tilt angle and levitation thrust grow linearly, or it can be a non-linear function, for example, using lower sensitivity in a small tilt angle range to avoid frequent adjustments, and using higher thrust gain to accelerate attitude recovery after the tilt angle exceeds a threshold. In another embodiment, the control module can also adopt a closed-loop control strategy, comparing the difference between the normal attitude angle and the current tilt angle in real time, and dynamically adjusting the levitation thrust according to the magnitude of the difference. This embodiment does not impose any special limitations on this.

[0181] By dynamically adjusting the levitation thrust of the underwater suspension module based on the tilt angle, the attitude control process of the pool robot can directly respond to changes in the body's attitude, making the control action more sensitive. The adaptive thrust adjustment process based on the tilt angle enables the pool robot to maintain a stable attitude during the cleaning of the first step surface. Even in cases where the step width is insufficient or the support boundary changes abruptly, the underwater suspension module can compensate in real time to avoid attitude loss of control, thereby improving the cleaning continuity and stability of the step area.

[0182] In one example embodiment of this disclosure, the pool robot further includes a lateral drive module, which is a power component used to provide horizontal thrust underwater. The direction of the lateral thrust generated by the lateral drive module is at a preset angle to the direction of the levitation thrust generated by the underwater levitation module. The main function of the lateral drive module is to assist the pool robot in achieving precise lateral translation in a suspended state, thereby improving its maneuverability in multi-step scenarios. For example, the lateral drive module can adopt a jet propeller or a small DC propeller structure, which uses a motor to drive the rotor to generate horizontal jet thrust. This thrust direction can form an angle greater than 0° and less than 90° with the vertical thrust direction of the underwater levitation module. In practical applications, the pool robot can calculate the current lateral offset and thrust demand in real time based on feedback data from attitude sensors and distance sensors, and output a pulse width modulation signal to the lateral drive module, so that the lateral thrust output and the vertical thrust of the underwater levitation module form a combined force control. To prevent attitude disturbances caused by the superposition of thrust in different directions, the pool robot can use a vector synthesis algorithm to dynamically allocate the output of each module, ensuring synchronous coordination between suspension balance and lateral movement.

[0183] The jet thrust direction of the lateral drive module is at a preset angle to the levitation thrust direction of the underwater suspension module. This jet thrust direction can be fixed during the structural design phase or adjusted by the control module during the operation of the pool robot; this embodiment does not impose any special limitations on this. For example, a structure with a fixed angle between the jet thrust direction of the lateral drive module and the levitation thrust direction of the underwater suspension module is suitable for symmetrically arranged dual lateral drive modules, where two lateral drive modules are installed on the left and right sides of the pool robot's body, with their jet thrust directions distributed laterally along the body. Alternatively, a structure with an adjustable angle between the jet thrust direction of the lateral drive module and the levitation thrust direction of the underwater suspension module can use a motor servo mechanism to adjust the jet thrust direction of the lateral drive module, allowing the jet angle to vary within the range of 0° to 30°, thereby providing the optimal lateral thrust direction under complex flow field conditions. The control module can automatically adjust the jet angle based on the current roll angle and step surface direction to achieve optimal energy utilization and trajectory control.

[0184] The underwater levitation module and the lateral drive module can be activated when at least part of the pool robot is suspended in the air to keep the robot's body posture stable.

[0185] When at least part of the pool robot is suspended in the air, its support area on the first step surface is reduced, and the shift in its center of gravity relative to the support boundary makes it prone to tilting towards the suspended side. At this point, activating the underwater levitation module allows it to generate a reaction thrust through the water flow from its rotors, counteracting the gravitational imbalance caused by the lack of mechanical support. This levitation thrust provides a lifting or pressure effect in the vertical direction, preventing the pool robot from suddenly tipping over due to insufficient footholds. Simultaneously, activating the lateral drive module generates a lateral stabilizing torque through its horizontal thrust, enabling the pool robot to resist the tendency to laterally tilt due to the shift in its center of gravity. For example, when the pool robot is suspended to the left, causing it to tilt to the left, the left-side lateral drive module can output a rightward thrust, which, together with the vertical stabilizing force generated by the underwater levitation module, creates a stabilizing resultant force, thus restricting the tilting tendency and improving the operational stability of the pool robot when performing cleaning tasks on narrow step areas. (Reference) Figure 11 As shown, at least part of the pool robot 210 is in a suspended state. At this time, the underwater levitation module 211 and the lateral drive module 214 on the suspended side can be activated simultaneously. Through the levitation thrust output by the underwater levitation module 211 in the vertical direction and the lateral thrust output by the lateral drive module 214 in the horizontal direction, the pool robot can resist the tendency of attitude deviation caused by the center of gravity shift in the vertical and horizontal directions, thereby ensuring that the body posture of the pool robot remains stable and avoiding falling off the steps.

[0186] By simultaneously activating the underwater levitation module and the lateral drive module, the pool robot, while suspended in mid-air, can not only counteract the tendency of its center of gravity to sink due to loss of support through vertical levitation thrust, but also counteract the tendency of its attitude to shift in the horizontal direction through lateral thrust. This allows the pool robot to achieve multi-axis stability in three dimensions during the cleaning process on the step surface. This combination of multi-force vectors enables the pool robot to maintain its attitude stability even when facing complex terrains such as abrupt changes in step boundaries, discontinuous local structures, or insufficient step width, preventing the robot from tilting, slipping, or falling off the step. This improves the cleaning safety and continuity of the pool robot in complex step areas, and enhances the cleaning coverage and cleaning effect on the step surface.

[0187] Furthermore, this disclosure also provides a method for cleaning steps for a swimming pool robot. In this embodiment, the swimming pool robot may include at least two underwater levitation modules, which are symmetrically arranged on both sides of the robot's body along its forward direction. (Refer to...) Figure 12 As shown, a step cleaning method for a pool robot may include the following steps: In step S1210, during the process of the pool robot reaching the first step surface of the step and performing a cleaning task on the first step surface, if at least part of the pool robot is in a suspended state, the underwater levitation module near the suspended side is activated to keep the body posture of the pool robot stable.

[0188] At least two underwater levitation modules can be positioned at different locations on the pool robot's body to provide distributed levitation thrust underwater. These modules can be symmetrically arranged on either side of the robot's body along its direction of travel, or they can be arranged at any two corners (front left, front right, rear left, rear right), as long as they create distinguishable levitation thrust zones in different lateral areas of the body. This embodiment does not impose any special limitations on the arrangement of the at least two underwater levitation modules. For example, with two underwater levitation modules, a symmetrical arrangement corresponds to the left and right sides of the pool robot, respectively, allowing for selective support compensation on one side when the robot becomes suspended. A diagonal arrangement allows each module to provide combined support to one side and one end simultaneously, resulting in more refined levitation control. The at least two underwater levitation modules can be independently speed-controlled by the control module, enabling differential output of levitation thrust from different locations based on the robot's attitude, thereby creating a stabilizing torque for adjusting the robot's center of gravity during attitude control.

[0189] During the process of the pool robot reaching the first step surface of the platform and performing cleaning tasks on it, the propulsion drive module can be controlled to drive the pool robot along the surface of the first step surface according to a preset cleaning path, while maintaining close contact between the cleaning components and the first step surface. The first step surface can be a straight step, an arc step, or a combination of steps with zigzag transitions. Its width and edge shape will affect the support state of the pool robot near the edge of the step. As the pool robot gradually approaches the edge, corner, or irregular step area of ​​the first step surface along the cleaning path, at least part of the robot body will begin to be suspended in the air because some tracks, wheels, or support areas gradually leave the effective support range of the first step surface.

[0190] After detecting that the pool robot is at least partially suspended, the location of the suspended side can be determined first, that is, identifying which side or corner of the pool robot near the outer side of the first step surface has lost support. The determination of the suspended side can be based on the body coordinate system and sensor arrangement results. For example, by comparing the outputs of the contact pressure sensors on the left and right sides, the side with significantly lower pressure can be considered the suspended side; alternatively, the left or right tilt of the body can be determined by analyzing the positive or negative direction of the roll angle, thus inferring the direction of suspension. After determining the suspended side, the underwater levitation module near the suspended side can be controlled. At least the underwater levitation module on the suspended side can be activated, and its rotor speed set so that the levitation thrust output by the underwater levitation module acts on the area near the suspended side of the body in a lifting manner, thereby providing additional support torque to that side. In some optional embodiments, the underwater levitation module away from the suspended side can also be activated simultaneously, except that the underwater levitation module rotates its rotor in the opposite direction, providing vertical pressure to the pool robot, causing the side of the body away from the suspended side to adhere to the first step surface.

[0191] By activating at least the underwater levitation module near the suspended side, the levitation thrust acts on the suspended body, which helps to quickly form targeted support in the tilt direction with less energy consumption, avoiding attitude oscillations caused by insufficient or excessive compensation. In areas where the width of the first step surface is insufficient or the edge of the step is irregular, this method of selecting the underwater levitation module based on the position of the suspended side allows the pool robot to maintain the stability of its body posture through hydrodynamic support and torque compensation even when part of the body exceeds the support range of the step. This ensures that the contact between the cleaning components and the first step surface is not suddenly broken, improving the continuity and safety of the step cleaning process, especially improving the cleaning effect of the pool robot in complex step scenarios.

[0192] In one example embodiment of this disclosure, while activating the underwater levitation module near the suspended side, the underwater levitation module near the non-suspended side can also be activated, so that the pool robot can form an adsorption water flow in the area near the first step surface and perform suction cleaning through the underwater levitation module; wherein, the levitation thrust direction of the underwater levitation module near the suspended side is the first direction, and the levitation thrust direction of the underwater levitation module near the non-suspended side is the second direction, and the first direction and the second direction are opposite.

[0193] The underwater levitation module near the non-suspended side can create a water pressure gradient in the local water body area on the non-suspended side through the rotor jet. This causes the water flow direction on the step surface to converge from the first step towards the jet inlet of the underwater levitation module, thus forming an adsorption water flow towards the underwater levitation module in this area. The adsorption water flow carries suspended particles, deposited dirt, and light debris into the water flow path of the underwater levitation module. For example, a filter screen can be installed in the water flow channel of the underwater levitation module to achieve the suction function during the cleaning process. On the one hand, the adsorption water flow creates a stable adhesion between the pool robot and the first step surface, allowing the non-suspended side to form a combined effect of the upward jet reaction force and the adsorption water flow, thereby enhancing the pool robot's adhesion to the step surface. On the other hand, by integrating the suction function into the underwater levitation module, the pool robot can achieve stable body posture while assisting the cleaning components in suctioning dirt from the step surface and nearby water, improving energy utilization and cleaning efficiency and effect with limited energy.

[0194] The levitation thrust direction of the underwater levitation module near the non-suspended side is the second direction. This second direction can be determined by designing the rotor installation angle of the underwater levitation module. This allows the upward jet to act on the body, generating a downward reaction pressure effect, making the non-suspended side of the body more closely adhere to the first step surface, thus enhancing the local stability support torque. This second direction can be a jet direction perpendicular to the fuselage, or it can be a slightly inclined upward jet angle depending on the structure of the underwater levitation module. For example, an angle of 10° to 20° deviating from the vertical direction of the fuselage can be selected, creating a combined effect of vertical adhesion and slight lateral convergence of the adsorbed water flow, improving the efficiency of the suction path. This embodiment does not impose any special limitations on this.

[0195] The levitation thrust direction of the underwater levitation module near the suspended side is the first direction, which is opposite to the second direction. This causes the two underwater levitation modules to output jets in opposite directions on the suspended and non-suspended sides. The first direction can be a vertically downward jet direction, so that the reaction force of the downward jet acts upward on the suspended side of the robot, thereby providing a lifting effect and compensating for the tendency of the robot to sink due to suspension. When the first direction is opposite to the second direction, the two underwater levitation modules form a jet structure with opposing force directions, so that the suspended side is lifted and the non-suspended side is pressed and adsorbed, thus forming a stable three-dimensional force balance near the step surface, ensuring that the pool robot maintains a stable posture during cleaning. The directional relationship between the first and second directions can be achieved during the design phase by adjusting the rotor direction of the two underwater levitation modules, or by controlling the reversible structure of the jet direction, allowing the system to flexibly switch force balance modes under different operating conditions. (Reference) Figure 13As shown, when the pool robot 210 is at least partially suspended, in addition to activating the underwater levitation module 211 on the suspended side to increase the upward lifting force on the pool robot 210, it can also simultaneously activate the underwater levitation module on the side away from the suspended side and spray water in the opposite direction to form an adsorption flow. At the same time, the underwater levitation module on the side away from the suspended side can also achieve the effect of suctioning dirt from the surface of the steps.

[0196] During the cleaning process achieved by activating the underwater levitation module near the non-suspended side, the underwater levitation module can employ a rotor structure with a flow guide, allowing the water flow entering the area around the rotor to be guided through a drainage channel to the waste collection chamber structure, thereby concentrating and collecting the waste carried in the adsorbed water flow. In an optional embodiment, the underwater levitation module can share the same waste discharge path with a separate suction pump, allowing the adsorbed water flow and the suction flow to merge and enter the filtration chamber together, improving waste collection efficiency. In another embodiment, the underwater levitation module can work synchronously with cleaning components, such as in conjunction with a scrubbing component, using the adsorbed water flow to quickly suck up the waste shed during the scrubbing process, further improving cleaning efficiency.

[0197] By having the underwater levitation module near the suspended side and the underwater levitation module near the non-suspended side output jets in opposite directions, a coupling torque is formed between the lifting effect in the first direction and the pressure adsorption effect in the second direction. This allows the machine to simultaneously obtain a combined stabilizing effect of upward lifting and downward adhesion near the suspended position, so that the posture no longer fluctuates significantly with the change of step width during the cleaning process. This force system arrangement allows the suspended side and the non-suspended side to obtain stabilizing forces of different natures at the same time. In areas where the width of the first step surface is insufficient, the shape of the step edge changes abruptly, or the step turns, the adhesion contact and the continuity of the suction action in the cleaning area can still be maintained, thereby improving cleaning efficiency and avoiding the risk of cleaning omissions or falls caused by unstable machine posture.

[0198] In one example embodiment of this disclosure, if the width of the pool robot is less than or equal to the width of the first step surface, at least one underwater levitation module is activated, and the levitation thrust direction of the activated underwater levitation module is the second direction, so that the pool robot forms an adsorption water flow on the first step surface and performs suction cleaning through the activated underwater levitation module.

[0199] In this case, a body width less than or equal to the width of the first step surface indicates that the pool robot can obtain complete support on the step surface, and the projection of the robot's bottom contour can fall entirely within the effective support range of the first step surface. In this situation, the pool robot has no suspended areas or only extremely small edge-to-edge suspended areas, thus eliminating the need for underwater levitation modules to provide lifting compensation. Instead, in this case, the reaction force of the water flow generated in the second direction can create a pressure adhesion effect between the body and the first step surface, allowing the pool robot to adhere more stably to the step surface.

[0200] At least one underwater suspension module can be activated, outputting vertical pressure in a second direction, which can be an upward jet along the vertical axis of the machine body. The resulting reaction force acts downward along the vertical axis of the machine body, creating a downward pressure adhesion force. Simultaneously, the underwater suspension module creates a low-pressure zone near the nozzle when jetting in the second direction, causing adjacent water to flow along the first step towards the jet inlet, forming an adsorption flow. This adsorption flow guides floating debris, loose particles, and light sediments on the first step surface into the water flow channel of the underwater suspension module. Optionally, the underwater suspension module can integrate a micro-filtration component internally, separating debris from the water through an inlet chamber, filter screen, and debris collection chamber structure; alternatively, the adsorption flow can be directed to a separate debris collection device, keeping the debris suction function independent of the water flow generation function, improving overall reliability; in another embodiment, the underwater suspension module can share a filter chamber with the main suction pump, allowing the adsorption flow to directly enter the main filtration system, improving debris interception efficiency.

[0201] By generating a pressure adhesion effect in the second direction, the underwater suspension module not only achieves the suction function but also enables the pool robot to maintain a stable attachment to the first step surface during cleaning. When the step surface has minor unevenness, uneven surface friction, or water flow disturbance, the jet in the second direction generates a downward pressure adhesion force to compensate for the attitude fluctuations caused by insufficient support or uneven friction, allowing the cleaning components to stably adhere to the surface of the first step, thus ensuring cleaning depth and continuity. In the underwater environment, due to the randomness and disturbance of water flow, the stability of the pool robot's movement may be affected. The pressure adhesion force generated by the suspension thrust in the second direction can effectively suppress these disturbances, making the movement trajectory of the pool robot on the first step surface smoother, improving the controllability and accuracy of the cleaning path, thereby increasing the cleaning coverage of the step surface. At the same time, the simultaneous operation of attitude stability and suction function can also improve the overall cleaning effect of the step area and improve energy utilization.

[0202] In one example embodiment of this disclosure, the pool robot may include at least two lateral drive modules, the installation positions of the lateral drive modules being adapted to the installation positions of the underwater suspension modules, and the lateral thrust generated by the lateral drive modules being at a preset angle to the suspension thrust generated by the underwater suspension modules.

[0203] At least two lateral drive modules can be symmetrically arranged on both sides of the robot's body along its direction of travel, or arranged in a four-point configuration (left, right, front, and back), as long as they can create at least two independent points of lateral thrust around the robot. Multiple lateral drive modules are controlled independently or in conjunction with a control module, allowing different modules to output lateral thrust of varying magnitudes and directions as needed. This provides adjustable lateral attitude control and path correction capabilities during cleaning in stepped areas.

[0204] The matching of the installation positions of the lateral drive module and the underwater suspension module means that their arrangement on the body is designed in a coordinated manner so that the suspension thrust provided by the underwater suspension module and the lateral thrust provided by the lateral drive module can form a spatial combination conducive to attitude stability in terms of torque. This matching can be achieved by placing the lateral drive module and the underwater suspension module in the same side region; or by arranging the lateral drive module on the same or mirror image of the underwater suspension module in the front-rear direction of the body, so that the two modules form a relatively uniform torque distribution around the center of gravity of the pool robot. In an optional embodiment, each underwater suspension module and its corresponding lateral drive module can be paired and arranged in the same mounting compartment or the same side wall region. In this way, the power unit composed of the underwater suspension module and the lateral drive module can be used as a composite execution unit during control. When a tendency to suspend or attitude deviation is detected on that side, the underwater suspension module can output suspension thrust for lifting or pressing, and the lateral drive module can output lateral thrust for lateral attitude correction, thus forming a comprehensive stable force field on that side.

[0205] The lateral thrust generated by the lateral drive module and the levitation thrust generated by the underwater levitation module form a preset angle. This means that the angle between their force vectors is predetermined during the design phase, allowing them to form a cross-distributed force system on the robot body during operation, thereby achieving joint attitude control in three-dimensional space. The preset angle can be 90 degrees or approximately 90 degrees, making the lateral thrust and levitation thrust orthogonal in space. One direction is responsible for vertical lifting or pressing, while the other direction is responsible for horizontal contact or lateral correction, facilitating the decomposition of vertical attitude control and horizontal position control in the control algorithm. Alternatively, other angles greater than zero and less than 180 degrees can be selected, such as 60 degrees or 120 degrees, so that the force vectors form a certain angle between vertical and horizontal, thereby creating a coupling effect on the robot's attitude and position simultaneously with a single thrust output, adapting to the control requirements of special shapes or specific water flow environments.

[0206] By maintaining a preset angle between the lateral thrust direction and the suspension thrust direction, when the pool robot is partially suspended, tilted, or shifted in position near the first step surface, the control module can coordinate the output of the underwater suspension module and the lateral drive module based on this stable mechanical configuration. This enables comprehensive control of the robot's posture and relative position to the step, allowing the pool robot to maintain stable walking and edge cleaning even in complex step structures and underwater disturbance environments. This improves the complete cleaning coverage of the step surface and ensures effective cleaning of the step area in complex step scenarios.

[0207] It should be noted that although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.

[0208] Furthermore, this disclosure also provides a pool robot, as shown in the following embodiments. Figure 14 As shown, the pool robot 210 may include a robot body 212, a propulsion drive module 213, an underwater levitation module 211, and a control module (not shown in the figure). Wherein: The robot body 212 is the basic load-bearing structure for installing and supporting the propulsion module 213, the underwater levitation module 211, the control module 440, and other functional components, while also serving as the encapsulated shell in contact with the external water body. The robot body 212 can be a hollow shell structure, made of waterproof and corrosion-resistant materials such as ABS engineering plastic, polycarbonate, or metal with an anti-corrosion coating. The internal cavity space is formed through injection molding or sealed assembly to house motors, batteries, control circuit boards, and cables. The robot body's shape can be designed as a streamlined, square, or near-rectangular structure according to the pool environment and hydrodynamic characteristics to reduce water resistance while ensuring sufficient internal space. The robot body's center of gravity and center of buoyancy are matched through structural arrangement and counterweight modules, enabling the pool robot to maintain a near-horizontal posture when stationary and at low speeds, providing a stable mechanical foundation for the coordinated control of the underwater levitation module and the propulsion module. The surface of the robot body can also integrate handles, guardrails, and buffer rubber strips to improve handling convenience and reduce impact when colliding with pool walls or steps.

[0209] The travel drive module 213 can be located on both sides of the robot body to drive the robot body to move forward. The travel drive module can be one or more combinations of tracked drive, wheeled drive, or integrated brush roller drive structure, and this embodiment is not limited to these. Taking tracked drive as an example, the travel drive module can include a drive motor, a reduction mechanism, a drive wheel, a driven wheel, and a track assembly surrounding it. The drive motor can be a DC brushless motor, and the output torque of the motor is amplified and transmitted to the drive wheel through a gear reduction or planetary reduction mechanism, driving the track to circulate along one side of the robot body, thereby generating frictional traction between the track and the bottom of the pool or the step surface, realizing the forward and backward movement of the robot body. To adapt to the edge of the step and the surface roughness, the outer surface of the track can be designed with a structure with raised ribs or flexible ridges to improve adhesion and reduce the probability of slippage. For wheeled drive structures, the travel drive module can include multiple rubber-coated drive wheels, achieving traction through the contact of tire treads with the step surface. For integrated brush roller drive structures, the travel drive module can convert the rotational power of the cleaning brush roller into travel thrust, allowing cleaning and travel to share the transmission system under certain working conditions. The travel drive module is connected to the robot body via sealed bearings and a waterproof structure, and the internal motor cables are connected to the control module circuit board via waterproof connectors, ensuring long-term reliable operation in underwater environments. Under the control of the control module, the travel drive module, in conjunction with the underwater levitation module, can achieve various movement modes within the step area, including forward movement, fine-tuning, crawling, and edge-hugging.

[0210] The underwater levitation module 211 can be mounted on the robot body 212 to provide underwater levitation thrust, enabling the pool robot 210 to remain in a levitation state and controlling its attitude. In an optional embodiment, the underwater levitation module may include a rotor assembly, a motor assembly, a flow guide, and a mounting hole mating structure. The rotor assembly rotates at high speed under the drive of the motor, forming a directional jet stream in the surrounding water. The reaction force of the water generates a vertical or near-vertical levitation thrust on the robot body, compensating for buoyancy and gravity. The underwater levitation module can be installed in a pre-set mounting hole or mounting channel on the robot body, and is fixedly connected to the robot body by a mounting base, a sealing ring, and fasteners. The diameter of the mounting hole and the rotor speed of the underwater levitation module are maintained within a specific ratio range to ensure that the jet stream forms a relatively stable flow field in a narrow space, thereby providing stable levitation capability in the stepped area. The control module can adjust the motor speed of the underwater levitation module through pulse width modulation signals to achieve precise control over the magnitude and direction of the levitation thrust, enabling the pool robot to perform levitation approach, levitation landing, and step-crossing movements according to changes in the width and height of different steps.

[0211] The control module can be located inside the robot body 212 to execute cleaning methods for the pool robot. In some alternative embodiments, the control module may include a processor, power management circuitry, memory, drive circuitry, and interface circuitry connected to the propulsion drive module, underwater levitation module, and sensing module. The processor can be a microcontroller unit (MCU) or a system-on-chip (SoC). The memory pre-stores control programs and parameters for executing the step cleaning method for the pool robot. During operation, the processor calls the control program to calculate and fuse data collected from inertial measurement units, depth sensors, distance sensors, and attitude sensors, etc., to generate control commands for the propulsion drive module and underwater levitation module.

[0212] For example, when executing the control program, the control module can schedule the pool robot to travel to the starting point of the step based on the step's position information and the global cleaning path. Then, using an underwater levitation module, the pool robot levitates and lands on the first step. Under different step widths and landing strategies, the module controls the pool robot to complete levitation landing, attitude adjustment, and step-crossing movement. During step cleaning, the control module can plan a local cleaning path based on the step contour information of the first step surface. Using the position where the pool robot levitates and first lands on the first step surface as the starting position, the module drives the movement drive module to perform the cleaning task along the cleaning path. When it detects that the first step surface is cleaned but there is still an uncleaned second step surface, the underwater levitation module levitates the pool robot and lands it at the starting position of the second step surface, thus achieving continuous cleaning across multiple steps.

[0213] In an optional implementation, the control module may further include a wireless communication unit for data interaction with an external host computer or mobile terminal, enabling extended functions such as working mode configuration, parameter distribution, cleaning status monitoring, and fault diagnosis. The control module can also be combined with a safety strategy module to trigger a fall recovery process when the pool robot is detected to have fallen from the first or second step surface. This process drives the pool robot back to the starting point of the corresponding step surface and restores it to its suspended position via the underwater levitation module, ensuring the complete execution of the cleaning task in the step area.

[0214] In an example embodiment of this disclosure, reference continues to be made to Figure 14 As shown, the pool robot 210 may also include a lateral drive module 214 disposed on the robot body 212, wherein the lateral thrust generated by the lateral drive module 214 is at a preset angle to the levitation thrust generated by the underwater levitation module 211.

[0215] The lateral drive module provides horizontal or oblique thrust when the pool robot is in an aquatic environment, assisting the robot in making precise position adjustments, maintaining contact with the step surface, correcting hovering drift, or performing lateral displacement movements within stepped areas. The lateral drive module can employ a micro-jet propeller, a lateral propeller, or a water pump side-jet structure; this embodiment is not limited to these. The lateral drive module can utilize the momentum exchange of water to generate a reaction force to produce lateral displacement force. The installation angle between the lateral drive module and the robot body can be determined based on the structural design. The direction of its output lateral thrust forms a preset angle with the direction of the underwater levitation module's levitation thrust. For example, in an optional embodiment, this preset angle can be set to 90 degrees or approximately 90 degrees to ensure that levitation control and lateral movement control are mechanically independent, thereby achieving higher attitude stability and position control accuracy.

[0216] In one embodiment, the lateral drive module can be located on only one side of the robot body, or it can be symmetrically arranged on both sides to form a dual-sided lateral thrust output structure. A single-sided output structure can be used for lightweight lateral adjustment, while a dual-sided output structure can utilize thrust difference to achieve lateral movement, steering assistance, and even small yaw angle adjustments. The lateral drive module can be connected to the control module via an electrical interface. The control module controls the motor speed of the lateral drive module through pulse width modulation signals, allowing the lateral thrust magnitude to be adjusted within a continuous range. The direction of the lateral thrust can be achieved by reversing the motor or switching between multiple injection channels. In an optional embodiment, the lateral drive module can be equipped with a bidirectional jet structure, controlling the water outlet through mechanical or electronic valves to achieve rapid thrust direction switching. When the lateral drive module operates in water, its structure needs to have good waterproof sealing. The motor cavity can be protected by resin potting or a fully sealed rubber ring structure to prevent corrosion or short circuits caused by prolonged underwater immersion.

[0217] When the lateral drive module and the underwater levitation module work together, the control module dynamically adjusts the thrust distribution between them by integrating data from the inertial measurement unit, depth sensor, and distance sensor. This enables the pool robot to perform various precise positional maneuvers in three-dimensional space. For example, when the pool robot needs to approach the first step surface laterally while levitating, the underwater levitation module maintains its levitation height and basic posture, while the lateral drive module provides lateral thrust, allowing the pool robot to translate horizontally. This method allows the pool robot to stay close to the edge of the step without rubbing against it, and also avoids body vibration caused by sudden changes in height at the step edge.

[0218] By incorporating the lateral drive module, the pool robot gains direct control over lateral displacement during step cleaning tasks. When hovering between multiple steps, the lateral drive module helps the robot translate towards the target step surface with less disturbance, making the landing process more stable. In complex step contours or curved surfaces, the lateral drive module can provide auxiliary attitude correction, making the thrust adjustment process of the underwater suspension module more precise, thereby improving the robot's overall controllability and cleaning continuity in the step area.

[0219] In an optional embodiment of this disclosure, the pool robot may include at least two underwater levitation modules, which are symmetrically arranged on both sides of the robot's body along its direction of travel. (See reference...) Figure 15 As shown, taking the pool robot 210, which includes two underwater levitation modules 211 as an example, the two underwater levitation modules 211 are symmetrically arranged on both sides of the body along the forward direction (such as the X-axis direction) of the pool robot 210.

[0220] In a pool robot comprising at least two underwater levitation modules, these modules are symmetrically positioned on either side of the robot's body along its forward direction (e.g., the X-axis). The arrangement of multiple underwater levitation modules allows for a symmetrical distribution of levitation thrust along the robot's left-right axis, providing greater attitude controllability and stronger resistance to disturbances while suspended. These modules can be arranged symmetrically, for example, with one or more modules on each side, forming a mirror image on either side of the robot's transverse centerline. This symmetrical arrangement ensures that when the robot is in a horizontal position, the underwater levitation modules on both sides output equal and consistent levitation thrust, creating a vertical resultant force that achieves stable buoyancy, descent, or sustained suspension. When roll or pitch angle control is required, the control module can adjust the thrust difference between the left and right underwater levitation modules to allow the robot to adjust its angle around the longitudinal or transverse axis, enabling real-time, precise attitude control.

[0221] In one embodiment, the rotor diameter, fairing structure, and jet direction of multiple underwater levitation modules can be designed to be consistent to ensure that the flow field distribution characteristics generated on the left and right sides are the same, reducing attitude deviation caused by hydrodynamic asymmetry. In another alternative, the power levels of the multiple underwater levitation modules can be different to adapt to the positioning control requirements under different robot sizes or different step structures. The multiple underwater levitation modules can be connected to the robot body structure through mounting holes. The diameter of the mounting holes of each underwater levitation module is kept consistent with the ratio of the rotor speed to ensure that the multiple underwater levitation modules can maintain the same level of turbulence when operating underwater, thereby achieving coordinated control.

[0222] In another optional embodiment of this disclosure, reference is made to Figure 16 As shown, the pool robot 210 may include four underwater levitation modules 211, with each pair of underwater levitation modules 211 symmetrically arranged on both sides of the body along the forward direction (such as the X-axis direction) of the pool robot 210.

[0223] The four underwater levitation modules give the pool robot enhanced three-dimensional attitude control capabilities, enabling more precise levitation and landing, as well as movement across steps, in complex stair areas. These four modules can be positioned on the front left and right sides and the rear left and right sides of the robot body, forming a symmetrical, paired layout. When the two front and two rear underwater levitation modules output the same thrust, the pool robot can achieve stable vertical levitation. When a thrust difference exists between the two pairs of front and rear underwater levitation modules, the robot can pitch around its horizontal axis, used for front-to-back balance adjustments as it approaches steps. When a thrust difference exists between the two pairs of left and right underwater levitation modules, roll angle control around the longitudinal axis is achieved, used for levitation translation or phased landing on steps that are too narrow. The layout of the four underwater levitation modules can also achieve a certain degree of yaw angle adjustment. For example, by forming a thrust combination with the underwater levitation module in the front left direction and the underwater levitation module in the rear right direction, and forming another thrust combination with the underwater levitation modules in the front right direction and the underwater levitation module in the rear left direction, the control module can generate a small rotation around the vertical axis through the thrust difference, so that the robot can complete the direction fine adjustment in the levitation state, so as to accurately align with the starting position of the step or compensate for drift.

[0224] The configuration of multiple or four underwater levitation modules enables the pool robot to achieve greater attitude stability, stronger anti-disturbance capabilities, and more flexible landing control in stepped areas. Multiple underwater levitation modules can provide precise thrust compensation under complex conditions such as water disturbance, irregular step shapes, insufficient step width, or partial robot suspension, allowing the pool robot to achieve stable hovering approach, hovering movement, and hovering landing in confined spaces. This significantly improves the adaptability and controllability when performing cleaning tasks in stepped areas. Simultaneously, the four-module layout, while ensuring the manufacturing cost of the pool robot, can further improve the redundancy and accuracy of three-dimensional attitude control, giving the pool robot higher reliability and cleaning coverage when traversing multiple steps or handling structurally complex step surfaces.

[0225] The specific details of the aforementioned pool robot have been described in detail in the corresponding step cleaning method for pool robots, so they will not be repeated here.

[0226] It should be noted that although several modules or units of the pool robot have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0227] Furthermore, the above figures are merely illustrative of the processes included in the method according to exemplary embodiments of this disclosure and are not intended to be limiting. It is readily understood that the processes shown in the above figures do not indicate or limit the temporal order of these processes. Additionally, it is readily understood that these processes may be executed synchronously or asynchronously, for example, in multiple modules.

[0228] From the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solutions according to the embodiments of this disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, touch terminal, or network device, etc.) to execute the methods according to the embodiments of this disclosure.

[0229] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and embodiments are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the claims.

[0230] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A method for cleaning steps using a swimming pool robot, characterized in that, The pool robot includes an underwater levitation module, and the method includes: The underwater levitation module allows the pool robot to levitate and land on the first step of the steps, and clean the steps. The underwater levitation module is disposed in the mounting hole of the swimming pool robot body. During the process of the swimming pool robot levitation and landing on the first step surface, the ratio of the diameter of the mounting hole to the rotor speed of the underwater levitation module is 0.0133mm / (r / min)-0.08mm / (r / min).

2. The method according to claim 1, characterized in that, The process of suspending the pool robot on the first step surface of the steps via the underwater levitation module includes: The pool robot is suspended in a levitating state by activating the underwater levitation module; Control the levitation thrust of the underwater levitation module to make the swimming pool robot in the levitation state reach the target roll angle, and drive the swimming pool robot at the target roll angle to move laterally towards the first step surface; When the robot detects that it has approached the first step surface, it controls the pool robot to land on the first step surface.

3. The method according to claim 2, characterized in that, Controlling the pool robot to land on the first step surface includes: When the pool robot hovers and moves to directly above the first step surface at the target roll angle, the levitation thrust of the underwater levitation module is adjusted to switch the pool robot from the target roll angle posture to a horizontal posture, and the horizontally positioned pool robot is controlled to land on the first step surface; or, When the pool robot hovers and moves to directly above the first step surface at the target roll angle, after controlling one side of the pool robot at the target roll angle to land on the first step surface, the levitation thrust of the underwater levitation module is adjusted so that the other side lands on the first step surface.

4. The method according to claim 1, characterized in that, The pool robot includes a lateral drive module, and the lateral thrust generated by the lateral drive module is at a preset angle to the levitation thrust generated by the underwater levitation module. The process of suspending the pool robot on the first step surface of the steps via the underwater levitation module includes: The pool robot is suspended in a levitating state by activating the underwater levitation module; When the swimming pool robot, which is in a suspended state, reaches the target position, the lateral drive module is activated to make the swimming pool robot translate and move closer to the first step surface; When the robot detects that it has approached the first step surface, it controls the pool robot to land on the first step surface.

5. The method according to any one of claims 1 to 4, characterized in that, Controlling the pool robot to land on the first step surface includes: When the width of the first step surface is greater than or equal to the body width of the pool robot, the pool robot is driven to suspend directly above the first step surface by the underwater levitation module, and the entire projection area of ​​the pool robot on the first step surface is within the first step surface. At this time, the pool robot is controlled to land on the first step surface.

6. The method according to claim 1 or 2, characterized in that, Controlling the pool robot to land on the first step surface includes: When the width of the first step surface is less than the width of the pool robot's body, the pool robot is driven to levitate directly above the first step surface by the underwater levitation module, and the projection area of ​​the pool robot on the first step surface covers the entire width range of the first step surface. At this time, the pool robot is controlled to land on the first step surface.

7. The method according to claim 6, characterized in that, Controlling the pool robot to land on the first step surface includes: Adjust the levitation thrust of the underwater suspension module so that the pool robot approaches the first step surface at the target roll angle. At this time, the body of the pool robot that is close to the inside of the first step surface lands on the first step surface first. The inner side of the first step surface is the side away from the side of the pool robot that is suspended on the first step surface.

8. The method according to claim 1, characterized in that, Before suspending the pool robot via the underwater levitation module and placing it on the first step surface of the step, the method further includes: Obtain the location information of the steps and the global cleaning path of the steps; The pool robot is driven to the starting point of the steps based on the global cleaning path. The starting point is located at one end of the step area near the top or bottom step.

9. The method according to claim 8, characterized in that, The underwater levitation module suspends the pool robot and places it on the first step surface of the steps, including: When the starting point is located at the end closest to the top step, the step surface of the top step is the first step surface. The underwater levitation module causes the pool robot to levitate downwards and land at the starting position of the first step surface of the step. When the starting point is located at the end closest to the bottom step, the step surface of the bottom step is the first step surface. The underwater levitation module causes the pool robot to levitate upward and land at the starting position of the first step surface of the step. Specifically, when the pool robot is suspended downwards, the levitation thrust of the underwater levitation module is less than the levitation thrust when it is suspended upwards.

10. The method according to claim 1, characterized in that, The method further includes: Obtain the step contour information of the first step surface; The local cleaning path of the pool robot on the first step surface is planned based on the step contour information; The local cleaning path includes the starting and ending positions of the cleaning path of the pool robot on the first step surface, with the starting position being the position where the pool robot suspends and first lands on the first step surface.

11. The method according to claim 1, characterized in that, The method further includes: When the first step surface is cleaned, if a second step surface that has not been cleaned is detected, the end point of the cleaning process on the first step surface is taken as the new starting point. The new starting point is the starting point for cleaning the uncleaned area on the step, and the pool robot is suspended and landed on the starting point of the second step surface by the underwater suspension module.

12. The method according to claim 1, characterized in that, The method further includes: If the pool robot is detected to have fallen off the first step, it will be driven back to the starting point corresponding to the first step, which is the starting position for cleaning the uncleaned area on the step. After the pool robot is suspended and landed at the starting position on the first step by the underwater levitation module, it will continue to perform the cleaning task on the first step.

13. The method according to claim 1 or 12, characterized in that, The method further includes: If the pool robot is detected to have fallen from the first step, the underwater levitation module will cause the pool robot to levitate back to its original position before the fall, and then continue to perform the cleaning task on the first step after returning to the original position.

14. A swimming pool robot, characterized in that, include: The robot itself; A travel drive module is located on both sides of the robot body and is used to drive the robot body to move forward. An underwater levitation module is installed on the robot body to provide underwater levitation thrust to the robot body so that the pool robot is in a levitation state and to control the attitude of the pool robot in the levitation state. A control module, disposed inside the robot body, is used to perform the cleaning method for a pool robot as described in any one of claims 1-12.

15. The pool robot according to claim 14, characterized in that, The pool robot also includes: A lateral drive module is mounted on the robot body, and the lateral thrust generated by the lateral drive module is at a preset angle to the levitation thrust generated by the underwater levitation module.

16. The pool robot according to claim 14, characterized in that, The pool robot includes at least two underwater levitation modules, which are symmetrically arranged on both sides of the robot's body along its direction of travel; or The pool robot includes four underwater levitation modules, with every two underwater levitation modules symmetrically arranged on both sides of the body along the direction of the pool robot's movement.

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