A wheelchair robot chassis and a wheelchair robot

Abstract

The application relates to the technical field of mobile robot chassis, and discloses a wheelchair robot chassis and a wheelchair robot, wherein the wheelchair robot comprises a vehicle body bearing frame, four driving wheel groups, four independent suspension mechanisms connected between the driving wheel groups and the vehicle body bearing frame, and four driving wheel groups symmetrically arranged, wherein each driving wheel group is installed at an angle relative to the front-rear middle axis of the vehicle body bearing frame, and the angle ranges from 1 DEG to 44 DEG. The application can solve the problem of insufficient trans-slot capability of the existing chassis, improve the forward propulsion efficiency, and simultaneously consider the omnidirectional translation and rotation capability.

Description

Technical Field

[0001] This invention relates to the field of mobile robot chassis technology. Specifically, it relates to a wheelchair robot chassis and a wheelchair robot. Background Technology

[0002] In current indoor and semi-outdoor robot applications, omnidirectional mobility is a core indicator for measuring chassis maneuverability. To achieve translational movement without changing the vehicle's orientation, existing technologies often employ omni-wheels or mecanum wheels with rollers.

[0003] In a conventional four-wheel layout, to balance the longitudinal (X-direction) and lateral (Y-direction) power output, designers typically arrange the four wheel sets at approximately a 45° angle relative to the vehicle's front and rear centerlines, a so-called "X-shaped" layout. With this layout, the combined force output efficiency of the four wheels is essentially equal when the chassis is moving forward and backward and laterally.

[0004] However, this traditional 45° balanced design faces significant challenges in the complex environments of real homes and cities. Most homes in China and globally contain small obstacles between 3cm and 5cm in height, such as wooden thresholds, sliding door tracks, bathroom height differences, and kitchen partition tracks. For chassis with a 45° cross-arrangement, when attempting to cross these thresholds parallel to the direction of travel, the effective orthogonal thrust component at wheel-obstacle contact is greatly weakened due to the large angle between the wheel roller axis and the threshold edge. This often leads to lateral slippage of the wheel assembly or rollers getting stuck in the track grooves, resulting in threshold crossing failure.

[0005] For wheelchair-carrying modes, failing to clear obstacles not only means being unable to enter or exit a room, but also may cause discomfort or even safety risks to the occupants due to severe impact or lateral slippage. Therefore, there is an urgent need for a wheelchair robot chassis that can maintain omnidirectional mobility while significantly improving vertical propulsion efficiency and obstacle-crossing capabilities. Summary of the Invention

[0006] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0007] This disclosure provides a wheelchair robot chassis that aims to solve the problem of insufficient threshold crossing ability of existing 45° arranged chassis, improve forward propulsion efficiency, and at the same time take into account omnidirectional translation and rotation capabilities.

[0008] In some embodiments, a wheelchair robot chassis is provided, comprising: Vehicle body load-bearing frame; Four drive wheel sets; Four independent suspension mechanisms are respectively connected between the drive wheel assembly and the vehicle body support frame; The four drive wheel sets are symmetrically arranged, each drive wheel set being at an angle relative to the front and rear centerlines of the vehicle body support frame. The device is installed at an angle ranging from 1° to 44°.

[0009] Preferably, the angle The range is 10° to 30°.

[0010] Preferably, the angle It is 20°.

[0011] Preferably, the independent suspension mechanism includes: a swing arm assembly hinged to the vehicle body support frame, a mounting bracket connected between the swing arm assembly and the drive wheel assembly, and a spring shock absorber connected between the swing arm assembly and the vehicle body support frame.

[0012] Preferably, the spring shock absorber integrates a damper.

[0013] Preferably, it also includes a motion control unit, which is configured to distribute the speed of the four drive wheel sets according to motion commands, and support forward linear movement, backward linear movement, lateral movement, diagonal movement and rotation in place.

[0014] Preferably, the motion control unit sets the output weight of the forward linear velocity component to be higher than the output weight of the lateral velocity component; Alternatively, the motion control unit may set the maximum speed threshold for the forward linear velocity component to be higher than the maximum speed threshold for the lateral velocity component.

[0015] Preferably, the diameter of the drive wheel assembly is 8 inches, 10 inches, or 12 inches.

[0016] Preferably, it also includes an attitude detection sensor, and the motion control unit triggers an obstacle-crossing mode when a threshold obstacle is detected based on the sensor data.

[0017] In some embodiments, a wheelchair robot is provided, including the wheelchair robot chassis described in any of the preceding embodiments.

[0018] This disclosure provides a wheelchair robot chassis that achieves the following technical effects: by reducing the installation angle of the drive wheel assembly from the traditional 45° to a range of 1° to 44°, it aims to redistribute the power vector. The core logic is to transform the previously redundant lateral force into a more powerful longitudinal propulsion force. Reducing the angle θ significantly increases the longitudinal traction component. When facing obstacles such as thresholds, the greater forward impulse can more effectively overcome vertical resistance, reduce wheel slippage, and improve forward propulsion efficiency and range. Although the angle deviates from the equidistant point, the symmetrical arrangement still ensures omnidirectional kinematic freedom. Through the synthesis of four-wheel velocity vectors, precise lateral translation and zero-radius rotation in place can still be achieved. Combined with an independent suspension mechanism, this arrangement ensures uniform grip on each wheel in complex terrain. This "strong longitudinal, stable lateral" strategy balances the power requirements of the wheelchair robot when traversing obstacles in a straight line with the need for agile obstacle avoidance in indoor environments.

[0019] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0020] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein: Figure 1 This is a schematic diagram of the overall structure of a wheelchair robot chassis as shown in the embodiments of this specification; Figure 2 This is a front view of a wheelchair robot chassis as shown in an embodiment of this specification; Figure 3 This is a partial structural diagram of a wheelchair robot chassis shown in an embodiment of this specification; Figure 4 This is a side view of a wheelchair robot chassis as shown in an embodiment of this specification.

[0021] Explanation of reference numerals in the attached figures: 1. Vehicle body load-bearing frame; 2. Drive wheel assembly; 3. Independent suspension mechanism; 31. Swing arm assembly; 32. Mounting bracket; 33. Spring shock absorber. Detailed Implementation

[0022] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0023] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate to implement embodiments of the present disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0024] Unless otherwise stated, the term "multiple" means two or more.

[0025] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0026] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0027] The term "correspondence" can refer to an association or binding relationship. The correspondence between A and B means that there is an association or binding relationship between A and B.

[0028] Reference Figure 1 A wheelchair robot chassis, comprising: Vehicle body load-bearing frame 1; Four drive wheel sets 2; Four independent suspension mechanisms 3 are respectively connected between the drive wheel set 2 and the vehicle body support frame 1; The four drive wheel sets 2 are symmetrically arranged, and each drive wheel set 2 is at an angle relative to the front and rear centerlines of the vehicle body support frame 1. Inclined installation, the angle The range is from 1° to 44°.

[0029] Each drive wheel set includes one omnidirectional wheel. However, in this embodiment, in addition to the omnidirectional wheel, it can also be any one of a Mecanum wheel, a differential drive standard wheel, or an active steering omnidirectional wheel. The four drive wheel sets 2 are symmetrically arranged as follows: with the vehicle's transverse centerline as the boundary, the two front omnidirectional wheels and the two rear omnidirectional wheels are symmetrically distributed. With the vehicle's front and rear centerlines (forward direction) as the boundary, the two left omnidirectional wheels and the two right omnidirectional wheels are symmetrically distributed.

[0030] The rotation axis of each drive wheel set 2 forms an angle with its corresponding mounting reference plane. From a top view, the angle between the rolling direction of the drive wheel set 2 and the front and rear center axes is the angle. .

[0031] Traditional chassis usually The angle is set to 45° to ensure that the longitudinal (X-direction) and lateral (Y-direction) power output components are completely equal.

[0032] The advantage of 1° to 44° in this application lies in reducing This makes the rolling plane of the wheelset more parallel to the front and rear center axes of the vehicle. When the force decreases, the effective force component of forward propulsion As it increases, It provides the total power for all-directional wheels.

[0033] In one embodiment of this application, the angle The range is 10° to 30°.

[0034] The optimal range is 10° to 30°: Experiments show that when the angle is less than 10°, the lateral translation efficiency of the chassis will be excessively reduced, resulting in impaired obstacle avoidance flexibility; while when the angle exceeds 30°, the shaking will increase significantly when crossing a threshold of more than 3cm.

[0035] In another embodiment of this application, the angle 20° Where 20° is the golden ratio point: At 20°, the chassis reaches its performance "sweet spot." At this angle, the effective force component for forward propulsion is approximately 2.75 times that for lateral propulsion (cot 20° ≈ 2.747). This ratio ensures that when facing common 5cm high floor rails or door sills in home environments, the upward climbing force generated at the contact point between the omnidirectional wheels and the edge of the obstacle is sufficient to overcome resistance, without causing lateral slippage as seen in a 45° layout.

[0036] Reference Figure 2 and Figure 3In one embodiment of this application specification, the independent suspension mechanism 3 includes: a swing arm assembly 31 hinged to the vehicle body support frame, a mounting bracket 32 ​​connected between the swing arm assembly 31 and the drive wheel set 2, and a spring shock absorber 33 connected between the swing arm assembly 31 and the vehicle body support frame 1.

[0037] One end of the swing arm assembly 31 is hinged to the vehicle body support frame 1 via a pin, which is the center of rotation of the entire independent suspension mechanism 3. A mounting bracket 32 ​​is fixedly connected to the middle section or the other end of the swing arm assembly 31. The mounting bracket 32 ​​is connected to the drive wheel set 2, which may be connected to the axle of the omnidirectional wheel. When the omnidirectional wheel encounters a sill and bounces upwards, it will cause the swing arm assembly to rotate around the pivot point. One end of the spring shock absorber is connected to a preset position on the swing arm assembly (usually the end away from the pin or on a preset lug), and the other end is connected obliquely or vertically upwards to the vehicle body support frame.

[0038] The spring damper 33 has an integrated damper inside.

[0039] When the drive wheel set 2 descends and lands after crossing the threshold, the damper can quickly dissipate the spring's rebound energy, preventing the wheelchair from swaying repeatedly. This plays a decisive role in improving the riding comfort of elderly passengers or ensuring the positioning accuracy of the robotic arm on top of the robot.

[0040] Reference Figure 4 In the embodiments described in this application specification, the diameter of the drive wheel set 2 is 8 inches, 10 inches, or 12 inches.

[0041] To adapt to different application scenarios, this application provides three typical wheel diameter configurations: 8-inch wheels (approximately 200mm): Suitable for extremely flat indoor environments (such as nursing homes and hospitals), focusing on low center of gravity and extreme turning radius.

[0042] 10-inch wheels (approximately 250mm): With a 20° angle and independent suspension mechanism, this configuration can perfectly cross the 3cm-4cm balcony threshold commonly found in standard residences.

[0043] 12-inch wheels (approximately 300mm): Suitable for semi-outdoor scenarios (such as community patrols or courtyards with steps), providing enhanced physical mobility.

[0044] In one embodiment of this application specification, a motion control unit is also included, which is configured to distribute the speed of the four drive wheel sets 32 according to motion commands, and support forward linear movement, backward linear movement, lateral movement, diagonal movement and rotation in place.

[0045] First, the motion control unit establishes a coordinate system: : The expected linear speed of movement forward and backward (forward is positive).

[0046] : Expected lateral translation velocity (positive on the left).

[0047] ω: The desired angular velocity of rotation in place (positive for counterclockwise).

[0048] L and W: The longitudinal and lateral distances from the chassis geometric center to the omnidirectional wheel axle.

[0049] : The angle of the drive wheel assembly relative to the central axis (a core parameter of this application, such as 20°).

[0050] For the four drive wheel sets 32 (front left M1, front right M2, rear left M3, rear right M4), the control unit distributes the rotational speed according to the following generalized formula: The sign of the formula depends on the specific wheel layout direction (pigeon-toed or splayed).

[0051] Allocation logic for different motion modes Move forward in a straight line or move backward in a straight line The parameter is set as follows: given ,set up = 0, ω= 0.

[0052] Result: The four drive wheel sets 32 all moved at the same speed. Rotate.

[0053] because Smaller (e.g., 20°) The value is very large (about 0.94), and almost all of the torque output by the motor is converted into forward thrust, thus achieving a powerful hurdle crossing.

[0054] lateral translation The parameter is set as follows: given ,set up = 0, ω= 0.

[0055] Result: The diagonal drive wheel set 32 ​​rotates in opposite directions (e.g., M1 and M2 turn in opposite directions).

[0056] At this moment, the omnidirectional wheel slips laterally, and the resultant force points to the side. Because... It is relatively small and moves slowly, but this meets the needs of precise indoor positioning.

[0057] Spinning in place The parameter is set as follows: given ω, set... = 0, = 0.

[0058] Result: The left drive wheel set 32 ​​(M1, M3) and the right drive wheel set 32 ​​(M2, M4) form a differential counter-drive.

[0059] The chassis rotates around its geometric center without producing any displacement.

[0060] diagonal movement The parameter is set as follows: (Given simultaneously) and The control unit calculates the distinct speed components of each of the four drive wheel sets through vector synthesis, enabling the chassis to move smoothly along any diagonal direction.

[0061] In one embodiment of this application specification, the motion control unit assigns an output weight or maximum speed threshold to the velocity component of forward linear movement, which is higher than the output weight or speed weight assigned to the velocity component of lateral movement. Alternatively, set a maximum speed threshold for the forward linear velocity component that is higher than the maximum speed threshold for the lateral velocity component.

[0062] Specifically, weighting coefficients Kx (vertical weight) and Ky (lateral weight) are introduced. The vertical weight is greater than the lateral weight; for example, Kx = 1.0 and Ky = 0.5 (or lower). When the user pushes the joystick to the far left (lateral movement) and the far front (forward linear movement), although the physical displacement of the joystick is the same, the forward speed component of the instruction sent by the motion control unit to the motor will be significantly higher than the lateral speed component. This weighting ensures that when the total current of the wheelchair robot is limited (to prevent overload), priority is given to ensuring the power supply to the forward motor, thus providing sufficient torque for a "powerful push" when encountering threshold obstacles.

[0063] Alternatively, by setting two independent saturation limiters, even if the motor is capable of rotating faster, or the control algorithm calculates a high speed, the limiters will force it to stay within the threshold. For example, the forward maximum speed threshold = 1.2 m / s, the lateral maximum speed threshold = 0.4 m / s, due to the omnidirectional wheel's angle... With a 20° layout, lateral translation relies entirely on the lateral sliding of the omnidirectional wheels. High-speed lateral translation can lead to severe vibration and wear. Setting a low threshold can protect the mechanical structure and ensure the accuracy of indoor positioning.

[0064] In the embodiments described in this specification, an attitude detection sensor is also included, and the motion control unit triggers an obstacle-crossing mode when a threshold obstacle is detected based on the sensor data.

[0065] The chassis integrates attitude detection sensors (typically including 6-axis or 9-axis IMUs, as well as encoders mounted on the wheel axles).

[0066] A threshold obstacle is identified when the sensor detects one of the following features: A sudden change in pitch angle indicates that the front wheels have been lifted.

[0067] Sudden change in motor current feedback: This indicates that the omnidirectional wheel is experiencing resistance, causing a surge in torque.

[0068] If the encoder speed decreases but the control signal does not decrease, it indicates that the omnidirectional wheel is slipping or jamming.

[0069] Once obstacle-crossing mode is triggered, the motion control unit performs the following closed-loop operation: Instantaneous current boost: Allows for exceeding the rated current limit for a short period of time (e.g., 500ms), providing 1.5 times the instantaneous peak torque.

[0070] Suspension compensation strategy: By adjusting the speed of the four drive wheel sets at the microsecond level, the elastic potential energy of the swing arm assembly is used to "swing" over the edge of the obstacle.

[0071] This embodiment aims to redistribute the power vector by reducing the installation angle of the drive wheel assembly from the traditional 45° to a range of 1° to 44°. The core logic is to transform the previously redundant lateral force into a more powerful longitudinal propulsion force. Reducing the angle θ significantly increases the longitudinal traction component. When facing obstacles such as thresholds, the greater forward impulse can more effectively overcome vertical resistance, reduce wheel slippage, and improve forward propulsion efficiency and range. Although the angle deviates from the equidistant point, the symmetrical arrangement still ensures omnidirectional kinematic freedom. Through the synthesis of four-wheel velocity vectors, precise lateral translation and zero-radius rotation in place can still be achieved. Combined with an independent suspension mechanism, this arrangement ensures uniform grip on each wheel in complex terrain. This "strong longitudinal, stable lateral" strategy balances the power requirements of the wheelchair robot when traversing obstacles in a straight line with the need for agile obstacle avoidance in indoor environments.

[0072] This specification also includes an embodiment of a wheelchair robot, which includes any of the wheelchair robot chassis described above.

[0073] The foregoing description and accompanying drawings fully illustrate embodiments of this disclosure to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, procedural, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terminology used in this application is for describing embodiments only and is not intended to limit the claims. As used in the description of embodiments and claims, the singular forms “a,” “an,” and “the” are intended to equally include the plural forms unless the context clearly indicates otherwise. Similarly, the term “and / or” as used in this application means including one or more of the associated listed items and all possible combinations thereof. Additionally, when used in this application, the term "comprise" and its variations "comprises" and / or "comprising" refer to the presence of stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. Without further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the process, method, or apparatus that includes said element. In this document, each embodiment may focus on the differences from other embodiments, and similar or identical parts between embodiments can be referred to mutually. For methods, products, etc., disclosed in the embodiments, if they correspond to the method section disclosed in the embodiments, the relevant parts can be referred to the description of the method section.

[0074] 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 the embodiments of this disclosure. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0075] The methods and products disclosed in the embodiments herein (including but not limited to devices, equipment, etc.) can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units may be merely 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. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be through some interfaces, and the indirect coupling or communication connection of devices or units may be electrical, mechanical, or other forms. 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 implement this embodiment according to actual needs. In addition, the functional units in the embodiments of this disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

Claims

1. A wheelchair robot chassis, characterized in that, include: Vehicle body load-bearing frame; Four drive wheel sets; Four independent suspension mechanisms are respectively connected between the drive wheel assembly and the vehicle body support frame; The four drive wheel sets are symmetrically arranged, each drive wheel set being at an angle relative to the front and rear centerlines of the vehicle body support frame. Inclined installation, the angle The range is from 1° to 44°.

2. The wheelchair robot chassis according to claim 1, characterized in that, The angle The range is 10° to 30°.

3. The wheelchair robot chassis according to claim 1, characterized in that, The angle It is 20°.

4. The wheelchair robot chassis according to claim 1, characterized in that, The independent suspension mechanism includes: a swing arm assembly hinged to the vehicle body support frame, a mounting bracket connected between the swing arm assembly and the drive wheel assembly, and a connection between the swing arm assembly and the vehicle body support frame.

5. A wheelchair robot chassis according to claim 4, characterized in that, The spring shock absorber integrates a damper.

6. The wheelchair robot chassis according to claim 1, characterized in that, It also includes a motion control unit, which is configured to distribute the speed of the four drive wheel sets according to motion commands, and support forward linear movement, backward linear movement, lateral movement, diagonal movement and rotation in place.

7. A wheelchair robot chassis according to claim 6, characterized in that, The motion control unit sets the output weight of the forward linear velocity component to be higher than the output weight of the lateral velocity component. Alternatively, the motion control unit may set the maximum speed threshold for the forward linear velocity component to be higher than the maximum speed threshold for the lateral velocity component.

8. A wheelchair robot chassis according to claim 1, characterized in that, The drive wheel assembly has a wheel diameter of 8 inches, 10 inches, or 12 inches.

9. A wheelchair robot chassis according to claim 6, characterized in that, It also includes an attitude detection sensor, and the motion control unit triggers an obstacle-crossing mode when a threshold obstacle is detected based on the sensor data.

10. A wheelchair robot, characterized in that, The chassis of the wheelchair robot includes any one of claims 1-9 above.

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