Hydraulic simulation device for foot sole contact environment of foot type robot and control method of hydraulic simulation device

Abstract

The invention provides a foot type robot foot bottom contact environment hydraulic simulation device and a control method thereof, and relates to the field of foot type robots, the foot type robot foot bottom contact environment hydraulic simulation device comprises a hydraulic driving assembly, a vertical moving assembly and a horizontal overturning assembly, the hydraulic driving assembly comprises a vertical driving unit and an inclined driving unit, each driving unit comprises a flow servo valve, a displacement sensor, a force sensor, a piston rod and a connecting piece, the bottom end of the connector is connected with the top end of the piston rod through the force sensor, the position of a valve element is adjusted through the flow servo valve, and then the displacement of the piston rod in the vertical driving unit is controlled. By adjusting impedance mass, rigidity and damping parameters of each vertical driving unit, simulation of pavements with different softness such as sand and stone roads is realized, and by matching of the hydraulic driving assembly, the vertical moving assembly and the horizontal overturning assembly, walking and obstacle crossing modes of the soft pavements at different inclination angles are simulated, and motion modes are automatically switched.

Description

Technical Field

[0001] The present invention relates to the field of foot-type robots, and in particular to a hydraulic simulation device for a foot-type robot's sole contact environment and a control method thereof. Background Art

[0002] In the development of modern robotics technology, the research on bionic legged robots has attracted much attention. Compared with traditional wheeled or tracked robots, legged robots have the characteristics of discontinuous support and are more capable of moving on complex terrain. Therefore, they have shown broad application prospects in disaster relief, space exploration, military reconnaissance and other fields, and have become a research hotspot in the field of robotics.

[0003] The operational capabilities of a legged robot are directly related to the contact environment of its foot. Different terrain conditions, such as stairs, sand, and stone paths, can significantly impact the robot's locomotion. Existing environmental simulation devices often only simulate a single type of road surface, making them inadequate for testing legged robots in diverse terrains. To realistically simulate the effects of diverse outdoor road environments on robot control, a hydraulic simulation device for the contact environment of a legged robot's foot and its control method are necessary. Summary of the Invention

[0004] To address the shortcomings of the prior art, the present invention provides a hydraulic simulation device for the sole contact environment of a legged robot and its control method. By adjusting the impedance, mass, stiffness, and damping parameters of each vertical drive unit, the device can simulate surfaces of varying softness, such as sand and stone roads. Through the coordination of the hydraulic drive assembly, vertical movement assembly, and horizontal flip assembly, the device can simulate walking on soft surfaces and overcoming obstacles at varying inclination angles, while also enabling autonomous switching between motion modes. This addresses the problem that most existing environmental simulation devices can only simulate a single operating condition.

[0005] The present invention provides a hydraulic simulation device for the sole contact environment of a foot-type robot, which includes a hydraulic drive component, a vertical moving component and a horizontal flip component. The vertical moving component includes a moving plate, a guide column, a sleeve, a base and a hydraulic drive unit. The bottom end of the moving plate is connected to the first end of the guide column, the second end of the guide column is slidably connected to the sleeve, the first end of the sleeve is connected to the base, and the base is arranged on the flip plate; the horizontal flip component includes a flip plate, a support seat and a tilting drive unit. The flip plate is connected to the top end of the support seat by a hinge, the base of the tilting drive unit is rotatably connected to the middle and lower part of the support seat, and the second piston rod of the tilting drive unit is rotatably connected to the middle of the flip plate through a connector; the hydraulic drive component includes multiple vertical Drive unit and tilt drive unit, multiple vertical drive units are set at the corners of the simulation platform, each drive unit includes a flow servo valve, a displacement sensor, a force sensor, a first piston rod, a second piston rod and a support member, the bottom end of the connector is connected to the top end of the first piston rod through the force sensor, the support member is set at the first end of the displacement sensor, and the second end of the displacement sensor is connected to the cylinder wall of the tilt drive unit and the vertical drive unit through a limit sleeve. The valve core position is adjusted by the flow servo valve to control the inlet and outlet oil flows, thereby changing the displacement x of the piston rod in the drive unit; wherein the Laplace transform value of the displacement change caused by the force acting on the active dynamic compliance control in the outer loop of the control system of the hydraulic drive component is:

[0006]

[0007] Where ΔX is the Laplace transform value of the piston rod displacement x in the drive unit, ΔF is the force acting on the vertical drive unit, and Z is the displacement of the piston rod in the drive unit. D is the expected impedance characteristic of the vertical drive unit, and s is the Laplace operator.

[0008] Preferably, it also includes a fastening assembly, which includes a vertical drive member, a tilt drive member, a base, a connecting member and a fixed shaft. The two ends of the vertical drive member are respectively rotatably connected to the movable plate and the connecting plate, the two ends of the tilt drive member are respectively rotatably connected to the flip plate and the base, and the connecting head is rotatably connected to the connecting member through the fixed shaft.

[0009] Preferably, the inner loop of the control system of the hydraulic drive component is a position closed-loop control, and the load displacement is detected in real time by a displacement sensor, and the signal is fed back to the controller. The control system performs position closed-loop control through a PID algorithm to control the vertical height. When the simulated road surface rises, high-pressure oil is passed into the rodless cavity of the hydraulic drive component, and the rod cavity of the hydraulic drive component is connected to the low-pressure oil and realizes oil return, so that the simulated platform rises.

[0010] Preferably, the outer loop of the control system of the hydraulic drive component is impedance controlled, and the load force is measured by a force sensor, and the force is fed back to the hydraulic drive component control system. The outer loop obtains the position correction amount according to the set impedance mass, stiffness and damping parameters, and the inner loop controls the load displacement through PID to be close to the corrected expected displacement, thereby adjusting the softness of the foot end of the legged robot contacting the road surface.

[0011] Preferably, the force f acting on the active dynamic compliance control in the outer loop of the control system of the hydraulic drive assembly is:

[0012]

[0013] Where K D is the expected stiffness of the vertical drive unit, C D is the desired damping of the vertical drive unit, m D is the expected mass of the vertical drive unit, and x is the displacement of the piston rod in the drive unit.

[0014] A second aspect of the present invention provides a control method for a hydraulic simulation device for a foot-type robot's sole contact environment. By cooperating with a hydraulic drive component, a vertical movement component, and a horizontal flip component, the device simulates walking on soft surfaces and overcoming obstacles at different inclination angles and autonomously switches between motion modes. The motion modes include a climbing mode, a walking mode, and an obstacle-crossing mode. Specifically,

[0015] Climbing mode: The flow servo valve controls the high-pressure chamber to connect to the rodless chamber of the tilt hydraulic unit, and the drive unit actively extends to load. The horizontal flip assembly flips to form a tilt angle on the plantar simulation platform. The flow servo valve controls the drive unit to actively extend and retract, causing the plantar simulation platform to tilt at an angle, thus simulating different road slopes.

[0016] In a preferred embodiment, in the climbing mode, the displacement of the drive unit is:

[0017] l BC =l0+Δx p

[0018] Where, l BC is the total length of the drive unit, l0 is the initial length of the drive unit, Δx p To change the length of the drive unit, the flip angle θ of the horizontal flip component is:

[0019]

[0020] Where, l AB is the distance from the hinge center to the tail of the drive unit, l AC is the distance from the hinge center to the spherical bearing center.

[0021] In a preferred embodiment, in walking mode, a flow servo valve controls the tilt drive unit to keep the flip plate horizontal, while each vertical drive unit performs impedance control to simulate road surface quality, stiffness, and damping. When the foot of the legged robot contacts the foot simulation platform, the impedance control causes the platform to move vertically downward, allowing all four limbs to follow suit. By adjusting mass, stiffness, and damping parameters, the robot simulates walking on surfaces of varying softness.

[0022] In a preferred embodiment, in the obstacle crossing mode, the tilt drive unit is controlled by the flow servo valve to make the flip plate horizontal, and each vertical drive unit performs inner ring position control. By controlling the displacement of each vertical drive unit, obstacles of different heights are simulated.

[0023] Compared with the prior art, the beneficial effects of the present invention are embodied in that: the hydraulic simulation device for the sole contact environment of a foot-type robot of the present invention realizes the simulation of roads with different softness, such as sand and stone roads, by adjusting the impedance mass, stiffness and damping parameters of each vertical drive unit. Through the cooperation of the hydraulic drive component, the vertical moving component and the horizontal flip component, it simulates walking on soft roads and crossing obstacle modes at different inclination angles and autonomously switches the movement mode, thereby solving the problem that most existing environmental simulation devices usually simulate a single working condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the overall structure of the hydraulic simulation device for the sole contact environment of a foot-type robot according to the present invention;

[0025] Figure 2 Schematic diagram of the structure of the vertical drive unit in the present invention;

[0026] Figure 3 Schematic diagram of the structure of the tilt drive unit in the present invention;

[0027] Figure 4 Schematic diagram of the hydraulic simulation device for the sole contact environment of a foot-type robot in the climbing model mode of the present invention;

[0028] Figure 5 This is a posture diagram of the hydraulic simulation device for the sole contact environment of a foot-type robot in the climbing model mode of the present invention;

[0029] Figure 6 This is a schematic diagram of the structure of the cooperation of the drive units in the hydraulic drive assembly of the present invention;

[0030] Figure 7 is a characteristic diagram of the mass-spring-damper system in the hydraulic control system of the present invention;

[0031] Figure 8 This is a control diagram of the inner loop position control and outer loop impedance control of the hydraulic control system of the present invention;

[0032] Figure 9 Schematic diagram of the hydraulic control system of the hydraulic simulation device for the sole contact environment of a foot-type robot according to the present invention.

[0033] Main reference numerals:

[0034] 1. Simulation platform; 2. Moving plate; 3. Guide column; 4. Sleeve; 5. Base; 6. Oil source; 7. Hinge; 8. Connecting plate; 9. Flip plate; 10. Support seat; 11. Tilt drive unit; 12. Vertical drive unit; 13. Foot robot; 14. Connector; 15. First piston rod; 16. Vertical drive member; 17. Tilt drive member; 18. Second piston rod; 19. Joint bearing; 20. Base; 21. Connecting member; 22. Fixed shaft; 23. Force sensor; 24. Flow servo valve; 25. Support member; 26. Displacement sensor. DETAILED DESCRIPTION

[0035] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0036] The hydraulic simulation device for the sole contact environment of a foot-type robot of the present invention is as follows: Figure 1 As shown, it includes a hydraulic drive component, a vertical moving component and a horizontal flipping component. The vertical moving component includes a moving plate 2, a guide column 3, a sleeve 4, a base 5 and a hydraulic drive unit 12. The bottom end of the moving plate 2 is connected to the first end of the guide column 3, the second end of the guide column 3 is slidably connected to the sleeve 4, and the guide column 3 is slidably connected to the sleeve 4. The first end of the sleeve 4 is connected to the base 5, and the base 5 is arranged on the flip plate 9. The horizontal flipping component includes a flip plate 9, a support seat 10 and a tilting drive unit 11. The flip plate 9 is connected to the top of the support seat 10 by a hinge 7, the base of the tilting drive unit 11 is rotatably connected to the middle and lower part of the support seat 10, and the second piston rod 18 of the tilting drive unit 11 is rotatably connected to the middle part of the flip plate 9 through a connector 14.

[0037] like Figure 2 、 Figure 6 and Figure 9 As shown, the hydraulic drive assembly includes multiple vertical drive units 12 and one tilt drive unit 11. The multiple vertical drive units 12 are arranged at the corners of the simulation platform 1. Each drive unit includes a flow servo valve 24, a displacement sensor 26, a force sensor 23, a first piston rod 15, a second piston rod 18 and a support member 25. The bottom end of the connecting head 14 is connected to the top end of the first piston rod 15 through the force sensor 23. The support member 25 is arranged at the first end of the displacement sensor 26. The second end of the displacement sensor 26 is connected to the cylinder wall of the tilt drive unit 11 and the vertical drive unit 12 through a limit sleeve. The valve core position is adjusted by the flow servo valve 24 to control the inlet and outlet oil flow, thereby changing the displacement of the piston rod in the vertical drive unit 12.

[0038] In the outer loop of the control system of the hydraulic drive component, the Laplace transform value of the displacement caused by the force acting on the active dynamic compliance control is:

[0039]

[0040] Where ΔX is the Laplace transform value of the piston rod displacement x in the drive unit, ΔF is the force acting on the vertical drive unit, and Z is the displacement of the piston rod in the drive unit. D is the expected impedance characteristic of the vertical drive unit, and s is the Laplace operator.

[0041] like Figure 3 As shown, it also includes a fastening assembly, which includes a vertical drive member 16, a tilt drive member 17, a base 20, a connecting member 21 and a fixed shaft 22. The two ends of the vertical drive member 16 are respectively rotatably connected to the movable plate 2 and the connecting plate 8, the two ends of the tilt drive member 17 are respectively rotatably connected to the flip plate 9 and the base 20, and the connecting head 14 is rotatably connected to the connecting member 21 through the fixed shaft 22.

[0042] like Figure 7 and Figure 8 As shown, the inner loop of the control system of the hydraulic drive component is a position closed-loop control. The load displacement is detected in real time by the displacement sensor 26, and the signal is fed back to the controller. The control system performs position closed-loop control through the PID algorithm to control the vertical height. When the simulated road surface rises, high-pressure oil is passed into the rodless cavity of the hydraulic drive component, and the rod cavity of the hydraulic drive component is connected to the low-pressure oil and realizes oil return, so that the simulated platform 1 rises.

[0043] The outer loop of the control system of the hydraulic drive component is impedance control. The load force is measured by the force sensor 23, and the force is fed back to the hydraulic drive component control system. The outer loop obtains the position correction value based on the set impedance mass, stiffness and damping parameters. The inner loop controls the load displacement through PID to be close to the corrected expected displacement, and adjusts the softness of the foot end of the foot robot 13 contacting the road surface.

[0044] The force f acting on the active dynamic compliance control in the outer loop of the control system of the hydraulic drive component is:

[0045]

[0046] Where K D is the expected stiffness of the vertical drive unit, C D is the desired damping of the vertical drive unit, m D is the expected mass of the vertical drive unit, and x is the displacement of the piston rod in the drive unit.

[0047] In a preferred embodiment, the present invention provides a control method for a hydraulic simulation device for the sole contact environment of a legged robot. By cooperating with a hydraulic drive component, a vertical movement component, and a horizontal flip component, the device simulates walking on soft surfaces and overcoming obstacles at different inclination angles and autonomously switches between motion modes. The motion modes include climbing mode, walking mode, and overcoming obstacle mode. Specifically,

[0048] like Figure 4 and Figure 5 As shown, in climbing mode, the foot contact environment hydraulic simulator is connected to the oil source 6. The flow servo valve 24 controls the high-pressure chamber to connect to the rodless chamber of the tilt hydraulic unit 11, causing the drive unit to actively extend and load. The horizontal flip assembly performs a flipping motion, causing the foot simulation platform to tilt. The flow servo valve 24 controls the active extension and retraction of the drive unit. By adjusting the tilt angle of the foot simulation platform 1, simulation of different road slopes can be achieved.

[0049] In climbing mode, the drive unit displacement is:

[0050] l BC =l0+Δx p

[0051] Where, l BC is the total length of the drive unit, l0 is the initial length of the drive unit, Δx p To change the length of the drive unit, the flip angle θ of the horizontal flip component is:

[0052]

[0053] Where, l AB is the distance from the hinge center to the tail of the drive unit, l AC It is the distance from the hinge center to the center of the spherical plain bearing 19.

[0054] In walking mode, the hydraulic simulation device for the plantar contact environment is connected to the oil source 6 and controls the tilt drive unit 11 via the flow servo valve 24, keeping the flip plate 9 horizontal. Each vertical drive unit 12 performs impedance control to simulate the road surface quality, stiffness, and damping. When the foot of the legged robot 13 contacts the plantar simulation platform, the impedance control causes the platform to move vertically downward, causing the limbs to follow the movement synchronously. By adjusting the mass, stiffness, and damping parameters, walking on surfaces of varying softness is simulated.

[0055] In obstacle crossing mode, the foot contact environment hydraulic simulation device is connected to the oil source 6 and controls the tilt drive unit 11 via the flow servo valve 24 to keep the flip plate 9 horizontal. Each vertical drive unit 12 is position-controlled, and by controlling the displacement of each vertical drive unit 12, obstacles of different heights can be simulated.

[0056] The present invention's hydraulic simulation device for the plantar contact environment of a legged robot and its control method simulates surfaces of varying softness, such as sand and stone roads, by adjusting the impedance, mass, stiffness, and damping parameters of each vertical drive unit. Through the coordination of the hydraulic drive assembly, vertical movement assembly, and horizontal flip assembly, the device simulates walking on soft surfaces and overcoming obstacles at varying inclination angles, while also autonomously switching between motion modes. This device addresses the problem of most existing environmental simulation devices being limited to simulating a single operating condition. It can more realistically simulate the actual operating conditions of a legged robot under various complex load conditions, providing a reliable testing platform for optimizing and verifying the performance of legged robots under different operating conditions.

[0057] The above embodiments are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A hydraulic simulation device for the sole contact environment of a foot-type robot, characterized by: It includes a hydraulic drive component, a vertical movement component and a horizontal flip component. The vertical moving assembly includes a moving plate, a guide column, a sleeve, a base and a hydraulic drive unit. The bottom end of the moving plate is connected to the first end of the guide column, the second end of the guide column is slidably connected to the sleeve, the first end of the sleeve is connected to the base, and the base is arranged on the flip plate; The horizontal flip assembly includes a flip plate, a support base and a tilt drive unit. The flip plate is connected to the top of the support base through a hinge. The base of the tilt drive unit is rotatably connected to the middle and lower part of the support base. The second piston rod of the tilt drive unit is rotatably connected to the middle of the flip plate through a connector. The hydraulic drive assembly includes multiple vertical drive units and tilt drive units. The multiple vertical drive units are arranged at the corners of the simulation platform. Each drive unit includes a flow servo valve, a displacement sensor, a force sensor, a first piston rod, a second piston rod, and a support member. The bottom end of the connector is connected to the top end of the first piston rod via the force sensor. The support member is arranged at the first end of the displacement sensor. The second end of the displacement sensor is connected to the cylinder wall of the tilt drive unit and the vertical drive unit via a limit sleeve. The valve core position is adjusted by the flow servo valve to control the inlet and outlet oil flows, thereby changing the displacement x of the piston rod in the drive unit. Among them, the Laplace transform value of the displacement change caused by the force acting on the active dynamic compliance control in the outer loop of the control system of the hydraulic drive component is: Where ΔX is the Laplace transform value of the piston rod displacement x in the drive unit, ΔF is the force acting on the vertical drive unit, and Z is the displacement of the piston rod in the drive unit. D is the expected impedance characteristic of the vertical drive unit, and s is the Laplace operator.

2. The hydraulic simulation device for the sole contact environment of a legged robot according to claim 1, characterized in that: It also includes a fastening assembly, which includes a vertical drive member, a tilt drive member, a base, a connecting member and a fixed shaft. The two ends of the vertical drive member are respectively rotatably connected to the movable plate and the connecting plate, the two ends of the tilt drive member are respectively rotatably connected to the flip plate and the base, and the connecting head is rotatably connected to the connecting member through the fixed shaft.

3. The hydraulic simulation device for the sole contact environment of a legged robot according to claim 1, characterized in that: The inner loop of the control system of the hydraulic drive component is position closed-loop control. The load displacement is detected in real time through the displacement sensor, and the signal is fed back to the controller. The control system performs position closed-loop control through the PID algorithm to control the vertical height. When the simulated road surface rises, high-pressure oil is passed into the rodless cavity of the hydraulic drive component, and the rod cavity of the hydraulic drive component is connected to the low-pressure oil and realizes oil return, so that the simulated platform rises.

4. The hydraulic simulation device for the sole contact environment of a legged robot according to claim 1, characterized in that: The outer loop of the control system of the hydraulic drive component is impedance control. The load force is measured by a force sensor, and the force is fed back to the hydraulic drive component control system. The outer loop obtains the position correction value based on the set impedance mass, stiffness and damping parameters. The inner loop controls the load displacement through PID to approach the corrected expected displacement, and adjusts the softness of the foot end of the legged robot in contact with the road surface.

5. The hydraulic simulation device for the sole contact environment of a legged robot according to claim 4, characterized in that: The force f acting on the active dynamic compliance control in the outer loop of the control system of the hydraulic drive component is: Where K D is the expected stiffness of the vertical drive unit, C D is the desired damping of the vertical drive unit, m D is the expected mass of the vertical drive unit, and x is the displacement of the piston rod in the drive unit.

6. A control method for the hydraulic simulation device for the sole contact environment of a legged robot according to any one of claims 1 to 5, characterized in that: Through the cooperation of hydraulic drive components, vertical movement components and horizontal flip components, the robot can simulate walking on soft roads and crossing obstacles at different inclination angles and automatically switch motion modes. The motion modes include climbing mode, walking mode and crossing obstacle mode. Specifically: Climbing mode: The flow servo valve is used to control the high-pressure chamber to connect to the rodless chamber of the tilting hydraulic unit, and the drive unit actively extends to load; the horizontal flip assembly flips to form a tilt angle on the plantar simulation platform, and the flow servo valve is used to control the drive unit to actively extend and retract to make the plantar simulation platform tilt, thereby simulating different road slopes.

7. The control method of the hydraulic simulation device for the sole contact environment of a legged robot according to claim 6, characterized in that: In climbing mode, the drive unit displacement is: l BC =l0+Δx p Where, l BC is the total length of the drive unit, l0 is the initial length of the drive unit, Δx p To drive the unit length, The flip angle θ of the horizontal flip component is: Where, l AB is the distance from the hinge center to the tail of the drive unit, l AC is the distance from the hinge center to the spherical bearing center.

8. The control method of the hydraulic simulation device for the sole contact environment of a legged robot according to claim 6, characterized in that: In walking mode, the tilt drive unit is controlled by the flow servo valve to keep the flip plate horizontal, and each vertical drive unit performs impedance control to simulate the road quality, stiffness and damping; when the foot end of the legged robot contacts the plantar simulation platform, due to the existence of impedance control, the plantar simulation platform moves vertically downward, so that the limbs follow the movement synchronously, and walking on roads of different softness is simulated by adjusting the mass, stiffness and damping parameters.

9. The control method of the hydraulic simulation device for the sole contact environment of a legged robot according to claim 6, characterized in that: In the obstacle crossing mode, the tilt drive unit is controlled by the flow servo valve to make the flip plate horizontal, and each vertical drive unit performs inner ring position control. By controlling the displacement of each vertical drive unit, obstacles of different heights are simulated.

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