Testing method of equivalent stiffness and equivalent damping mapping matrix for hydraulic legged robot

Abstract

The present invention relates to a method for testing equivalent stiffness and equivalent damping mapping matrices of a hydraulic footed robot, which belongs to the field of robot control and simulation technology. The method comprises: S1: testing the hydraulic robot foot end interference force F L Discrete sampling is performed to obtain the change in the robot foot-end interference force at adjacent moments; S2 obtains the change in the foot-end displacement of the hydraulic robot at adjacent moments; S3 calculates the change in the displacement of the joint drive unit; S4 obtains the change in the output force of the joint hydraulic drive unit of the hydraulic robot at adjacent moments; S5 obtains the change in the hydraulic robot foot-end force by positive statics solution of the change in the output force of the joint hydraulic drive unit; S6 accumulates and sums the foot-end force changes to obtain the foot-end interference force F L '; S7 will foot end interference force F L and foot-end interference force F L 'Compare and judge whether the equivalent impedance stiffness and equivalent impedance damping mapping matrices are correct. It can verify the accuracy of the equivalent stiffness and equivalent damping mapping matrices and ensure the accuracy of the equivalent mapping matrix.

Description

Technical Field

[0001] The present 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 footed robot. Background Art

[0002] Compared to other types of robots, such as wheeled and tracked robots, legged robots can achieve discontinuous support and are more adaptable to unknown environments. In particular, when combined with hydraulic systems with a high power-to-weight ratio, they can significantly increase their load-bearing capacity, making them more suitable for field operations and heavy-load transportation. This has become a hot research area in various countries. However, during the movement of hydraulic legged robots, impact between the foot and the ground is inevitable, so compliant control is required to reduce the impact force generated by contact with the environment.

[0003] Compared to passive compliance control, active compliance control uses algorithms to simulate passive spring-damper systems, offering greater environmental adaptability and adjustability. Impedance control is a common active compliance control method widely used in the compliance control of hydraulic legged robots. Currently, common impedance control methods are performed in the Cartesian space of the foot end. By simulating the stiffness and damping system at the foot end, compliance can be achieved in the foot end space. However, implementing impedance control at the foot end presents two challenges: first, the kinematic, static, and dynamic solutions affect the response speed of the compliance control; second, it hinders the selection of the inner loop of the 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 and damping system there.

[0004] However, the derivation of the equivalent impedance stiffness and equivalent impedance damping mapping matrices in both Cartesian and joint space is based on the concept of microelement. This means that the equivalent mapping matrices are more suitable for hydraulic robots with small foot displacements. However, in most cases, the robot's foot displacement is large, which results in significant errors during the verification of the equivalent mapping matrices, affecting their accuracy. Therefore, a high-precision verification method for the equivalent impedance stiffness and equivalent impedance damping mapping matrices for serial hydraulic legged robots is urgently needed. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a verification method for the equivalent stiffness and equivalent damping mapping matrices in the 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 objectives, the present invention discloses the following technical solutions:

[0007] Specifically, on 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 Perform discrete sampling to obtain the change in the foot-end interference force of the hydraulic robot at adjacent moments ΔF L , and 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 in the foot-end interference force of the hydraulic robot at adjacent moments, F L is the disturbance force at the foot end of the hydraulic robot;

[0011] S2. Use the foot-end interference force change at adjacent moments of the hydraulic robot and the Cartesian space impedance stiffness and impedance damping matrix of the foot-end to obtain the foot-end displacement change Δx of the hydraulic robot at adjacent moments 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 , and 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 joint hydraulic drive unit output force change by the joint equivalent impedance characteristic parameter to obtain the joint hydraulic drive unit output force change ΔF at adjacent moments. h , and 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 is the change in output force of the joint hydraulic drive unit at adjacent moments.

[0020] S5. The output force variation of the hydraulic drive unit of the robot joint is solved by positive statics to obtain the robot foot end interference force ΔF′ L , and 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 the positive statics solution, and 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 Accumulate and sum to get the robot's predicted foot-end interference force F′ L , and 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 joint space equivalent damping matrix, 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 hydraulic leg robot leg joint space 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 JA -1 .

[0037] Preferably, the equivalent stiffness matrix K of the leg joint space of the hydraulic footed 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 an equivalent stiffness and equivalent damping mapping matrix testing system for a hydraulic legged robot, 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 output force variation calculation unit 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;

[0040] The hydraulic robot foot-end interference force variation calculation unit 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 hydraulic robot foot end displacement variation calculation unit at adjacent moments is used to obtain the hydraulic robot foot end displacement variation at adjacent moments by using the hydraulic robot foot end interference force variation at adjacent moments and the foot end Cartesian space impedance stiffness and impedance damping matrix;

[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 interference force with the predicted foot-end interference 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 further provides a computer device, which includes 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 method for verifying the equivalent stiffness and equivalent damping mapping matrices in the 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 legged 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 according to the present invention;

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

[0056] Figure 4 2. It 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 Schematic diagram comparing the interference force at the foot end in the y direction of the hydraulic robot of the present invention.

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

[0059] O is the knee joint, D is the ankle joint, θ1 is the knee joint rotation angle, θ2 is the ankle joint rotation angle, τ1 is the knee joint torque, τ2 is the ankle joint torque, 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 indicated.

[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 interference 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 in the foot-end interference force 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 foot-end interference force change by the foot-end impedance characteristic parameter to obtain the foot-end displacement change 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 , and 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 , and 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 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 joint space equivalent damping matrix, K h is the equivalent stiffness matrix in joint space.

[0080] S5: The force variation of the hydraulic drive unit output of the joint is obtained by the statics forward solution to obtain the force variation of the hydraulic robot foot end 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 the 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 Accumulate and sum to get the robot's predicted foot-end interference force F′ L , and the relationship is:

[0084]

[0085] Where N is the number of discrete samples, F′ L is the robot foot-end interference force obtained through calculation.

[0086] S7: The foot end interference force FL and foot-end interference force F′ L Compare them. 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 foot-end interference force change calculation unit for a hydraulic robot at adjacent moments, a foot-end displacement change calculation unit for a hydraulic robot at adjacent moments, a joint drive unit displacement change calculation unit, an output force change calculation unit for 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 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.

[0089] The hydraulic robot's foot end displacement change calculation unit at adjacent moments is used to obtain the hydraulic robot's foot end displacement change at adjacent moments by using the hydraulic robot's foot end interference force change 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 interference force calculation unit is used to obtain the robot foot-end interference force by solving the output force change 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 joint to obtain the robot foot-end interference.

[0094] The verification unit is used to compare the foot-end interference force with the predicted foot-end interference 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 for a testing system of a hydraulic legged robot equivalent stiffness and equivalent damping mapping matrix testing method, and the computer device includes the above-mentioned hydraulic legged robot equivalent stiffness and equivalent damping mapping matrix testing 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 to detect the equivalent stiffness and equivalent damping mapping matrix of a hydraulic legged robot. First, a schematic diagram of the serial hydraulic legged single leg structure is established, as shown in FIG. 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 vertically 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. 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 each joint hydraulic drive unit. Figure 3 The values ​​of the structural parameters of the middle leg are shown in Table 1:

[0099] Table 1 Mechanical structure parameter values ​​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 end 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 inverse solution of the robot's statics is:

[0112]

[0113] Where 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 hydraulic drive unit of the knee joint, △F s2 The force is applied to the ankle joint hydraulic drive unit.

[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 in are as follows:

[0122]

[0123] For the knee joint of the hydraulic leg 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 footed 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 as 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 JA -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 interference force of 2000sin(2πt)N is applied in the x-direction of point F of the hydraulic footed robot leg, a sinusoidal interference 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 interference force, the foot-end interference force solved by FDM, and the foot-end interference 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 using FDM is the foot-end interference force calculated using the method proposed in this invention; and the force calculated using TRM is the foot-end interference force calculated without performing equally spaced discrete sampling on the foot-end interference force.

[0146] Under the action of external interference force, the maximum displacement of point F of the hydraulic foot robot leg in the x-direction or y-direction is about 20mm, which is a large variation and does not meet the infinitesimal idea based on which the equivalent stiffness and equivalent damping mapping matrix is ​​derived. Direct comparison of the foot-end interference force will inevitably result in a large error. Figures 4 and 5 It can be seen from the figure 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 matrix of 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 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 wide applicability and can be applied to various hydraulic robot fields.

[0148] The embodiments described above 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 method for testing equivalent stiffness and equivalent damping mapping matrices of a hydraulic legged robot, characterized by: It includes the following steps: S1, the hydraulic robot foot end interference force Perform discrete sampling to obtain the change in the foot-end interference force of the hydraulic robot at adjacent moments , the specific calculation formula is: ； in, is the sampling interval, For the Sampling time, is the change in the interference force at the foot end of the hydraulic robot at adjacent moments, is the disturbance force at the foot end of the hydraulic robot; S2. Use the foot-end interference force change of the hydraulic robot at adjacent moments and the Cartesian space impedance stiffness and impedance damping matrix of the foot-end to obtain the foot-end displacement change of the hydraulic robot at adjacent moments , the calculation formula is as follows: ； in, is the foot end impedance characteristic parameter, is the displacement change of the foot end of the hydraulic robot at adjacent moments; Foot end impedance characteristic parameters The expression is: ； in, is the Cartesian space damping matrix at the foot end, is the Cartesian space stiffness matrix of the foot end, is the Laplace operator; S3. The displacement change of the robot foot end is calculated by inverse kinematics to obtain the displacement change of the joint drive unit. , the specific calculation formula is: ； in, is the robot Jacobian matrix J The pseudo-inverse matrix of A is the configuration matrix, is the displacement change of the joint drive unit; S4. Multiply the output force change of the joint hydraulic drive unit by the joint equivalent impedance characteristic parameter to obtain the output force change of the joint hydraulic drive unit at adjacent moments. , the specific calculation formula is: ； in, is the equivalent impedance characteristic parameter of the hydraulic drive unit, is the change in output force of the joint hydraulic drive unit at adjacent moments; Equivalent impedance characteristic parameters of hydraulic drive unit The expression is: ； in, is the equivalent damping matrix in joint space, is the equivalent stiffness matrix of the joint space; S5. The output force change of the hydraulic drive unit of the robot joint is solved by positive statics to obtain the interference force at the robot foot end. , the specific calculation formula is: ； in, is the robot Jacobian matrix J The transposed matrix of for The generalized inverse matrix of L is the robot link length matrix, is the disturbance force at the robot foot obtained by solving the positive statics, is the torque acting on the revolute joint; S6. The foot-end interference force obtained when the hydraulic robot performs impedance control on the joint Accumulate and sum to get the robot's predicted foot-end interference force , the specific calculation formula is: ； in, N is the discrete sampling number, Predict the foot-end disturbance force for the robot obtained through prediction; S7, the foot end interference force and predicted foot-end interference force 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: In step S1 1ms.

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: As shown in step S7, the foot end interference force and predicted foot-end interference force 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.

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: Equivalent damping matrix of the leg joint space of a hydraulic legged robot B h and the foot-end Cartesian space damping matrix Bc The exact relationship between them is: 。 5. The method for testing equivalent stiffness and equivalent damping mapping matrices of a hydraulic legged robot according to claim 1, wherein: Equivalent stiffness matrix of the leg joint of a hydraulic legged robot K h and the foot-end Cartesian space stiffness matrix Kc The exact relationship between them is: 。 6. 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 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 hydraulic robot foot end displacement variation calculation unit at adjacent moments is used to obtain the hydraulic robot foot end displacement variation at adjacent moments by using the hydraulic robot foot end interference force variation at adjacent moments and the foot end Cartesian space impedance stiffness and impedance damping matrix; 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 interference force with the predicted foot-end interference force and output the comparison result.

7. The test system according to claim 6, wherein: 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.

8. A computer device used in the test system according to claim 7, characterized in that: The computer device includes the above-mentioned hydraulic legged robot equivalent stiffness and equivalent damping mapping matrix testing system.

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