A robot small leg double finger wheel foot structure and a humanoid robot

Abstract

The application is specifically a robot small leg double finger wheel foot structure and humanoid robot, comprising: small leg and first and second motors on both sides of the upper part of the small leg. The first motor is close to the knee joint, and the axis thereof is parallel to the axis of the knee joint and is upwardly offset; the second motor is below the first motor and on the line between the first motor and the ankle joint. The axes of the two motors and the axis of the knee joint form an acute angle triangle in lateral projection. The first and second driving wheels are respectively fixed to the rotors of the two motors; the first and second driven wheels are connected with the inner rings of the ankle joint bearings, and the outer rings of the bearings are fixed to the ankle; the first and second toes are respectively connected with the driven wheels. The driving wheels and the driven wheels are connected through flexible transmission members to form two sets of independent driving systems, which are axially inserted and nested on both sides of the knee joint and the ankle joint and are asymmetrically distributed. The application has the advantages that: while ensuring high dynamic response control of the small leg, elastic buffer energy storage, complex terrain self-adaptive balance and wheel foot function expansion are realized.

Description

Technical Field

[0001] This invention relates to the field of humanoid robot technology, specifically to a robot's lower leg double-finger wheel foot structure and a humanoid robot. Background Technology

[0002] In the field of existing intelligent robot technology, especially in the design of the lower leg and foot structure of humanoid robots, common driving methods include using rotary motors with reducers and linkage mechanisms, or using a drive transmission structure composed of motors and planetary roller screws to control the pitch and lateral movements of the ankle joint, thereby achieving foot swing and support. However, these traditional structures have many shortcomings in practical applications. First, linkages or screw drives are rigid connections, lacking the elastic characteristics of fascia and ligaments in the human foot, making it difficult to effectively buffer the impact of ground reaction forces during walking, running, or jumping, resulting in stiff robot movements, high impact noise, and easy damage to the mechanical structure. Second, the effective range of motion of linkages and screw drives is limited, easily leading to dead points or jamming points, restricting the flexibility of foot posture adjustment. Furthermore, such rigid transmission systems cannot store and release energy, resulting in low efficiency in the conversion between kinetic and potential energy, poor energy utilization, and high overall energy consumption. In addition, in existing solutions, the motor, reducer and transmission components are usually located in the middle of the lower leg or even closer to the foot, resulting in a large inertia at the end of the leg and the center of gravity being far away from the knee joint. This reduces the dynamic response speed and control stability of the leg, which is not conducive to achieving high-speed, high-dynamic motion control.

[0003] Meanwhile, existing foot structures have poor scalability, making them incompatible with wheeled foot modules and unable to take advantage of the low-energy consumption and high-speed cruising capabilities of wheeled drives. Some hybrid wheel-foot solutions place the drive motor directly at the end of the wheel or foot, further increasing the end effector inertia. Furthermore, the motor's proximity to the ground necessitates high protection levels, resulting in poor reliability and susceptibility to damage in complex or harsh environments. Additionally, when the robot needs to perform delicate operations while stationary, pure wheeled feet cannot provide stable support.

[0004] Therefore, there is an urgent need for a new type of lower leg and foot structure that can take into account elastic cushioning, dynamic response, energy consumption optimization, and terrain adaptability. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a robot lower leg double-finger wheel foot structure and a humanoid robot, so as to achieve elastic buffer energy storage, adaptive balance in complex terrain and wheel foot function expansion while ensuring high dynamic response control of the lower leg.

[0006] To achieve the above objectives, a robot lower leg dual-finger wheel foot structure is designed, comprising: a robot lower leg structure, a first motor and a second motor respectively fixed to the upper two sides of the lower leg, the first motor being located on the upper part of the lower leg near the knee joint, and the second motor being located below the first motor; the axis of the first motor is parallel to the axis of the knee joint and is offset upward relative to the axis of the knee joint; the second motor is located on the connecting line determined by the first motor and the ankle joint at the lower part of the lower leg; the axes of the first motor and the second motor and the axis of the knee joint form a triangle relationship in the lateral projection, and all three angles of the triangle are acute angles; The first driving wheel and the second driving wheel are fixed to the rotors of the first motor and the second motor, respectively. The first driven wheel and the second driven wheel are connected to the inner rings of two bearings located at the ankle joint, and the outer rings of the two bearings are fixed to the ankle on both sides of the lower leg. The first toe is connected to the first driven wheel, and the second toe is connected to the second driven wheel. The first driving wheel and the first driven wheel, and the second driving wheel and the second driven wheel are connected by the first flexible transmission component and the second flexible transmission component, respectively, forming two independent drive systems. The two drive systems are axially interwoven and nested on both sides of the knee and ankle joints to form an asymmetrical distribution.

[0007] Preferably, the present invention further includes: the first flexible transmission component and the second flexible transmission component are synchronous belts or multi-wedge belts, which are made of high-elasticity rubber, or polyurethane, or a composite elastic tendon material composed of high-elasticity fibers, resin and reinforcing strips.

[0008] Preferably, the present invention further includes: a wheel, which is mounted and fixed on a driven wheel and replaces the corresponding toe, forming a composite wheel-foot mating structure with another toe.

[0009] Preferably, the present invention further includes: a controller, which is electrically connected to the first motor and the second motor respectively, and realizes synchronous cross-coupling control of the first motor and the second motor through encoder signals in the controller, thereby forming synchronous movement or independent drive control of the first toe and the second toe.

[0010] Preferably, the present invention further includes: the first motor and the second motor are controlled by a force-position hybrid control via a controller, wherein the controller is configured as an adaptive inference model trained by a reinforcement learning strategy to control the first toe and the second toe to perform balancing and cushioning actions on the ground.

[0011] Preferably, the present invention further includes: the tension vectors of the first flexible transmission member and the second flexible transmission member do not pass through the center of the ankle or knee joint, forming a restoring torque; when the ankle or knee joint is deflected by an external force, the restoring torque generates a force opposite to the direction of deflection, assisting the ankle or knee joint to return to center and enhancing dynamic balance.

[0012] Preferably, the present invention further includes: the first toe and the second toe forming a two-toed foot structure, and two sets of drive systems independently controlling the two toes to move separately with different forces and timings, adapting to automatic balance and gripping under complex terrain.

[0013] Preferably, the present invention further includes: the first motor and the second motor are standard geared motors with reducers, standard direct drive motors or torque servo motors.

[0014] Preferably, the present invention further includes: a tension wheel is provided inside the lower leg, the rolling surface of the tension wheel cooperates with the second flexible transmission member to apply a preload to the second flexible transmission member, forming a unilateral tension drive system, which, together with the drive system containing the first flexible transmission member, forms a dual drive system with asymmetric damping characteristics. Through the asymmetric damping characteristics, the vibration energy of the flexible transmission member is absorbed and dissipated, reducing the vibration of the drive system.

[0015] The present invention also provides a humanoid robot, including the aforementioned robot lower leg double-finger wheel foot structure.

[0016] Compared with the prior art, the advantages of this invention are: This invention fixes the first and second motors to the upper sides of the lower leg, respectively, and arranges two independent belt drive systems in an asymmetrical distribution, axially interlocking on both sides of the knee and ankle joints. The axes of the two motors and the knee joint axis form a triangle in lateral projection, with all three angles being acute. This asymmetrical arrangement ensures that the tension vectors of the first and second flexible drive components do not pass through the center of the ankle or knee joint, thus generating a restoring torque. When the joint is deflected by an external force, this restoring torque automatically generates a force opposite to the direction of deflection, assisting the joint in returning to center, significantly enhancing the joint's dynamic balance and anti-interference ability, and enabling the lower leg to remain stable during high-speed movement or external impact. This invention uses synchronous belts or multi-wedge belts made of highly elastic rubber, polyurethane, or composite elastic tendon materials as flexible drive components. Combined with the asymmetrical tension path, the transmission system possesses an elastic buffering function similar to biological fascia, effectively absorbing and releasing the impact of ground reaction forces during walking, running, or jumping, realizing the conversion and storage of kinetic and potential energy, reducing energy consumption, while also reducing rigid impact and motion noise, and avoiding mechanical damage. This invention divides the foot into independently driven first and second toes. Two drive systems can control each toe to move independently with different forces and timings, adapting to automatic balance and gripping in complex terrain, overcoming the technical bias of traditional one-piece soles' poor adaptability to uneven surfaces. Simultaneously, this invention can be expanded to include a wheel mounted on a driven wheel, replacing the corresponding toe, forming a composite wheel-foot structure. This retains the stability needed for precise bipedal operation while utilizing a wheel structure for low-energy, high-speed cruising, combining the advantages of both foot-based and wheel-based systems. The invention centrally positions the motor and drive wheel on the upper part of the lower leg near the knee joint, bringing the leg's center of gravity closer to the root, significantly reducing end-effector inertia, and improving the lower leg's dynamic response speed and control precision, facilitating high-speed, high-dynamic motion control. This invention features a simple structure, fully enclosed protection, no exposed moving parts, high reliability, adaptability to complex and harsh environments, and an aesthetically pleasing appearance with high safety. Attached Figure Description

[0017] Figure 1 This is a front sectional view of the present invention; Figure 2 This is a right-side sectional view of the present invention; Figure 3 This is a left sectional view of the present invention; Figure 4 This is a frontal sectional view of the invention, which replaces the second toe with a wheel; Figure 5 This is a right sectional view illustrating the positional relationship between the first motor, the second motor, the knee joint, and the ankle joint in this invention. In the diagram: 1. Lower leg, 2. First motor, 3. Second motor, 4. First driving wheel, 5. First driven wheel, 6. Second driving wheel, 7. Second driven wheel, 8. First flexible transmission component, 9. Second flexible transmission component, 10. First toe, 11. Second toe, 12. Bearing, 13. Wheel, 14. Knee joint, 15. Ankle joint, 16. Tension wheel. Detailed Implementation

[0018] To make the purpose, principle and structure of the present invention clearer, the following description is provided in conjunction with the accompanying drawings and specific embodiments.

[0019] like Figures 1 to 5 As shown, this invention provides a robot lower leg double-finger wheel foot structure and a humanoid robot using this structure. The structure includes a robot lower leg 1, which is a generally vertically extending shell structure with an internal cavity for accommodating transmission components. A knee joint 14 is located at the top, and an ankle joint 15 is located at the bottom. A first motor 2 and a second motor 3 are fixed to the upper sides of the lower leg 1, respectively. The first motor 2 is positioned on the upper part of the lower leg 1 near the knee joint 14, and the second motor 3 is positioned below the first motor 2. The axis of the first motor 2 is approximately parallel to the axis of the knee joint 14 in space. The rotation axes of both the first motor 2 and the knee joint 14 are laterally oriented, and the axis of the first motor 2 is offset upwards relative to the axis of the knee joint 14. That is, there is a certain distance in the vertical direction between the rotation center axis of the first motor 2 and the rotation center axis of the knee joint 14, and this distance is approximately the radius of the first motor 2. The second motor 3 is positioned on the line connecting the first motor 2 and the ankle joint 15 at the lower part of the lower leg 1. Specifically, the second motor 3 is arranged along the line connecting the first motor 2 and the ankle joint 15, extending along the lower leg 1. This structure allows the second motor 3 to be collinear with the first motor 2 and the ankle joint 15, creating an asymmetrical triangular force relationship in space. This optimizes the weight distribution of the lower leg 1 and reduces the end-effector inertia, contributing to the generation of restoring torque and enhancing the joint's dynamic balance. The axes of the first motor 2, the second motor 3, and the knee joint 14 form a triangle in lateral projection, with all three angles being acute. This asymmetrical arrangement creates a stable force structure in space for the two drive systems, further improving the joint's dynamic balance.

[0020] A first driving wheel 4 is fixed to the rotor of the first motor 2, and a second driving wheel 6 is fixed to the rotor of the second motor 3. Both the first driving wheel 4 and the second driving wheel 6 are synchronous pulleys or multi-ribbed pulleys, rotating synchronously with the rotors of the first motor 2 and the second motor 3, respectively. Specifically, the rotors of the first motor 2 and the second motor 3 form a rotating shaft, and the first driving wheel 4 and the second driving wheel 6 can be welded or bolted to the rotating shaft and move accordingly. Two bearings 12 are provided at the ankle joint 15 at the lower part of the lower leg 1. The outer rings of the two bearings 12 are fixed to the ankles on both sides of the lower leg 1, and the inner rings of the two bearings 12 are connected to a first driven wheel 5 and a second driven wheel 7, respectively. That is, the first driven wheel 5 is connected to the inner ring of one of the bearings 12, and the second driven wheel 7 is connected to the inner ring of the other bearing 12, so that while the first driven wheel 5 and the second driven wheel 7 are confined at the ankle joint 15 of the lower leg 1, they can rotate freely relative to the lower leg 1. A first toe 10 is connected to the first driven wheel 5, and a second toe 11 is connected to the second driven wheel 7. The first toe 10 and the second toe 11 constitute two independent toes in the two-toed foot structure. The first toe 10 and the second toe 11 oscillate around the first driven wheel 5 and the second driven wheel 7 as the first driven wheel 5 and the second driven wheel 7 reciprocate. The first driving wheel 4 and the first driven wheel 5 are connected by a first flexible transmission member 8, and the second driving wheel 6 and the second driven wheel 7 are connected by a second flexible transmission member 9, thus forming two independent drive systems. These two drive systems are axially interwoven and nested on both sides of the knee joint 14 and the ankle joint 15, forming an asymmetrical distribution. That is, the first flexible transmission member 8 and the second flexible transmission member 9 are not symmetrically parallel in space, but are arranged in an interwoven and staggered manner, so that the transmission path forms different angles and lever arm relationships on both sides of the joint.

[0021] In this embodiment, the first flexible transmission component 8 and the second flexible transmission component 9 are preferably synchronous belts or multi-wedge belts, made of high-elasticity rubber, polyurethane, or a composite elastic tendon material composed of high-elasticity fibers, resin, and reinforcing strips. This material selection enables the first flexible transmission component 8 and the second flexible transmission component 9 to possess elastic cushioning functions similar to biological fascia, effectively absorbing and releasing the impact of ground reaction forces during walking, running, or jumping, achieving the conversion and storage of kinetic and potential energy, reducing energy consumption, and simultaneously reducing rigid impacts and motion noise, thus avoiding mechanical damage.

[0022] To further improve the stability and dynamic response performance of the transmission system, a tension wheel 16 can be installed inside the lower leg 1. The rolling surface of the tension wheel 16 cooperates with the second flexible transmission component 9, applying a preload to the second flexible transmission component 9 to form a unilaterally tensioned drive system. This unilaterally tensioned drive system works in conjunction with the drive system containing the first flexible transmission component 8 to form a dual drive system with asymmetric damping characteristics. Through this asymmetric damping characteristic, the vibration energy generated by the first flexible transmission component 8 and the second flexible transmission component 9 during high-speed movement can be effectively absorbed and dissipated, reducing drive system vibration and improving transmission smoothness and control accuracy. The specific installation position of the tension wheel 16 can be adjusted according to the orientation and tensioning requirements of the second flexible transmission component 9, and it is usually set inside the lower leg 1 near the middle of the second flexible transmission component 9.

[0023] The drive system containing the first motor 2 transmits power from above the knee joint 14 to the ankle joint 15 via the first flexible transmission component 8. Its relatively long transmission path covers the entire lower leg from the knee joint 14 to the ankle joint 15, simulating the mechanical characteristics of human leg muscles. This provides the robot with a high elastic margin, enabling rapid joint movement and ground impact cushioning. The drive system containing the second motor 3 is located below the first motor 2, between the ankle joint 15 and the knee joint 14. It applies preload to the second flexible transmission component 9 via the tension wheel 16, simulating the function of the human Achilles tendon. Its relatively short transmission path and high stiffness are specifically designed to compensate for the slower dynamic response caused by the longer path of the drive system containing the first motor 2. The two systems form a complementary composite transmission structure with long and short paths, significantly improving the response speed and control accuracy of the entire lower leg drive system while ensuring elastic cushioning capabilities.

[0024] This invention also provides a wheel extension structure. For example... Figure 4 As shown, a wheel 13 can be mounted and fixed to either the first driven wheel 5 or the second driven wheel 7, replacing the corresponding toe. For example, wheel 13 can be fixed to the second driven wheel 7, replacing the second toe 11. The wheel 13 and the retained first toe 10 form a composite wheel-foot mating structure. In this configuration, when the robot needs to cruise at high speed on flat ground, wheel 13 can undertake the main rolling support function, achieving efficient movement with low energy consumption. When the robot needs to perform delicate operations while stationary or traverse complex terrain, the first toe 10 can serve as a stable supporting toe, providing reliable ground support. This composite wheel-foot mating structure combines the advantages of both wheel and foot structures, retaining the stability of performing delicate operations while utilizing the wheel structure to achieve low energy consumption and high-speed cruising, significantly improving the robot's terrain adaptability and task flexibility.

[0025] The invention also includes a controller (not shown in the figure), which is electrically connected to the first motor 2 and the second motor 3. The controller integrates an encoder signal acquisition module, which uses encoder signals to achieve synchronous cross-coupling control of the first motor 2 and the second motor 3. Synchronous cross-coupling control refers to the controller acquiring real-time speed, position, and torque information of the first motor 2 and the second motor 3, and coordinating the motion state of the two motors according to a preset motion relationship model, enabling the first toe 10 and the second toe 11 to achieve synchronous movement or independent drive control. When walking on flat ground or running at high speed, the controller uses precise transmission ratio control to make the first toe 10 and the second toe 11 move synchronously, maintaining a stable gait. When adapting to complex terrain, the controller can independently control the first toe 10 and the second toe 11 to move separately with different forces and timings, achieving automatic balance and grip. Specific motion relationship models, control schemes, transmission ratios, etc., can be set by those skilled in the art according to their needs.

[0026] More preferably, the first motor 2 and the second motor 3 employ a force-position hybrid control strategy via a controller. The controller is equipped with an adaptive inference model trained using reinforcement learning. This model can infer the optimal control commands in real time based on the robot's current motion state, terrain information, and foot force conditions, controlling the first toe 10 and the second toe 11 to perform balancing and cushioning movements on the ground. The reinforcement learning strategy can be trained on the ground or in a simulation environment, and through extensive iterative training, the model learns the optimal control strategy for different terrains and working conditions.

[0027] In this invention, the tension vectors of the first flexible transmission member 8 and the second flexible transmission member 9 do not pass through the center of the ankle joint 15 or the knee joint 14. Specifically, because the axis of the first motor 2 is offset upward relative to the axis of the knee joint 14, and the axes of the first motor 2 and the second motor 3 form an acute triangle with the axis of the knee joint 14 in the lateral projection, the tension directions of the first flexible transmission member 8 and the second flexible transmission member 9 on both sides of the joint do not point towards the center of the joint, but are offset from the center of the joint by a certain distance. This offset will generate a restoring torque, that is, when the ankle joint 15 or the knee joint 14 is deflected by an external force, the tension in the first flexible transmission member 8 and the second flexible transmission member 9 will generate a torque opposite to the direction of deflection. The direction of this torque is opposite to the direction of deflection, and its magnitude is related to the deflection angle and the magnitude of the tension. This restoring torque can automatically help the ankle joint 15 or the knee joint 14 return to center, significantly enhancing the dynamic balance and anti-interference ability of the joint. Compared with traditional linkage or lead screw transmissions, the tension vector of flexible transmission components always maintains a relatively stable lever arm within the joint's range of motion. This avoids the problems of excessive lever arm changes or dead points in linkage transmissions, thus enabling the joint to achieve good dynamic balance control in various postures.

[0028] The first toe 10 and the second toe 11 form a two-toed foot structure. Two drive systems independently control the two toes to move separately with different forces and timings, adapting to automatic balance and gripping in complex terrain. For example, when the robot walks on sloping or gravelly ground, the first toe 10 and the second toe 11 can contact the ground at different angles and forces, mimicking the foot movement of bipedal animals such as ostriches, actively adapting to terrain changes and improving grip and stability. On flat ground, the two toes can achieve uniform force through synchronous control, maintaining a stable walking posture. This two-toed foot structure overcomes the technical bias of traditional one-piece footplates having poor adaptability to uneven ground, significantly improving the robot's terrain adaptability.

[0029] The first motor 2 and the second motor 3 in this invention can be a standard geared motor with a reducer, a standard direct-drive motor, or a torque servo motor. Regardless of the type of motor used, it should meet the requirements of high dynamic response, high-precision control, and sufficient output torque. In practical applications, the appropriate motor type can be selected based on the robot's load capacity, movement speed, and control accuracy requirements.

[0030] The present invention also provides a humanoid robot, which includes the aforementioned two-toed wheel-like foot structure for the robot's lower legs. Specifically, each of the humanoid robot's left and right legs is equipped with one of the aforementioned structures, and the two legs are coordinated and controlled by a controller. When walking, running, jumping, or standing still, the humanoid robot can utilize the advantages of the aforementioned structure, such as elastic cushioning, dynamic balance, and wheel-like foot extension.

[0031] The assembly relationship and working principle of the present invention will be further explained below with reference to the accompanying drawings. Figure 1 As shown, within the upper cavity of the lower leg 1, a first motor 2 is fixed to the right side wall, its rotor axis extending horizontally, and a first driving wheel 4 is fixed to this rotor. A second motor 3 is fixed to the left side wall below the first motor 2, its rotor axis also extending horizontally, and a second driving wheel 6 is fixed to this rotor. A first flexible transmission element 8 is tensioned and wound between the first driving wheel 4 and the first driven wheel 5, and a second flexible transmission element 9 is tensioned and wound between the second driving wheel 6 and the second driven wheel 7. The first driven wheel 5 and the second driven wheel 7 are respectively mounted on both sides of the ankle joint 15 at the lower part of the lower leg 1 via bearings 12. A first toe 10 is fixed to the first driven wheel 5 and extends downward, and a second toe 11 is fixed to the second driven wheel 7 and extends downward. Figure 2 and Figure 3 As shown, from the right and left viewpoints, it can be seen that the first flexible transmission component 8 and the second flexible transmission component 9 are arranged in an interlocking and nested manner on both sides of the knee joint 14 and the ankle joint 15, forming an asymmetrical transmission path. Figure 5As shown, the axes of the first motor 2, the second motor 3, and the knee joint 14 form an acute triangle relationship in the lateral projection. This structural feature enables the two drive systems to form a stable mechanical structure in space.

[0032] When the robot moves, the controller sends drive signals to the first motor 2 and the second motor 3 according to the preset motion mode or the output instructions of the adaptive inference model. The first motor 2 and the second motor 3 drive the first drive wheel 4 and the second drive wheel 6 to rotate, respectively. The power is transmitted to the first driven wheel 5 and the second driven wheel 7 through the first flexible transmission member 8 and the second flexible transmission member 9, which in turn drives the first toe 10 and the second toe 11 to rotate relative to the ankle joint 15. During walking, when the first toe 10 or the second toe 11 contacts the ground and is impacted by the ground reaction force, the impact force is partially absorbed and stored by the elastic deformation of the first flexible transmission member 8 and the second flexible transmission member 9. At the same time, the asymmetrically arranged tension vector generates a restoring torque, which helps the ankle joint 15 and the knee joint 14 to remain stable. When the robot needs to cruise at high speed, the wheel 13 can replace the second toe 11. The wheel 13 rolls in contact with the ground, and the first toe 10 serves as an auxiliary support or a backup support, realizing a composite function of wheeled movement and foot support.

[0033] In summary, the robot's lower leg double-fingered wheel foot structure and humanoid robot provided by this invention, by fixing the first and second motors to the upper sides of the lower leg respectively, and by having two independent belt drive systems axially interlocked and nested on both sides of the knee and ankle joints to form an asymmetrical distribution, with the axes of the two motors and the knee joint axis forming an acute-angled triangle relationship in the lateral projection, ensures that the tension vector of the flexible transmission component does not pass through the joint center, forming a restoring torque and enhancing the joint's dynamic balance and anti-interference ability. Simultaneously, the flexible transmission component, made of highly elastic material, achieves elastic buffering and energy storage and release. The double-fingered foot structure and expandable wheel structure enable the robot to adapt to complex terrain and achieve low-energy, high-speed cruising. This structure is simple, fully enclosed, and has low end-effector inertia, offering advantages such as high dynamic response, high reliability, and high safety, making it suitable for various humanoid robots, exoskeleton robots, and biomimetic robots.

[0034] The above description is merely a specific embodiment of the invention, but the scope of protection of the invention is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the invention, based on the technical solution and concept of the invention, should be covered within the scope of protection of the invention.

Claims

1. A robot lower leg double-finger wheel foot structure, characterized in that, include: The robot's lower leg structure has a first motor and a second motor fixed to the upper sides of the lower leg, respectively. The first motor is located on the upper part of the lower leg near the knee joint, and the second motor is located below the first motor. The axis of the first motor is parallel to the axis of the knee joint and is offset upward relative to the axis of the knee joint. The second motor is positioned on the connecting line defined by the first motor and the ankle joint at the lower part of the lower leg; The axes of the first and second motors and the axis of the knee joint form a triangle on the lateral projection, and all three angles of the triangle are acute angles. The first driving wheel and the second driving wheel are fixed on the rotor of the first motor and the rotor of the second motor, respectively; The first driven wheel and the second driven wheel are respectively connected to the inner rings of two bearings located at the ankle joint, and the outer rings of the two bearings are fixed to the ankle on both sides of the lower leg. The first toe is connected to the first driven wheel, and the second toe is connected to the second driven wheel; The first driving wheel and the first driven wheel, and the second driving wheel and the second driven wheel are respectively connected by the first flexible transmission component and the second flexible transmission component, forming two independent drive systems. The two drive systems are axially interwoven and nested on both sides of the knee joint and ankle joint to form an asymmetrical distribution, so that the tension vector of the first flexible transmission component and the second flexible transmission component does not pass through the joint center, thus forming a restoring torque. The lower leg is also equipped with a tension wheel. The rolling surface of the tension wheel cooperates with the second flexible transmission component to apply a preload to the second flexible transmission component, forming a unilateral tension drive system. Together with the drive system containing the first flexible transmission component, it forms a dual drive system with asymmetric damping characteristics. Through the asymmetric damping characteristics, it absorbs and dissipates the vibration energy of the flexible transmission component, reducing the vibration of the drive system.

2. The robot lower leg double-finger wheel foot structure as described in claim 1, characterized in that, The first and second flexible transmission components are synchronous belts or multi-wedge belts, made of high-elasticity rubber, polyurethane, or a composite elastic tendon material composed of high-elasticity fibers, resin, and reinforcing belts.

3. The robot lower leg double-finger wheel foot structure as described in claim 1, characterized in that, It also includes wheels, which are mounted and fixed on a driven wheel and replace the corresponding toe, forming a compound wheel-foot mating structure with the other toe.

4. The robot lower leg double-finger wheel foot structure as described in claim 1, characterized in that, It also includes a controller, which is electrically connected to the first motor and the second motor respectively. The controller realizes synchronous cross-coupling control of the first motor and the second motor through the encoder signal in the controller, so as to form synchronous movement or independent drive control of the first motor and the second motor.

5. The robot lower leg double-finger wheel foot structure as described in claim 4, characterized in that, The first and second motors are controlled by a force-position hybrid control system via a controller configured as an adaptive inference model trained by a reinforcement learning strategy, which controls the first and second toes to perform balancing and cushioning actions on the ground.

6. The robot lower leg double-finger wheel foot structure as described in claim 1, characterized in that, The tension vectors of the first and second flexible transmission components do not pass through the center of the ankle or knee joint, thus forming a restoring torque. When the ankle or knee joint is deflected by an external force, the restoring torque generates a force opposite to the direction of deflection, assisting the ankle or knee joint to return to center and enhancing dynamic balance.

7. The robot lower leg double-finger wheel foot structure as described in claim 1, characterized in that, The first and second toes form a two-toed foot structure. Two drive systems independently control the two toes to move separately with different forces and timings, adapting to automatic balance and gripping in complex terrain.

8. The robot lower leg double-finger wheel foot structure as described in claim 1, characterized in that, The first and second motors are standard geared motors with reducers, standard direct drive motors, or torque servo motors.

9. A humanoid robot, characterized in that, Includes the robot's lower leg double-finger wheel foot structure as described in any one of claims 1 to 8.

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