A damped adjustable robotic leg system and its control method

Abstract

This invention discloses a damped adjustable robot leg system and its control method. The leg system includes a thigh, a lower leg, a link, an adjustable damper, wheel feet, and a wheel-side motor. One end of the thigh is hinged to one end of the lower leg, while the lower leg is hinged to the other end of the thigh via a link, forming a parallelogram mechanism. The wheel feet are located at the other end of the lower leg, and the wheel-side motor is fixed to the side of the wheel feet to drive their movement. The adjustable damper is fixed between the wheel-side motor and the other end of the lower leg. The adjustable damper can adjust the damping of the leg system. When the adjustable damper is locked, the leg system is in a fully rigid state. This invention not only increases the robot's obstacle-crossing ability when walking on wheels, but also reduces the vibration of walking on bumpy roads and reduces damage to the joint motors.

Description

Technical Field

[0001] This invention relates to the field of robotics, specifically to a damped adjustable robot leg system and its control method. Background Technology

[0002] Wheel-legged robots, also known as wheel-legged robots, combine the characteristics of wheeled and legged robots. Wheeled robots have limited mobility on muddy and rugged terrain and struggle to overcome obstacles, while legged mobile robots have weak load-bearing capacity and suffer from slow speed, low efficiency, and unstable walking on flat surfaces. Combining wheeled and legged systems, to some extent, allows for the simultaneous achievement of the high efficiency and speed of wheels and the adaptability of legs to complex terrain. Currently, most legged mobile robots on the market lack shock absorption systems, relying primarily on the material of the wheels to reduce impact. However, this provides limited cushioning and lacks the ability to adjust damping for different loads, resulting in inaccurate movement trajectories and significantly reduced motor lifespan.

[0003] To address the issue of poor shock absorption in existing wheeled robots, patent application CN112141236A, entitled "A Wheeled Robot Leg System with Shock Absorption Function," provides a cushioning system for the legs of a wheeled robot. This system can solve the problem of high ground impact when the robot moves forward on wheels. However, the cushioning structure is a passively controlled mechanical structure that cannot adjust the damping. Therefore, it cannot meet the cushioning requirements under different loads for heavy-duty robots. Summary of the Invention

[0004] In view of this, the present invention provides a damped adjustable robot leg system and its control method, which can not only increase the robot's obstacle crossing ability when walking on wheels, but also reduce the vibration of walking on bumpy roads and reduce the damage to the joint motors.

[0005] The technical solution adopted in this invention is as follows:

[0006] A damped adjustable robotic leg system includes a thigh, a lower leg, a link, an adjustable damper, a wheel, and a wheel-side motor;

[0007] One end of the thigh is hinged to one end of the lower leg, and the lower leg is hinged to the other end of the thigh via a connecting rod, forming a parallelogram mechanism; the wheel foot is located at the other end of the lower leg, and the wheel-side motor is fixed to the side of the wheel foot to drive the movement of the wheel foot; the adjustable damper is fixed between the wheel-side motor and the other end of the lower leg; the adjustable damper can adjust the damping of the leg system, and when the adjustable damper is locked, the leg system is in a fully rigid state.

[0008] Furthermore, the adjustable damper includes a main oil chamber, a side oil chamber, an energy storage spring, a T-shaped push rod, a base, a conical valve body, and a drive motor;

[0009] The horizontal part of the T-shaped push rod slides against the inner wall of the main oil chamber, dividing the main oil chamber into an upper oil chamber and a lower oil chamber. The bottom end of the vertical part of the T-shaped push rod is fixed to the base. The energy storage spring is sleeved on the outside of the vertical part of the T-shaped push rod and press-fitted between the bottom surface of the main oil chamber and the upper surface of the base. The measuring oil chamber is located on the side of the main oil chamber. The measuring oil chamber is divided into an upper side oil chamber and a lower side oil chamber by a partition plate inside. The upper side oil chamber and the lower side oil chamber are respectively connected to the upper oil chamber and the lower oil chamber. The partition plate is provided with a conical through hole with the small diameter end of the conical through hole facing downward, for cooperating with the conical valve body. The drive motor drives the conical valve body to move up and down, adjusting the opening between the conical valve body and the conical through hole.

[0010] Furthermore, the main oil chamber includes an upper oil chamber cover, a lower oil chamber cover, and a main oil chamber body;

[0011] The upper and lower covers of the oil chamber are respectively encapsulated at the upper and lower ends of the main oil chamber. The lower cover of the oil chamber is provided with a limiting ring, which includes an inner ring and an outer ring. It is used to limit one end of the energy storage spring between the inner and outer rings. At the same time, the lower end face of the limiting ring contacts the upper surface of the base to limit the T-shaped push rod.

[0012] A damping-adjustable robot leg system control method is provided for controlling the aforementioned robot leg system. Damping is adjusted by controlling the opening between the conical valve body and the conical through hole, so that the leg system adapts to the working conditions. When the adjustable damper is locked, the leg system is in a fully rigid state.

[0013] Furthermore, the method for controlling the opening size is as follows:

[0014] Before the robot starts walking, the drive motor actively controls the conical valve body based on the robot's load, the road condition prediction of the map construction, the robot's starting gait, and the robot's gait prediction. During the robot's walking, the opening between the conical valve body and the conical through hole is adjusted in real time based on the real-time feedback of load changes, the actual road conditions, the real-time gait changes, and the road condition prediction of the route planning, in order to adapt to the gait changes of the robot's leg system.

[0015] Furthermore, when the load increases, the damping coefficient of the adjustable damper increases; when the load decreases, the damping coefficient of the adjustable damper automatically decreases proportionally.

[0016] Beneficial effects:

[0017] 1. In view of the problem that the cushioning structure of the legs of existing legged robots on the market is not effective, the present invention provides a robot leg system with adjustable damping and its control method, which can not only increase the robot's obstacle crossing ability when walking on wheels, but also reduce the vibration when walking on bumpy roads and reduce the damage to the joint motors.

[0018] Secondly, the adjustable damper provided by the present invention can be locked so that the leg system can reach a fully rigid state under certain conditions.

[0019] 2. To address the issue of non-adjustable damping in existing robot leg systems, the robot leg system provided by this invention is equipped with a hydraulic adjustable damper, which can adjust the damping according to the robot's road conditions, gait, and load. This adjustability allows the leg system to better control vibration, swaying, or other forms of dynamic response, thereby helping the control system to better adapt to different working conditions and improve the system's stability and responsiveness.

[0020] 3. The energy storage spring of the leg and foot system of the present invention has an elastic energy storage function and can play a propulsive role when the foot leaves the ground. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0022] Figure 2 This is a schematic diagram of an adjustable damper.

[0023] Figure 3 Right view of the adjustable damper.

[0024] Figure 4 for Figure 3 Sectional view along the AA direction.

[0025] Figure 5 This is a flowchart of the method for controlling the opening size.

[0026] Among them, 1-oil chamber upper cover, 2-main oil chamber body, 3-oil chamber lower cover, 4-energy storage spring, 5-T-shaped push rod, 6-base, 7-side cover, 8-conical valve body, 9-side chamber upper cover, 10-drive motor, 11-thigh, 12-lower leg, 13-connecting rod, 14-adjustable damper, 15-wheel foot, 16-wheel-side motor, 17-upper oil chamber, 18-lower oil chamber. Detailed Implementation

[0027] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] This invention provides a damped adjustable robotic leg system, including a thigh 11, a lower leg 12, a connecting rod 13, an adjustable damper 14, wheel feet 15, and a wheel-side motor 16, as shown below. Figure 1 As shown.

[0029] One end of the thigh 11 is hinged to one end of the lower leg 12, while the lower leg 12 is hinged to the other end of the thigh 11 via a connecting rod 13, forming a parallelogram mechanism; the wheel foot 15 is located at the other end of the lower leg 12, and the wheel-side motor 16 is fixed to the side of the wheel foot 15 to drive the wheel foot 15 to move; the adjustable damper 14 is fixed between the wheel-side motor 16 and the other end of the lower leg 12; the adjustable damper 14 can adjust the damping of the leg system, and when the adjustable damper 14 is locked, the leg system is in a fully rigid state.

[0030] The adjustable damper 14 is a hydraulically adjustable damper, specifically, as shown in... Figures 2-4 As shown, the adjustable damper 14 includes a main oil chamber, a side oil chamber, an energy storage spring 4, a T-shaped push rod 5, a base 6, a conical valve body 8, and a drive motor 10.

[0031] The horizontal part of the T-shaped push rod 5 slides against the inner wall of the main oil chamber, dividing the main oil chamber into an upper oil chamber 17 and a lower oil chamber 18. The bottom of the vertical part of the T-shaped push rod 5 is fixed to the base 6. The energy storage spring 4 is sleeved on the outside of the vertical part of the T-shaped push rod 5 and pressed between the bottom surface of the main oil chamber and the upper surface of the base 6 (only in contact, not fixed). The measuring oil chamber is located on the side of the main oil chamber. The measuring oil chamber is divided into an upper oil chamber and a lower oil chamber by a partition plate inside. The upper oil chamber and the lower oil chamber are connected to the upper oil chamber 17 and the lower oil chamber 18, respectively. The partition plate is provided with a conical through hole with the small diameter end of the conical through hole facing down, which is used to cooperate with the conical valve body 8. The drive motor 10 drives the conical valve body 8 to move up and down, adjusting the opening between the conical valve body 8 and the conical through hole. The opening is small and the damping is large.

[0032] Preferably, the main oil chamber includes an upper cover 1, a lower cover 3, and a main oil chamber body 2. The upper cover 1 and the lower cover 3 are respectively encapsulated at the upper and lower ends of the main oil chamber body 2. The lower cover 3 is provided with a limiting ring, which includes an inner ring and an outer ring, used to limit one end of the energy storage spring 4 between the inner ring and the outer ring. At the same time, the lower end face of the limiting ring contacts the upper surface of the base 6 to limit the T-shaped push rod 5. The upper cover 1 is connected to the end of the lower leg 12, and the base 6 is fixed to the wheel-side motor 16.

[0033] The drive motor 10 is fixed to the side cover 9 of the side oil chamber, and the upper end of the conical valve body 8 passes through the side cover 9 and is connected to the drive motor 10. The side of the side oil chamber is closed by the side cover 7.

[0034] When the foot touches the ground, the reaction force of the ground on the foot pushes the T-shaped push rod 5 upward. The oil in the upper oil chamber 17 flows through the conical through-hole on the partition plate to the lower side oil chamber 18. The energy storage spring 4 is compressed as the T-shaped push rod 5 moves upward. When the base 6 contacts the lower cover 3 of the damper oil chamber, it is the limit position of the upward movement of the T-shaped push rod 5. The lower cover 3 of the damper oil chamber has the function of stopping the movement and protecting the energy storage spring 4. When the T-shaped push rod 5 moves downward, the oil in the lower oil chamber 18 flows through the conical through-hole on the partition plate to the upper side oil chamber 17 and then enters the upper oil chamber 17 of the main oil chamber. The energy storage spring 4 releases its elastic potential energy, increasing the force of the foot pushing the ground. The drive motor 10 can control the opening of the conical valve body 8, thereby adjusting the damping coefficient of the damper.

[0035] The present invention also provides a control method for a robot leg system with adjustable damping, which is used to control the above-mentioned robot leg system. The damping is adjusted by controlling the opening between the conical valve body 8 and the conical through hole, so that the leg system can adapt to the working conditions. When the adjustable damper 14 is locked, that is, when the conical valve body 8 and the conical through hole are closed, the leg system is in a fully rigid state.

[0036] Generally, the larger the damping coefficient of a damper, the better the damping effect. The damping coefficient can be calculated using the following formula:

[0037] D = c × M

[0038] In the formula, D is the damping coefficient, c is the damping ratio of the damper, and M is the mass of the structure.

[0039] When the load increases, the damping coefficient of the adjustable damper 14 increases; when the load decreases, the damping coefficient of the adjustable damper 14 automatically decreases proportionally.

[0040] Specifically, the opening degree control between the conical valve body 8 and the conical through-hole consists of two parts: active control and passive adjustment. The opening degree control method is as follows: Figure 5 As shown in the figure, the conical valve is the conical valve body 8. Before the robot starts walking, the drive motor 10 actively controls the conical valve body 8 based on the robot's load, the road condition prediction of the map construction, the robot's starting gait, and the robot's gait prediction. During the robot's walking, the opening between the conical valve body 8 and the conical through hole is adjusted in real time based on the real-time load change feedback, the actual road condition feedback, the real-time gait change feedback, and the road condition prediction of the route planning, in order to adapt to the gait changes of the robot's leg system.

[0041] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A damped adjustable robotic leg system, characterized in that, Includes thigh, calf, connecting rod, adjustable damper, wheel foot and wheel-side motor; One end of the thigh is hinged to one end of the lower leg, and the lower leg is hinged to the other end of the thigh via a connecting rod, forming a parallelogram mechanism; the wheel foot is located at the other end of the lower leg, the wheel-side motor is fixed to the side of the wheel foot for driving the wheel foot's movement, and the adjustable damper is fixed between the wheel-side motor and the other end of the lower leg; the adjustable damper can adjust the damping of the leg system, and when the adjustable damper is locked, the leg system is in a fully rigid state; The adjustable damper includes a main oil chamber, a side oil chamber, an energy storage spring, a T-shaped push rod, a base, a conical valve body, and a drive motor. The horizontal part of the T-shaped push rod slides against the inner wall of the main oil chamber, dividing the main oil chamber into an upper oil chamber and a lower oil chamber. The bottom end of the vertical part of the T-shaped push rod is fixed to the base. The energy storage spring is sleeved on the outside of the vertical part of the T-shaped push rod and press-fitted between the bottom surface of the main oil chamber and the upper surface of the base. The side oil chamber is located on the side of the main oil chamber. The side oil chamber is divided into an upper side oil chamber and a lower side oil chamber by a partition plate inside. The upper side oil chamber and the lower side oil chamber are respectively connected to the upper oil chamber and the lower oil chamber. The partition plate is provided with a tapered through hole with the small diameter end of the tapered through hole facing downwards, for cooperating with the tapered valve body. The drive motor drives the tapered valve body to move up and down, adjusting the opening between the tapered valve body and the tapered through hole. The main oil chamber includes an upper cover, a lower cover, and a main oil chamber body; The upper and lower covers of the oil chamber are respectively encapsulated at the upper and lower ends of the main oil chamber. The lower cover of the oil chamber is provided with a limiting ring, which includes an inner ring and an outer ring. It is used to limit one end of the energy storage spring between the inner and outer rings. At the same time, the lower end face of the limiting ring contacts the upper surface of the base to limit the T-shaped push rod.

2. A control method for a robot leg system with adjustable damping, characterized in that, For controlling the robot leg system as described in claim 1, the damping is adjusted by controlling the opening between the conical valve body and the conical through hole, so that the leg system adapts to the working conditions; when the adjustable damper is locked, the leg system is in a fully rigid state.

3. The control method for a damped adjustable robot leg system as described in claim 2, characterized in that, The method for controlling the opening size is as follows: Before the robot starts walking, the drive motor actively controls the conical valve body based on the robot's load, the road condition prediction of the map construction, the robot's starting gait, and the robot's gait prediction. During the robot's walking, the opening between the conical valve body and the conical through hole is adjusted in real time based on the real-time feedback of load changes, the actual road conditions, the real-time gait changes, and the road condition prediction of the route planning, in order to adapt to the gait changes of the robot's leg system.

4. The control method for a damped adjustable robot leg system as described in claim 2 or 3, characterized in that, When the load increases, the damping coefficient of the adjustable damper increases; when the load decreases, the damping coefficient of the adjustable damper automatically decreases proportionally.

Images