Hexapod robot with amphibious function

Abstract

The invention belongs to the technical field of mobile robots, and particularly relates to an amphibious hexapod robot which comprises a robot body, six walking feet, a protection box, propellers, a multi-sensor system and a central control unit. The six walking feet are arranged on the two sides of the robot body, and a waterproof driving joint is arranged at the tail end of each foot. The protection box is arranged at the root of the walking foot and internally integrated with propellers; the sensor system comprises a water depth sensor, an attitude sensor and a grounding detection module; the central control unit is used for collecting sensor data in real time, judging whether the current environment is a land or a water area, automatically switching a walking mode or a water propulsion mode, and meanwhile adaptively adjusting gaits and the rotating speed of propellers according to the water depth and the terrain. The robot has environment perception, mode decision, gait generation, grounding prevention protection and energy optimization strategies, full-autonomous and high-adaptability movement in the land and water environment is achieved, and the working capacity and safety of the robot in the complex environment are improved.

Description

Technical Field

[0001] This invention relates to the field of mobile robot technology, and in particular to a hexapod robot with amphibious capabilities. Background Technology

[0002] Traditional hexapod robots are mostly used for movement on structured or unstructured terrestrial terrain, and their control strategies are mainly based on gait planning and terrain adaptation. However, in aquatic environments, most common underwater robots use propeller propulsion and lack the ability to walk on land. In recent years, amphibious robots have gradually become a research hotspot, but existing solutions often have the following problems:

[0003] Mode switching relies on manual or simple threshold judgments and cannot make dynamic decisions based on the real-time environment; it has poor adaptability to water-land transition areas and is prone to jamming, slipping, or low propulsion efficiency; it lacks anti-bottoming and anti-collision protection and is easily damaged in complex underwater terrain; energy management is crude and does not combine environment and task for dynamic power consumption optimization; the control algorithm and hardware are highly coupled and it is not easy to reproduce and migrate on different models.

[0004] Therefore, there is an urgent need for an amphibious hexapod robot with intelligent perception, autonomous decision-making, and adaptive control to cope with complex and ever-changing working environments. Summary of the Invention

[0005] Based on the technical problems existing in the prior art, this invention proposes a hexapod robot with amphibious capabilities.

[0006] The present invention proposes a hexapod robot with amphibious capabilities, comprising:

[0007] The aircraft comprises a fuselage, six walking legs, a protective housing, a propeller, a multi-sensor system, and a central control unit. The six walking legs are symmetrically arranged on both sides of the fuselage, with a waterproof drive joint at the end of each leg. The protective housing is located at the base of the walking legs and integrates a propeller for water propulsion. The multi-sensor system includes a depth sensor, an attitude sensor, and a bottom-touching detection module. The central control unit is used to collect sensor data in real time, determine whether the current environment is land or water, and automatically switch between walking mode and water propulsion mode.

[0008] The robot body is made of lightweight waterproof composite material, and integrates a battery compartment, control board, and communication module. The walking legs adopt a two-stage linkage structure, and the waterproof drive joints are equipped with brushless motors and harmonic reducers, providing torque output and position feedback functions. The water depth sensor is pressure type (range 0~50m, accuracy ±0.1m), and the attitude sensor integrates a three-axis gyroscope, accelerometer, and magnetometer. The central control unit adopts an embedded industrial computer with a real-time operating system. The integrated design of the hardware system enables compatibility between land walking and water propulsion functions. The waterproof drive joints and lightweight body meet the protection and mobility requirements of aquatic and terrestrial environments. The collaboration of multiple sensors and the central control unit allows the robot to complete environmental judgment and mode switching without human intervention, greatly improving the autonomous operation in complex environments.

[0009] Preferably, the protective box is an openable and closable structure, which is closed in land mode to protect the propeller and opened in water mode to expose the propeller.

[0010] The protective box preferably adopts a shuttle-shaped design, with filter baffles at the front and rear ends of the exterior, corresponding to the front and rear cover structure inside. In land mode, the front and rear covers automatically close to prevent the intrusion of mud, sand, and gravel. In water mode, the covers open simultaneously, allowing the propeller to rotate without obstruction. The filter baffles can further intercept aquatic plants and debris in the water, preventing them from entangled in the propeller blades. The openable and closable structure resolves the contradiction between propeller "protection" and "efficient propulsion". The filter baffles enhance adaptability to complex environments, avoiding wear and tear on the propeller in land environments while ensuring the stability of propulsion in water, extending the service life of core components, and reducing maintenance costs.

[0011] Preferably, the bottom contact detection module includes a pressure sensor and an ultrasonic ranging unit located at the end of the walking foot, used to detect whether it has contacted the bottom of the water or an obstacle;

[0012] The trigger threshold of the pressure sensor is set to 10N, which can accurately identify the contact state between the foot and the ground or the bottom of the water; the ultrasonic ranging unit has an accuracy of centimeters and outputs the distance data from the bottom of the water or obstacles in real time. The data from both are transmitted synchronously to the central control unit for fusion and judgment. Effect description: The dual detection mechanism avoids the risk of misjudgment by a single sensor. The pressure sensor ensures the recognition of ground contact and the perception of shallow water bottoms, while the ultrasonic unit provides early warning of obstacles at a distance, providing reliable data support for the anti-bottoming and anti-collision strategies and reducing damage to the robot in complex terrain.

[0013] Preferably, the central control unit is also connected to a visual sensor and an inertial measurement unit for constructing a local environment map and real-time attitude estimation.

[0014] The visual sensor uses an RGB-D camera to collect environmental point cloud data; the inertial measurement unit outputs the robot's angular velocity and linear acceleration information, which are complemented and filtered with the attitude sensor data to accurately calculate attitude parameters such as pitch and roll angles; the central control unit constructs a local environment map through data fusion algorithms to reconstruct terrain undulations and obstacle distribution; the local environment map allows the robot to clearly understand the surrounding environment, and real-time attitude estimation ensures that the robot maintains balance when switching between land and water, avoiding rollover, and provides accurate basis for gait adjustment and propeller differential speed control, significantly improving the stability and safety of the movement process.

[0015] Preferably, the central control unit adaptively adjusts the walking gait and propeller speed according to water depth and terrain information, and implements a bottom-touching protection strategy;

[0016] Water depth data is processed by moving average filtering, and terrain information is acquired collaboratively by a visual sensor and a bottom-touching detection module. In land mode, step frequency and step height are adjusted using the CPG algorithm, while in water mode, propeller differential speed is calculated based on heading deviation. The anti-bottom-touching protection strategy is automatically triggered when the water depth is <0.5m or the distance from the bottom is <0.3m. The adaptive adjustment capability allows the robot to adapt to land terrain with different slopes and roughness and water environments with different depths, avoiding jamming, slipping, or low propulsion efficiency caused by improper gait. The anti-bottom-touching strategy further reduces the risk of underwater operations and improves the adaptability to complex environments.

[0017] Preferably, the anti-bottom-out protection strategy includes: automatically raising the fuselage height or adjusting the propeller pitch angle when approaching the bottom of the water is detected;

[0018] The robot's height is increased by adjusting the angle of its foot joints, with the maximum increase limited by the robot's structural design. The propeller pitch angle is adjusted according to a formula. If the height adjustment reaches its limit and the risk of bottoming out is not eliminated, the robot will reduce its propulsion power or enter a hovering state and upload alarm information. The tiered and progressive protection strategy provides a comprehensive response to the risk of bottoming out, from height adjustment to attitude optimization to power control, progressively avoiding collision damage. The alarm function allows operators to monitor the risk status in real time, taking into account both autonomous operation and emergency intervention needs.

[0019] Preferably, the central control unit also executes an energy optimization strategy, dynamically allocating the power of the joint motors and propellers according to the current mode and task load;

[0020] The energy optimization strategy is based on deep reinforcement learning (PPO algorithm). The state space includes mode type, water depth, attitude angle, task load level and remaining battery power. The motion space is the power allocation ratio of 8 actuators (6 joint motors + 2 propellers). The reward function weights are set as w1 (energy consumption), w2 (stall penalty), and w3 (collision penalty). The power allocation scheme is updated every 10 seconds. Dynamic power allocation avoids energy waste and can achieve optimal energy consumption configuration in land walking, water propulsion and transition modes. It not only ensures that the operation performance meets the task requirements, but also extends the battery life and improves the robot's continuous operation capability.

[0021] Preferably, the energy optimization strategy is based on a deep reinforcement learning model, with the goal of minimizing total energy consumption, and outputs the optimal power allocation ratio for each actuator.

[0022] Preferably, the intelligent amphibious hexapod robot also includes a communication module for receiving remote commands and uploading environmental data and system status. The communication module supports bidirectional data transmission and can upload information such as water depth, terrain, attitude, remaining battery power, and mode status to a remote monitoring terminal in real time. At the same time, it can receive remote control commands from operators, enabling flexible switching between autonomous operation and remote intervention. The communication module broadens the robot's operating scenarios, and is especially suitable for remote control in dangerous environments (such as deep water areas and complex terrain). Operators can monitor the operating status in real time and quickly intervene to make adjustments in special circumstances, which not only ensures operational safety but also improves operational convenience.

[0023] Preferably, the walking foot adopts a two-section linkage structure, and the joint is equipped with a sealing ring and a drain valve, which has underwater pressure resistance and self-drainage capabilities;

[0024] The two-stage linkage structure, combined with a harmonic reducer, can output sufficient torque and achieve precise position feedback. The sealing ring is made of water-resistant and corrosion-resistant material to prevent water from seeping into the joint motor. The drain valve automatically opens after the robot leaves the water to drain residual water from the joint, ensuring underwater pressure resistance and adaptability to water depths of 0-50m. The two-stage structure balances flexibility and load-bearing capacity. The sealing ring and drain valve solve the pain points of waterproofing and drainage in underwater operations, preventing joint corrosion or failure due to water ingress. This ensures that the walking legs can work stably in both aquatic and terrestrial environments, improving the overall reliability and service life of the robot.

[0025] Compared with the prior art, the present invention provides a hexapod robot with amphibious capabilities, which has the following advantages:

[0026] 1. Cross-environment compatibility, solving the shortcomings of traditional robots: Through the hardware combination of "two-stage waterproof walking legs + openable and closable protective box + integrated propeller", a seamless connection between land walking and water propulsion is achieved: In land mode, the walking legs adapt to unstructured terrain through waterproof drive joints (brushless motor + harmonic reducer), and in water mode, the protective box opens and the propeller propels efficiently, making up for the shortcomings of traditional hexapod robots "cannot go into water" and underwater robots "cannot move on land". It can cope with complex scenarios in water-land transition areas (such as shallow water, swamps, and shore waters) and avoid problems such as getting stuck and slipping.

[0027] 2. Adaptive transition zone design enhances maneuverability: For water-land boundary environments (water depth 0.1~0.3m), a hybrid control strategy of "partial foot paddling + propeller micro-propulsion" is designed, which can smoothly complete the mode transition without human intervention. Compared with the existing amphibious robot solution that "relies on human operation for transition", it greatly improves the passability of complex terrain.

[0028] 3. Multi-sensor fusion ensures accurate and reliable environmental assessment. The multi-sensor system (depth sensor + attitude sensor + bottom contact detection module + vision sensor + inertial measurement unit) forms a "data complementarity verification" mechanism: the pressure-type depth gauge (accuracy ±0.1m) accurately identifies the water depth, the foot pressure sensor (threshold 10N) + ultrasonic ranging unit (centimeter-level accuracy) dually detects bottom contact / obstacles, the vision sensor (RGB-D camera) constructs a local environmental map, and the inertial measurement unit optimizes attitude estimation (pitch angle, roll angle), avoiding misjudgment by a single sensor, and significantly improving the accuracy of environmental condition assessment.

[0029] 4. Real-time dynamic decision-making with high operational autonomy: The central control unit achieves automatic mode switching based on a "finite state machine": when it detects "water depth < 0.2m and 3 feet above touching the ground" for 2 seconds, it automatically switches to land CPG gait mode; when "water depth ≥ 0.2m and no foot touches the ground", it switches to water propeller differential control mode. No manual threshold setting or remote control is required, which meets the needs of fully autonomous operation (such as field exploration and disaster relief). Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the overall structure of a hexapod robot with amphibious capabilities proposed in this invention.

[0031] Figure 2 This is a schematic diagram of the walking leg structure of a hexapod robot with amphibious capabilities proposed in this invention.

[0032] Figure 3 This is a block diagram of the control system structure of a hexapod robot with amphibious capabilities proposed in this invention.

[0033] Figure 4 This is a flowchart of the environmental perception and pattern decision-making process of the present invention.

[0034] In the diagram: 100, fuselage; 200, walking legs; 210, waterproof drive joint; 300, protective case; 400, filter plate; 500, multi-sensor system; 510, depth sensor; 520, attitude sensor; 530, bottom contact detection module; 531, pressure sensor; 532, ultrasonic ranging unit; 540, vision sensor; 550, inertial measurement unit; 600, central control unit. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0036] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0037] Example 1: Structure and Hardware Configuration of a Hexapod Robot

[0038] like Figure 1-3 As shown, the intelligent amphibious hexapod robot provided by the present invention includes a body 100, six walking legs 200, a protective box 300, a propeller, a multi-sensor system 500, and a central control unit 600.

[0039] The body 100 is made of lightweight waterproof composite material and houses the battery compartment, control board and communication module. Six walking legs 200 are symmetrically distributed on both sides of the body. Each leg adopts a two-stage linkage structure and has a waterproof drive joint 210 at the joint. The drive method is a brushless motor + harmonic reducer, which has torque output and position feedback functions.

[0040] The protective box 300 is located at the heel of the walking foot and is preferably an openable and closable spindle-shaped structure. It integrates a propeller inside and has filter baffles 400 at the front and rear positions on the outside. The positions of the two filter baffles 400 correspond to the front and rear covers inside the protective box 300, respectively, to prevent foreign objects from entering the protective box 300 and damaging the propeller. In water mode, the front and rear covers inside the protective box 300 automatically open and the propeller operates; in land mode, the front and rear covers inside the protective box 300 close to prevent mud and sand from entering.

[0041] Sensor system 500 includes:

[0042] 510 water depth sensor: adopts a pressure-type water depth gauge, with a range of 0~50m and an accuracy of ±0.1m;

[0043] Attitude Sensor 520: Integrates a three-axis gyroscope, accelerometer, and magnetometer, and outputs quaternion attitude;

[0044] Bottom contact detection module 530: includes foot pressure sensor 531 and ultrasonic ranging unit 532, used to detect whether there is contact with the bottom of the water or an obstacle;

[0045] Visual Sensor 540: RGB-D camera, used to build local environment maps;

[0046] Inertial Measurement Unit 550: Provides information on the body's angular velocity and linear acceleration;

[0047] The central control unit 600 adopts an embedded industrial computer with a real-time operating system, and is responsible for sensor data fusion, decision control and actuator driving.

[0048] Example 2: Control Method and Algorithm Implementation

[0049] 2.1 Environmental Perception and Pattern Decision Making (Refer to) Figure 4 )

[0050] The system runs with a control cycle of Ts=20ms, and performs the following steps in each cycle:

[0051] Step S1: Data Acquisition and Preprocessing

[0052] Data collection includes water depth h, attitude quaternion q, and foot pressure F. i (i=1, ...,6), distance d from the bottom of the ultrasonic wave b Visual point cloud P cloud .

[0053] Apply moving average filtering to the water depth data: The attitude is updated using complementary filtering to obtain the aircraft's pitch angle θ and roll angle ϕ.

[0054] Step S2: Environmental Status Assessment

[0055] Define environment state variables:

[0056] Land State S L ĥ <h th And at least 3 feet detected pressure F i >F min ;

[0057] Water state S W :ĥ≥h thFurthermore, the pressure detection was invalid;

[0058] Transition state S T : ĥ∈[h th -0.1, h th +0.1] and the pressure detection is unstable.

[0059] Where h th =0.2m, F min =10N.

[0060] Step S3: Pattern Decision Output

[0061] Mode switching is implemented using a finite state machine:

[0062] If the current value is S L And continue for t hold If the time is 2 seconds, switch to land walking mode;

[0063] If the current value is S W And continue for t hold Then switch to water propulsion mode;

[0064] If it is S T Then it enters the transitional adaptive mode, simultaneously enabling partial foot strokes and propeller micro-thrust.

[0065] 2.2 Adaptive Gait Generation

[0066] In the land walking mode, a gait generation algorithm based on CPG (Central Pattern Generator) is adopted:

[0067] Define a phase oscillator: Where f is the step frequency, w ij For coupling weights, ψ ij This represents the phase difference.

[0068] Gait parameters are adaptively adjusted based on terrain slope θ and roughness σ: Step height: In water propulsion mode, foot drive is turned off, and the target heading ψ is determined. target Calculate the propeller differential speed with the current yaw ψ: Left propeller speed n L =n0+Δn, right propeller speed n R =n0−Δn.

[0069] 2.3 Bottom-out protection strategy

[0070] When the water depth is ĥ <h safe =0.5m or ultrasonic detection of the bottom distance d b <d safe When the depth is 0.3m, the bottom-touching protection is triggered.

[0071] Increase the height of the drone: By adjusting the angle of the foot joints, the height of the drone relative to the seabed can be increased. ;

[0072] Adjust the propeller pitch angle: If the altitude adjustment has reached its upper limit but the water level is still close to the bottom, control the propeller pitch angle γ to deflect upwards: ;

[0073] Decelerate or hover: If the risk of bottoming out cannot be avoided, reduce propulsion power or enter a hovering state and report an alarm.

[0074] 2.4 Energy Optimization Strategy

[0075] Dynamic power allocation is achieved based on a deep reinforcement learning (DRL) model; the state space includes: current mode m∈{L, W, T}; water depth h; attitude angles θ, ϕ; and task load level L. task Remaining power E remain .

[0076] The motion space is a power allocation vector for each actuator:

[0077]

[0078] The reward function is designed as follows:

[0079]

[0080] Where w1=0.5, w2=10, and w3=20, they correspond to energy consumption, stall penalty, and collision penalty, respectively.

[0081] The training uses the PPO algorithm, with a network structure of 3 fully connected layers, each with 256 neurons. The output layer uses Softmax normalization. After training, the model is deployed in the central control unit, and a power redistribution decision is made every 10 seconds.

[0082] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0083] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0084] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0085] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0086] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A hexapod robot with amphibious capabilities, characterized in that, include: fuselage (100); Six walking legs (200) are symmetrically arranged on both sides of the fuselage (100), and each leg is equipped with a waterproof drive joint (210) at the end. The protective box (300) is located at the base of the walking foot (200) and has an integrated propeller inside for water propulsion; A multi-sensor system (500) includes a depth sensor (510), an attitude sensor (520), and a bottom-touching detection module (530). The central control unit (600) is used to collect sensor data in real time, determine whether the current environment is land or water, and automatically switch between walking mode and water propulsion mode.

2. A hexapod robot with amphibious capabilities according to claim 1, characterized in that: The protective box (300) is an openable and closable structure. It is closed in land mode to protect the propeller and opened in water mode to expose the propeller.

3. A hexapod robot with amphibious capabilities according to claim 1, characterized in that: The bottom contact detection module (530) includes a pressure sensor (531) and an ultrasonic ranging unit (532) located at the end of the walking foot (200) for detecting whether it is in contact with the bottom of the water or an obstacle.

4. A hexapod robot with amphibious capabilities according to claim 1, characterized in that: The central control unit (600) is also connected to a vision sensor (540) and an inertial measurement unit (550) for constructing a local environment map and real-time attitude estimation.

5. A hexapod robot with amphibious capabilities according to claim 1, characterized in that: The central control unit (600) adaptively adjusts the walking gait and propeller speed according to water depth and terrain information, and implements a bottom-touching protection strategy.

6. A hexapod robot with amphibious capabilities according to claim 5, characterized in that: The bottom-touching protection strategy includes: automatically raising the fuselage height or adjusting the propeller pitch angle when approaching the bottom of the water is detected.

7. A hexapod robot with amphibious capabilities according to claim 1, characterized in that: The central control unit (600) also executes an energy optimization strategy, dynamically allocating power to the joint motors and propellers according to the current mode and task load.

8. A hexapod robot with amphibious capabilities according to claim 7, characterized in that: The energy optimization strategy is based on a deep reinforcement learning model and aims to minimize total energy consumption, outputting the optimal power allocation ratio for each actuator.

9. A hexapod robot with amphibious capabilities according to claim 1, characterized in that: It also includes a communication module for receiving remote commands and uploading environmental data and system status.

10. A hexapod robot with amphibious capabilities according to claim 1, characterized in that: The walking foot (200) adopts a two-stage linkage structure, with sealing rings and drainage valves at the joints, providing underwater pressure resistance and self-drainage capabilities.

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