Method for testing equivalent stiffness and equivalent damping mapping matrix of hydraulic foot type robot

Abstract

The invention relates to a hydraulic foot type robot equivalent stiffness and equivalent damping mapping matrix test method, and belongs to the technical field of robot control and simulation, and the method comprises the steps: S1, carrying out the discrete sampling of the foot end interference force FL of a hydraulic robot, and obtaining the robot foot end interference force variable quantity at adjacent moments; s2, foot end displacement variation of the hydraulic robot at adjacent moments is obtained; s3, calculating the displacement variation of a joint driving unit; s4, the output force variation of the joint hydraulic driving unit of the hydraulic robot at adjacent moments is obtained; s5, the foot end force variable quantity of the hydraulic robot is obtained through positive static positive solution of the output force variable quantity of the joint hydraulic driving unit; s6, the foot end force variable quantity is accumulated and summed, and foot end disturbance force FL'is obtained; and S7, comparing the foot end interference force FL with the foot end interference force FL ', and judging whether the equivalent impedance stiffness and equivalent impedance damping mapping matrix is correct or not, so that the precision of the equivalent stiffness and equivalent damping mapping matrix can be verified, and the precision of the equivalent mapping matrix is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of robot control and simulation, and in particular relates to a method and system for testing equivalent stiffness and equivalent damping mapping matrices of a hydraulic foot robot. Background Art

[0002] Compared with other types of robots such as wheeled and tracked robots, legged robots can achieve discontinuous support and have stronger adaptability to unknown environments. Especially when combined with a hydraulic system with a high power-to-weight ratio, the load-bearing capacity of legged robots can be significantly improved, making them more suitable for field operations and heavy object transportation. At present, it has become one of the hot research areas in various countries. However, during the movement of hydraulic legged robots, impacts between the foot and the ground are inevitable, so compliant control is required to reduce the impact force generated by contact with the environment.

[0003] Compared with passive compliance control, active compliance control simulates passive spring dampers through algorithms and has higher environmental adaptability and adjustability. Impedance control is a common active compliance control method and is widely used in the compliance control of the legs of hydraulic footed robots. At present, common impedance control is performed in the Cartesian space of the foot end. By simulating the stiffness damping system at the foot end, the compliance effect of the leg foot end space can be achieved. However, there are two problems with impedance control at the foot end of the leg. First, the kinematic, static and dynamic solution processes will affect the response speed of the compliance control. Second, it is not conducive to the selection of the inner loop of impedance control for different joints in the new impedance configuration. Therefore, it is necessary to map the foot end impedance control to the joint space and simulate the stiffness damping system in the joint space.

[0004] However, the derivation of the equivalent impedance stiffness and equivalent impedance damping mapping matrices in Cartesian space and joint space is based on the idea of ​​microelement, that is, the equivalent mapping matrix is ​​more suitable for the working condition where the displacement change of the foot end of the hydraulic robot is small. But in most cases, the displacement of the robot foot end is large, which makes the equivalent mapping matrix have a large error in the verification process, affecting the verification accuracy of the equivalent mapping matrix. Therefore, a high-precision verification method for the equivalent impedance stiffness and equivalent impedance damping mapping matrix suitable for serial hydraulic foot robots is urgently needed. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a method for verifying the equivalent stiffness and equivalent damping mapping matrices in Cartesian space and joint space of an n-degree-of-freedom serial hydraulic legged robot based on the finite difference method. The method can verify the accuracy of the equivalent stiffness and equivalent damping mapping matrices, ensure the accuracy of the equivalent mapping matrices, and has good universality and can be applied to multiple fields.

[0006] To achieve the above object, the present invention discloses the following technical solution:

[0007] Specifically, on the one hand, the present invention provides a method for testing equivalent stiffness and equivalent damping mapping matrices of a hydraulic legged robot, which comprises the following steps:

[0008] S1, the hydraulic robot foot end interference force F L Discrete sampling is performed to obtain the change of the foot-end interference force of the hydraulic robot at adjacent moments ΔF L , the relationship is:

[0009] ΔF L =F L (t i +Δt)-F L (t i )

[0010] Where Δt is the sampling interval, t i is the i-th sampling moment, ΔF L is the change of the interference force at the foot end of the hydraulic robot at adjacent moments, F L is the disturbance force at the foot end of the hydraulic robot;

[0011] S2. The displacement change of the foot end of the hydraulic robot at adjacent moments is obtained by using the change of the disturbance force at the foot end of the hydraulic robot at adjacent moments and the Cartesian space impedance stiffness and impedance damping matrix of the foot end. c , the calculation formula is as follows:

[0012]

[0013] Among them, Z Dc is the foot end impedance characteristic parameter, Δx c is the displacement change of the foot end of the hydraulic robot at adjacent moments;

[0014] S3, the displacement change of the robot foot end is solved by inverse kinematics to obtain the displacement change of the joint drive unit Δx p , the relationship is:

[0015] Δx p =AJ + Δx c

[0016] Among them, J + is the pseudo-inverse matrix of the robot Jacobian matrix J, A is the configuration matrix, Δx p is the displacement change of the joint drive unit;

[0017] S4. Multiply the change in the output force of the joint hydraulic drive unit by the joint equivalent impedance characteristic parameter to obtain the change in the output force of the joint hydraulic drive unit at adjacent moments ΔF h , the relationship is:

[0018] ΔF h =Z Dh Δx p

[0019] Among them, Z Dh is the equivalent impedance characteristic parameter of the hydraulic drive unit, ΔF h It is the change in output force of the joint hydraulic drive unit at adjacent moments.

[0020] S5. The output force change of the robot joint hydraulic drive unit is solved by positive statics to obtain the robot foot end interference force ΔF′ L , the relationship is:

[0021]

[0022] Among them, J T is the transposed matrix of the robot Jacobian matrix J, (J T ) + For J T The generalized inverse matrix of , L is the robot link length matrix, ΔF′ L is the disturbance force on the robot foot obtained by positive statics solution, τ′ is the torque on the revolute joint;

[0023] S6. The foot-end disturbance force ΔF′ obtained when the hydraulic robot performs impedance control on the joint L The robot predicts the foot-end disturbance force F′ by adding the accumulated sum. L , the relationship is:

[0024]

[0025] Where N is the number of discrete samples, F′ L Predict the foot-end disturbance force for the robot obtained through prediction;

[0026] S7, the foot end interference force F L and the predicted foot end disturbance force F′ L Compare them, if the two are equal, the output equivalent impedance stiffness and equivalent impedance damping mapping matrix is ​​correct.

[0027] Preferably, the impedance characteristic parameter Z in step S2 Dc The expression is:

[0028] Z Dc =B c s+K c

[0029] Among them, B c is the Cartesian space damping matrix at the foot end, K c is the Cartesian space stiffness matrix of the foot end, and s is the Laplace operator.

[0030] Preferably, the impedance characteristic parameter Z Dh The expression is:

[0031] Z Dh =B h s+K h

[0032] Among them, B h is the equivalent damping matrix in joint space, K h is the equivalent stiffness matrix in joint space.

[0033] Preferably, in step S1 , Δt is 1 ms.

[0034] Preferably, as in step S7, the foot end interference force F L and the predicted foot end disturbance force F′ L If they are not equal, the equivalent impedance stiffness and equivalent impedance damping mapping matrix is ​​re-derived and steps S1-S6 are repeated for re-verification.

[0035] Preferably, the equivalent damping matrix B of the leg joint space of the hydraulic foot robot is h The exact relationship between it and the foot-end Cartesian spatial damping matrix Bc is:

[0036] B h =L -1 J T B c J A -1 .

[0037] Preferably, the equivalent stiffness matrix K of the leg joint space of the hydraulic foot robot is h The exact relationship between it and the foot-end Cartesian space stiffness matrix Kc is:

[0038] K h =L -1 (J T K c J+K s -K hs )A -1 .

[0039] On the other hand, the present invention provides a hydraulic foot robot equivalent stiffness and equivalent damping mapping matrix test system, which includes a hydraulic robot foot end interference force variation calculation unit at adjacent moments, a hydraulic robot foot end displacement variation calculation unit at adjacent moments, a joint drive unit displacement variation calculation unit, an adjacent moment joint hydraulic drive unit output force variation calculation unit, a robot foot end interference force calculation unit, a robot foot end interference calculation unit and a verification unit;

[0040] The hydraulic robot foot-end interference force variation calculation unit at adjacent moments is used to discretely sample the hydraulic robot foot-end interference force to obtain the hydraulic robot foot-end interference force variation at adjacent moments;

[0041] The foot end displacement variation calculation unit of the hydraulic robot at adjacent moments is used to obtain the foot end displacement variation of the hydraulic robot at adjacent moments by using the foot end interference force variation of the hydraulic robot at adjacent moments and the Cartesian space impedance stiffness and impedance damping matrix of the foot end;

[0042] The joint drive unit displacement variation calculation unit is used to obtain the joint drive unit displacement variation by solving the robot foot end displacement variation through inverse kinematics;

[0043] The output force variation calculation unit of the joint hydraulic drive unit at adjacent moments is used to multiply the output force variation of the joint hydraulic drive unit by the joint equivalent impedance characteristic parameter to obtain the output force variation of the joint hydraulic drive unit at adjacent moments;

[0044] The robot foot-end interference force calculation unit is used to obtain the robot foot-end interference force by solving the output force variation of the robot joint hydraulic drive unit through positive statics;

[0045] The robot foot-end interference unit is used to accumulate and sum the foot-end interference force obtained when the hydraulic robot performs impedance control on the joint to obtain the robot foot-end interference;

[0046] The verification unit is used to compare the foot-end disturbance force with the predicted foot-end disturbance force and output the comparison result.

[0047] Preferably, if the foot-end disturbance force is equal to the predicted foot-end disturbance force, the output equivalent impedance stiffness and equivalent impedance damping mapping matrix is ​​correct; if the foot-end disturbance force is not equal to the predicted foot-end disturbance force, the equivalent impedance stiffness and equivalent impedance damping mapping matrix is ​​re-derived and verified again.

[0048] Preferably, the present invention also provides a computer device, which comprises the above-mentioned hydraulic legged robot equivalent stiffness and equivalent damping mapping matrix testing system.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] (1) The present invention provides a verification method for the equivalent stiffness and equivalent damping mapping matrices in Cartesian space and joint space of an n-degree-of-freedom serial hydraulic legged robot based on the finite difference method, which can verify the accuracy of the equivalent stiffness and equivalent damping mapping matrices and ensure the accuracy of the equivalent mapping matrices.

[0051] (2) The hydraulic leg robot equivalent stiffness and equivalent damping mapping matrix verification method provided by the present invention has a wide range of applications and is a universal verification method that can be used for verification testing of robots with linearly driven joints of any degree of freedom to ensure the normal use of the robot.

[0052] (3) The verification accuracy of the hydraulic legged robot equivalent stiffness and equivalent damping mapping matrix verification method provided by the present invention can be adjusted manually. By increasing the sampling time interval, the verification accuracy of the equivalent mapping matrix can be reduced; by shortening the sampling time interval, the verification accuracy of the equivalent mapping matrix can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 is a flow chart of the overall method of the present invention;

[0054] Figure 2 Schematic diagram of a single-leg simulation model of a hydraulic footed robot of the present invention;

[0055] Figure 3 A schematic diagram of the single leg structure of the hydraulic foot robot of the present invention;

[0056] Figure 4 2 is a schematic diagram comparing the interference force of the foot end in the x direction of the hydraulic robot of the present invention;

[0057] Figure 5 It is a schematic diagram comparing the interference force of the foot end in the y direction of the hydraulic robot of the present invention.

[0058] Some of the drawings in the accompanying drawings are described as follows:

[0059] O is the knee joint, D is the ankle joint, θ1 is the rotation angle of the knee joint, θ2 is the rotation angle of the ankle joint, τ1 is the torque on the knee joint, τ2 is the torque on the ankle joint, F x The force at point F in the x direction, F y is the force at point F in the y direction, OD is the calf, DF is the foot end, AB is the total length of the hydraulic drive unit of the knee joint, and CE is the total length of the hydraulic drive unit of the ankle joint. DETAILED DESCRIPTION

[0060] The exemplary embodiments, features and aspects of the present invention will be described in detail below with reference to the accompanying drawings. The same reference numerals in the accompanying drawings represent elements with the same or similar functions. Although various aspects of the embodiments are shown in the accompanying drawings, the drawings are not necessarily drawn to scale unless otherwise specified.

[0061] The present invention provides a method for testing the equivalent stiffness and equivalent damping mapping matrix of an n-DOF serial hydraulic legged robot. The flow chart is as follows: Figure 1 As shown, it specifically includes the following steps:

[0062] S1: The hydraulic robot foot end disturbance force F L Discrete sampling is performed at 1ms intervals to obtain the change in the robot foot-end interference force at adjacent moments;

[0063] ΔF L =F L (t i +Δt)-F L (t i )

[0064] Where Δt is the sampling interval, t i is the i-th sampling moment, ΔF L is the change of the interference force at the foot end of the hydraulic robot at adjacent moments, F L is the disturbance force at the foot end of the hydraulic robot.

[0065] S2: Divide the change in the foot-end interference force by the foot-end impedance characteristic parameter to obtain the change in the foot-end displacement of the hydraulic robot at adjacent moments. The relationship is:

[0066]

[0067] Among them, Z Dc is the foot end impedance characteristic parameter, Δx c is the displacement change of the foot end of the hydraulic robot at adjacent moments.

[0068] Foot end impedance characteristic parameter Z Dc The expression is:

[0069] Z Dc =B c s+K c

[0070] Among them, B c is the Cartesian space damping matrix at the foot end, K c is the Cartesian space stiffness matrix of the foot end, and s is the Laplace operator.

[0071] S3: The displacement change of the robot foot end is solved by inverse kinematics to obtain the displacement change of the joint drive unit Δx p , the relationship is:

[0072] Δx p =AJ + Δx c

[0073] Among them, J + is the pseudo-inverse matrix of the robot Jacobian matrix J, A is the configuration matrix, Δx p is the displacement change of the joint drive unit.

[0074] S4: Divide the displacement change of the joint drive unit by the joint impedance characteristic parameter to obtain the output force change ΔF of the joint hydraulic drive unit of the hydraulic robot at adjacent moments h , the relationship is:

[0075] ΔF h =Z Dh Δx p

[0076] Among them, Z Dh is the equivalent impedance characteristic parameter of the hydraulic drive unit, ΔF h It is the change in output force of the joint hydraulic drive unit at adjacent moments.

[0077] Joint impedance characteristic parameter Z Dh The expression is:

[0078] Z Dh =B h s+K h

[0079] Among them, B h is the equivalent damping matrix in joint space, K h is the equivalent stiffness matrix in joint space.

[0080] S5: The change in the output force of the joint hydraulic drive unit is obtained by the statics forward solution to obtain the change in the hydraulic robot foot end force ΔF′ L , and the relationship is;

[0081]

[0082] Among them, J T is the transposed matrix of the robot Jacobian matrix J, (J T ) + For J T The generalized inverse matrix of , L is the robot link length matrix, ΔF′ L is the disturbance force on the robot foot obtained by positive statics solution, and τ′ is the torque on the revolute joint.

[0083] S6: The foot-end disturbance force ΔF′ obtained when the hydraulic robot performs impedance control on the joint L The robot predicts the foot-end disturbance force F′ by adding the accumulated sum. L , the relationship is:

[0084]

[0085] Where N is the number of discrete samples, F′ L is the robot foot disturbance force obtained by solving.

[0086] S7: The foot end interference force FL and foot end interference force F′ L By comparison, if the two are equal, the correctness of the equivalent impedance stiffness and equivalent impedance damping mapping matrix can be proved.

[0087] On the other hand, the present invention provides an equivalent stiffness and equivalent damping mapping matrix testing system for a hydraulic foot-type robot, which includes a calculation unit for the change in foot-end interference force of the hydraulic robot at adjacent moments, a calculation unit for the change in foot-end displacement of the hydraulic robot at adjacent moments, a calculation unit for the change in displacement of a joint drive unit, a calculation unit for the change in output force of a joint hydraulic drive unit at adjacent moments, a robot foot-end interference force calculation unit, a robot foot-end interference calculation unit, and a verification unit.

[0088] The hydraulic robot foot-end disturbance force variation calculation unit at adjacent moments is used for discretely sampling the hydraulic robot foot-end disturbance force to obtain the hydraulic robot foot-end disturbance force variation at adjacent moments.

[0089] The foot end displacement change calculation unit of the hydraulic robot at adjacent moments is used to obtain the foot end displacement change of the hydraulic robot at adjacent moments by using the foot end interference force change of the hydraulic robot at adjacent moments and the foot end Cartesian space impedance stiffness and impedance damping matrix.

[0090] The joint drive unit displacement variation calculation unit is used to obtain the joint drive unit displacement variation by solving the robot foot end displacement variation through inverse kinematics.

[0091] The output force variation calculation unit of the joint hydraulic drive unit at adjacent moments is used to multiply the output force variation of the joint hydraulic drive unit by the joint equivalent impedance characteristic parameter to obtain the output force variation of the joint hydraulic drive unit at adjacent moments.

[0092] The robot foot-end disturbance force calculation unit is used to obtain the robot foot-end disturbance force by solving the output force variation of the robot joint hydraulic drive unit through positive statics.

[0093] The robot foot-end interference unit is used to accumulate and sum the foot-end interference force obtained when the hydraulic robot performs impedance control on the joints to obtain the robot foot-end interference.

[0094] The verification unit is used to compare the foot-end disturbance force with the predicted foot-end disturbance force and output the comparison result.

[0095] Preferably, if the foot-end disturbance force is equal to the predicted foot-end disturbance force, the output equivalent impedance stiffness and equivalent impedance damping mapping matrix is ​​correct; if the foot-end disturbance force is not equal to the predicted foot-end disturbance force, the equivalent impedance stiffness and equivalent impedance damping mapping matrix is ​​re-derived and verified again.

[0096] Preferably, the present invention also provides a computer device of a test system for a hydraulic legged robot equivalent stiffness and equivalent damping mapping matrix test method, and the computer device includes the above-mentioned hydraulic legged robot equivalent stiffness and equivalent damping mapping matrix test system. Specific embodiments

[0098] This embodiment provides a method for testing the equivalent stiffness and equivalent damping mapping matrix of an n-DOF serial hydraulic legged robot, which is used for testing the equivalent stiffness and equivalent damping mapping matrix of a hydraulic legged robot. First, a schematic diagram of a serial hydraulic legged single leg structure is established, such as Figure 2 and Figure 3 As shown, this is used as an example of a specific expression in the mapping method embodiment. Figure 3 In the figure, O and D are the knee joint and ankle joint respectively. O is defined as the origin of the coordinate system. The positive direction of the x-axis is horizontal to the right, and the positive direction of the y-axis is vertical upward. The knee joint rotation angle θ1 is the angle between the shank OD and the negative direction of the y-axis. The ankle joint rotation angle θ2 is the angle between the extension line of the shank OD and the foot end DF. The counterclockwise direction of the rotation angle is defined as the positive direction. The angle between OB and OD is α, the angle between OA and the positive direction of the x-axis is β, AB and CE are the total extension lengths of the knee joint hydraulic drive unit and the ankle joint hydraulic drive unit respectively, and the initial lengths of the knee joint and ankle joint hydraulic drive units are respectively expressed as l 01 and l 02 , the position of point F is controlled by changing the extension length of the hydraulic drive unit of each joint. Figure 3 The values ​​of the structural parameters of the middle leg are shown in Table 1:

[0099] Table 1 Table of mechanical structure parameters of single leg of hydraulic foot robot

[0100]

[0101] According to the leg configuration of the hydraulically driven robot, the kinematic solution of the robot is:

[0102]

[0103] in, is the displacement of the foot in the x direction, is the displacement of the foot in the y direction.

[0104] Joint angle θ i Displacement Δx of the joint hydraulic drive unit p The relationship is:

[0105]

[0106] Among them, l 01 is the initial length of the knee joint hydraulic drive unit, l02 is the initial length of the ankle joint hydraulic drive unit, γ=∠AOC+∠BOD,

[0107] The inverse kinematics of the robot is:

[0108]

[0109] The Jacobian matrix of the robot is:

[0110]

[0111] According to the principle of virtual work, the static inverse solution of the robot is:

[0112]

[0113] Among them, τ1 is the moment on the knee joint, and τ2 is the moment on the ankle joint.

[0114] Joint torque τ i Force △F of hydraulic drive unit si The relationship between them is:

[0115]

[0116] Among them, △F s1 is the force on the knee joint hydraulic drive unit, △F s2 It is the ankle joint hydraulic drive unit that is subjected to force.

[0117] The positive solution of the robot statics is:

[0118]

[0119] The matrix K of the robot affected by the geometric configuration s It can be expressed as:

[0120]

[0121] Among them, K s The specific expressions of each matrix element are as follows:

[0122]

[0123] For the knee joint of the hydraulic foot robot, the area S of △OAB can be expressed as:

[0124]

[0125] Where L1 is the driving force arm of the knee joint hydraulic drive unit, and AB = l 01 +xp1.

[0126] According to the above formula, the driving force arm L1 of the knee joint hydraulic drive unit can be further expressed as:

[0127]

[0128] Define counterclockwise as the positive direction of the torque, then the driving force arm L1 of the knee joint hydraulic drive unit can be updated as:

[0129]

[0130] For the ankle joint of the hydraulic foot robot, the area S of △CDE can be expressed as:

[0131]

[0132] Where L2 is the driving force arm of the ankle joint hydraulic drive unit, and CD = l 02 +xp2.

[0133] According to the above formula, the driving force arm L2 of the ankle joint hydraulic drive unit can be further expressed as:

[0134]

[0135] Combining the expressions of the driving force arm L1 of the knee joint hydraulic drive unit and the driving force arm L2 of the ankle joint hydraulic drive unit, the robot configuration matrix link length matrix L is:

[0136]

[0137] The robot configuration matrix A is:

[0138]

[0139] The robot matrix K hs for:

[0140]

[0141] like Figure 3 The equivalent damping matrix B of the leg joint space of the hydraulic foot robot is shown in h The exact relationship between it and the foot-end Cartesian spatial damping matrix Bc is:

[0142] B h =L -1 J T B c J A -1 .

[0143] like Figure 3 The equivalent stiffness matrix K of the leg joint space of the hydraulic foot robot is shown as hThe exact relationship between it and the foot-end Cartesian space stiffness matrix Kc is:

[0144] K h =L -1 (J T K c J+K s -K hs )A -1

[0145] When a sinusoidal disturbance force of 2000sin(2πt)N is applied in the x direction of point F of the leg of the hydraulic footed robot, a sinusoidal disturbance force of 1500sin(2πt)N is applied in the y direction of point F, the Cartesian space stiffness matrix Kc in the x direction of point F is 100N / mm, the Cartesian space damping matrix Bc in the x direction of point F is 1Ns / mm, the Cartesian space stiffness matrix Kc in the y direction of point F is 75N / mm, and the Cartesian space damping matrix Bc in the y direction of point F is 1Ns / mm, the comparison curves of the ideal foot-end disturbance force, the foot-end disturbance force solved by FDM, and the foot-end disturbance force solved by TRM are shown as follows: Figure 4 and Figure 5 As shown in the figure, the ideal force is the given foot-end interference force; the force calculated by FDM is the foot-end interference force calculated by the method proposed in the present invention; and the force calculated by TRM is the foot-end interference force calculated without performing discrete sampling of the foot-end interference force at equal intervals.

[0146] Under the action of external disturbance force, the maximum displacement of point F of the leg of the hydraulic foot robot in the x-direction or y-direction is about 20mm, which is a large change and does not meet the microelement idea based on which the equivalent stiffness and equivalent damping mapping matrix is ​​derived. Direct comparison of the foot-end disturbance force will inevitably result in a large error. Figure 4-5 It can be seen that, whether in the x-direction or the y-direction, compared with the foot-end disturbance force calculated by the TRM method, after the foot-end disturbance force is discretized at equal intervals, the foot-end disturbance force curve calculated by the FDM method is closer to the ideal foot-end disturbance force curve, indicating that the FDM method can greatly improve the verification accuracy of the equivalent stiffness and equivalent damping mapping matrices in the robot joint space and the foot-end Cartesian space.

[0147] The present invention provides a verification method for the equivalent stiffness and equivalent damping mapping matrices in Cartesian space and joint space of an n-degree-of-freedom serial hydraulic legged robot based on a finite difference method. The method can verify the accuracy of the equivalent stiffness and equivalent damping mapping matrices, ensure the accuracy of the equivalent mapping matrices, and has wide applicability and can be applied to various hydraulic robot fields.

[0148] The embodiments described above are only descriptions of the preferred implementation modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design 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 all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for testing equivalent stiffness and equivalent damping mapping matrix of a hydraulic foot robot, characterized in that: It includes the following steps: S1, the hydraulic robot foot end interference force F L Discrete sampling is performed to obtain the change of the foot-end interference force of the hydraulic robot at adjacent moments ΔF L , the specific calculation formula is: ΔF L =F L (t i +Δt)-F L (t i ) Where Δt is the sampling interval, t i is the i-th sampling moment, ΔF L is the change of the interference force at the foot end of the hydraulic robot at adjacent moments, F L is the disturbance force at the foot end of the hydraulic robot; S2. The displacement change of the foot end of the hydraulic robot at adjacent moments is obtained by using the change of the disturbance force at the foot end of the hydraulic robot at adjacent moments and the Cartesian space impedance stiffness and impedance damping matrix of the foot end. c , the calculation formula is as follows: Among them, Z Dc is the foot end impedance characteristic parameter, Δx c is the displacement change of the foot end of the hydraulic robot at adjacent moments; S3, the displacement change of the robot foot end is solved by inverse kinematics to obtain the displacement change of the joint drive unit Δx p , the specific calculation formula is: Δx p =AJ + Δx c Among them, J + is the pseudo-inverse matrix of the robot Jacobian matrix J, A is the configuration matrix, Δx p is the displacement change of the joint drive unit; S4. Multiply the change in the output force of the joint hydraulic drive unit by the joint equivalent impedance characteristic parameter to obtain the change in the output force of the joint hydraulic drive unit at adjacent moments ΔF h , the specific calculation formula is: ΔF h =Z Dh Δx p Among them, Z Dh is the equivalent impedance characteristic parameter of the hydraulic drive unit, ΔF h is the change in output force of the joint hydraulic drive unit at adjacent moments; S5. The output force change of the robot joint hydraulic drive unit is solved by positive statics to obtain the robot foot end interference force ΔF L ', the specific calculation formula is: Among them, J T is the transposed matrix of the robot Jacobian matrix J, (J T ) + For J T The generalized inverse matrix of , L is the robot link length matrix, ΔF′ L is the disturbance force on the robot foot obtained by positive statics solution, τ′ is the torque on the revolute joint; S6. The foot-end disturbance force ΔF' obtained when the hydraulic robot performs impedance control on the joint L Accumulate and sum to get the robot's predicted foot-end interference force F' L , the specific calculation formula is: Where N is the number of discrete samples, F' L Predict the foot-end disturbance force for the robot obtained through prediction; S7, the foot end interference force F L and the predicted foot end disturbance force F' L Compare them, if the two are equal, the output equivalent impedance stiffness and equivalent impedance damping mapping matrix is ​​correct.

2. The method for testing the equivalent stiffness and equivalent damping mapping matrix of a hydraulic legged robot according to claim 1, characterized in that: The impedance characteristic parameter Z in step S2 Dc The expression is: Z Dc =B c s+K c Among them, B c is the Cartesian space damping matrix at the foot end, K c is the Cartesian space stiffness matrix of the foot end, and s is the Laplace operator.

3. The method for testing the equivalent stiffness and equivalent damping mapping matrix of a hydraulic legged robot according to claim 1, characterized in that: Impedance characteristic parameter Z Dh The expression is: Z Dh =B h s+K h Among them, B h is the equivalent damping matrix in joint space, K h is the equivalent stiffness matrix in joint space.

4. The method for testing the equivalent stiffness and equivalent damping mapping matrix of a hydraulic legged robot according to claim 1, characterized in that: In step S1, Δt is 1 ms.

5. The method for testing the equivalent stiffness and equivalent damping mapping matrix of a hydraulic legged robot according to claim 1, characterized in that: As shown in step S7, the foot end interference force F L and the predicted foot end disturbance force F L If they are not equal, the equivalent impedance stiffness and equivalent impedance damping mapping matrix is ​​re-derived and steps S1-S6 are repeated for re-verification.

6. The method for testing the equivalent stiffness and equivalent damping mapping matrix of a hydraulic legged robot according to claim 1, characterized in that: Equivalent damping matrix B of the leg joint space of hydraulic footed robot h The exact relationship between it and the foot-end Cartesian spatial damping matrix Bc is: B h =L -1 J T B c YES -1 。 7. The method for testing the equivalent stiffness and equivalent damping mapping matrix of a hydraulic legged robot according to claim 1, characterized in that: The equivalent stiffness matrix K of the leg joint space of hydraulic foot robot h The exact relationship between it and the foot-end Cartesian space stiffness matrix Kc is: K h =L -1 (J T K c J+K s -K hs )A -1 。 8. A testing system for the hydraulic legged robot equivalent stiffness and equivalent damping mapping matrix testing method according to claim 1, characterized in that: It includes a hydraulic robot foot-end interference force variation calculation unit at adjacent moments, a hydraulic robot foot-end displacement variation calculation unit at adjacent moments, a joint drive unit displacement variation calculation unit, an adjacent moment joint hydraulic drive unit output force variation calculation unit, a robot foot-end interference force calculation unit, a robot foot-end interference calculation unit, and a verification unit; The hydraulic robot foot-end interference force variation calculation unit at adjacent moments is used to discretely sample the hydraulic robot foot-end interference force to obtain the hydraulic robot foot-end interference force variation at adjacent moments; The foot end displacement variation calculation unit of the hydraulic robot at adjacent moments is used to obtain the foot end displacement variation of the hydraulic robot at adjacent moments by using the foot end interference force variation of the hydraulic robot at adjacent moments and the Cartesian space impedance stiffness and impedance damping matrix of the foot end; The joint drive unit displacement variation calculation unit is used to obtain the joint drive unit displacement variation by solving the robot foot end displacement variation through inverse kinematics; The output force variation calculation unit of the joint hydraulic drive unit at adjacent moments is used to multiply the output force variation of the joint hydraulic drive unit by the joint equivalent impedance characteristic parameter to obtain the output force variation of the joint hydraulic drive unit at adjacent moments; The robot foot-end interference force calculation unit is used to obtain the robot foot-end interference force by solving the output force variation of the robot joint hydraulic drive unit through positive statics; The robot foot-end interference unit is used to accumulate and sum the foot-end interference force obtained when the hydraulic robot performs impedance control on the joint to obtain the robot foot-end interference; The verification unit is used to compare the foot-end disturbance force with the predicted foot-end disturbance force and output the comparison result.

9. The test system according to claim 8, characterized in that: If the foot-end disturbance force is equal to the predicted foot-end disturbance force, the output equivalent impedance stiffness and equivalent impedance damping mapping matrix is ​​correct. If the foot-end disturbance force is not equal to the predicted foot-end disturbance force, the equivalent impedance stiffness and equivalent impedance damping mapping matrix is ​​re-derived and verified again.

10. A computer device used in the test system according to claim 9, characterized in that: The computer device comprises the above-mentioned hydraulic foot robot equivalent stiffness and equivalent damping mapping matrix testing system.

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