A multi-joint robot control method, system, and multi-joint robot

Abstract

The embodiment of the application discloses a kind of multi-joint robot control method, system and multi-joint robot, control method includes based on robot dynamics model establishes single joint impedance control model;Based on single joint impedance control model, the cut-off frequency of robot control system and critical damping condition determine the stiffness range of single joint;Utilize the stiffness maximum value of stiffness range and corresponding damping value of single joint;Based on dynamics model establishes multi-joint impedance control model and Cartesian impedance model;Based on multi-joint impedance control model and Cartesian impedance model, joint control law is obtained;Based on joint control law, utilize the stiffness maximum value of single joint and corresponding damping value, carry out optimal impedance control, the technical problem that precision is lower when existing technology utilizes impedance control method to carry out dynamic performance control to robot is solved, realizes the technical effect of improving the control precision of robot.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of robot control technology, and in particular to a multi-joint robot control method, system and multi-joint robot. Background Technology

[0002] Currently, position-controlled robots are the most widely used. To meet the high compliance and safety requirements of collaborative robots and service robots, force-controlled robots have gained significant attention. Force-controlled robots are more complex to control and exhibit higher nonlinearity. At present, active compliance control technology is relatively mature, with impedance / admittance control and force / position hybrid control being the most commonly used methods.

[0003] In force control algorithms, impedance control exhibits excellent compliance, making it suitable for interactive applications. Impedance control is a strategy that controls the dynamic performance of a robot by adjusting its impedance parameters, thereby improving the robot's performance and adaptability. In practical engineering, parameters often need to be continuously adjusted to achieve a usable state; therefore, determining the optimal stiffness and damping for impedance control becomes crucial for precise robot control. Summary of the Invention

[0004] This invention provides a multi-joint robot control method, system, and multi-joint robot, which solves the technical problem of low accuracy in the prior art when using impedance control method to control the dynamic performance of robots.

[0005] This invention provides a control method for a multi-joint robot, applied to a robot control system, the control method comprising:

[0006] A single-joint impedance control model is established based on the robot dynamics model. The single-joint impedance control model is used to characterize the relationship between joint angle error, moment of inertia, damping, stiffness and torque in a single joint of the robot.

[0007] The stiffness range of a single joint is determined based on the single-joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition, wherein the critical damping condition refers to a damping ratio of 1.

[0008] The maximum stiffness and corresponding damping value of a single joint are determined using the stiffness range.

[0009] Based on the aforementioned dynamic model, a multi-joint impedance control model and a Cartesian impedance model are established. The multi-joint impedance control model is used to characterize the relationship between joint angle error, moment of inertia matrix, damping matrix, stiffness matrix, and torque vector in multiple joints of the robot.

[0010] The joint control law is obtained based on the multi-joint impedance control model and the Cartesian impedance model.

[0011] Based on the joint control law, optimal impedance control is performed using the maximum stiffness of a single joint and the corresponding damping value.

[0012] Furthermore, determining the stiffness range of a single joint based on the single-joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition includes:

[0013] Based on the single-joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition, a first relationship between the cutoff frequency and damping and stiffness is determined.

[0014] The stiffness range of a single joint is determined based on the principle that the cutoff frequency is less than half of the sampling frequency and the first relationship.

[0015] Furthermore, determining the first relationship between the cutoff frequency and damping and stiffness based on the single-joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition includes:

[0016] Based on the single-joint impedance control model, and based on the cutoff frequency of the robot control system... The critical damping condition ζ = 1 determines the first relationship between the cutoff frequency and the stiffness. Among them, w b The cutoff frequency and the natural frequency are mentioned above. Damping ratio D is the damping, K is the stiffness, and M is the moment of inertia.

[0017] Furthermore, determining the stiffness range of a single joint based on the principle that the cutoff frequency is less than half of the sampling frequency and the first relationship includes:

[0018] Obtain the delay time T of the robot control system 延迟 =T;

[0019] Using T 采样 =2T sample hold instead of T 延迟 =T is a delay element;

[0020] Based on the principle that the cutoff frequency is less than half of the sampling frequency, the second relationship between the cutoff frequency and the sampling frequency is determined as follows:

[0021] The stiffness range of a single joint is determined using the second relationship and the first relationship:

[0022] Furthermore, before establishing a single-joint impedance control model based on the robot dynamics model, the control method further includes:

[0023] Establish robot dynamics model Where q represents the joint angle vector. Represents the joint angular velocity vector. M(q) represents the joint angular acceleration vector, and M(q) represents the inertia matrix. Let g(q) represent the centrifugal force matrix, g(q) represent the gravitational torque vector, and τ represent the joint torque vector. ext This represents the external torque vector.

[0024] Furthermore, establishing a single-joint impedance control model based on the robot dynamics model includes:

[0025] The single-joint impedance control model is established based on the robot dynamics model: Where i is the joint number. Indicates joint angle error. Indicates the joint angular velocity error. M represents the joint angular acceleration error, D represents the moment of inertia, and K represents the damping.

[0026] Furthermore, the establishment of a multi-joint impedance control model and a Cartesian impedance model based on the aforementioned dynamic model includes:

[0027] A multi-joint impedance control model is established based on the aforementioned dynamic model: in, This represents the joint angle error vector. This represents the joint angular velocity error vector. M represents the joint angular acceleration error vector. 矩阵 =diag(M1, ..., M) n ), D 矩阵 =diag(D1, ..., D n ), K 矩阵 =diag(K1, ..., K) n ), where n is the total number of joints;

[0028] Based on the aforementioned dynamic model, a Cartesian impedance model is established: in, Indicates the Cartesian pose error. J represents the Jacobian matrix, Λ(x) = J -T M 矩阵 (p)J -1 D(x) = J -TD 矩阵 J -1 , Let denote the derivative of the Jacobian matrix, and q denote the joint angle vector. Representing the joint angular velocity, K(x) = J -T K 矩阵 J -1 F ext F represents the Cartesian external force vector. ext =J -T τ ext .

[0029] Furthermore, the joint control law obtained based on the multi-joint impedance control model and the Cartesian impedance model includes:

[0030] Based on the aforementioned multi-joint impedance control model and the Cartesian impedance model, the joint control law is obtained: Where, x d This indicates the desired Cartesian pose.

[0031] This invention also provides a multi-joint robot control system, the control system comprising:

[0032] A single-joint model building unit is used to build a single-joint impedance control model based on the robot dynamics model. The single-joint impedance control model is used to characterize the relationship between joint angle error, moment of inertia, damping, stiffness and torque in a joint of the robot.

[0033] The first parameter determination unit is used to determine the stiffness range of a single joint based on the single joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition, wherein the critical damping condition refers to a damping ratio of 1.

[0034] The second parameter determination unit is used to determine the maximum stiffness and corresponding damping value of a single joint using the stiffness range.

[0035] The multi-joint model building unit is used to build a multi-joint impedance control model and a Cartesian impedance model based on the dynamic model. The multi-joint impedance control model is used to characterize the relationship between the joint angle error vector, rotational inertia matrix, damping matrix, stiffness matrix and corresponding torque vector in multiple joints of the robot.

[0036] A control relationship determination unit is used to obtain joint control laws based on the multi-joint impedance control model and the Cartesian impedance model.

[0037] An impedance control unit is used to perform optimal impedance control based on the joint control law, using the maximum stiffness of a single joint and the corresponding damping value.

[0038] This invention also provides a multi-joint robot, which includes the multi-joint robot control system described in any of the above embodiments.

[0039] This invention discloses a control method, system, and multi-joint robot for a multi-joint robot. The control method includes: establishing a single-joint impedance control model based on a robot dynamics model; determining the stiffness range of a single joint based on the single-joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition; determining the maximum stiffness and corresponding damping value of a single joint using the stiffness range; establishing a multi-joint impedance control model and a Cartesian impedance model based on the dynamics model; obtaining the joint control law based on the multi-joint impedance control model and the Cartesian impedance model; and performing optimal impedance control based on the joint control law, using the maximum stiffness and corresponding damping value of a single joint. This solves the technical problem of low accuracy in the prior art when using impedance control methods to control the dynamic performance of robots, and achieves the technical effect of improving the control accuracy of the robot.

[0040] This invention analyzes a second-order mass-damped stiffness system equivalent to impedance control, and determines the optimal stiffness and damping for impedance control under different operating conditions. Attached Figure Description

[0041] Figure 1 This is a flowchart of a control method for a multi-joint robot provided in an embodiment of the present invention;

[0042] Figure 2 This is a structural diagram of a multi-joint robot control system provided in an embodiment of the present invention. Detailed Implementation

[0043] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0044] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this invention are used to distinguish different objects, not to limit a specific order. The various embodiments of this invention described below can be performed individually or in combination with each other; the embodiments of this invention do not impose specific limitations in this regard.

[0045] Figure 1 This is a flowchart of a control method for a multi-joint robot provided in an embodiment of the present invention. This control method for a multi-joint robot is applied to a robot control system, such as... Figure 1As shown, the control method for this multi-joint robot specifically includes the following steps:

[0046] S101. A single-joint impedance control model is established based on the robot dynamics model. The single-joint impedance control model is used to characterize the relationship between joint angle error, moment of inertia, damping, stiffness and corresponding torque in a joint of the robot.

[0047] Optionally, before S101 establishes a single-joint impedance control model based on the robot dynamics model, the control method further includes:

[0048] Establish robot dynamics model Where q represents the joint angle vector. Represents the joint angular velocity vector. M(q) represents the joint angular acceleration vector, and M(q) represents the inertia matrix. Let g(q) represent the centrifugal force matrix, g(q) represent the gravitational torque vector, and τ represent the joint torque vector. ext This represents the external torque vector.

[0049] Optionally, S101, establishing a single-joint impedance control model based on the robot dynamics model specifically includes:

[0050] Establish a single-joint impedance control model based on the robot dynamics model: Where i is the joint number. Indicates joint angle error. Indicates the joint angular velocity error. M represents the joint angular acceleration error, D represents the moment of inertia, and K represents the damping.

[0051] S102, the stiffness range of a single joint is determined based on the single-joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition, where the critical damping condition refers to a damping ratio of 1.

[0052] Specifically, for impedance control, the system is unstable when the damping ratio is less than 0, and overshoot occurs when the damping ratio is greater than 0 but less than 1. While the system has no overshoot when the damping ratio is greater than 1, the larger the damping ratio, the slower the response. Therefore, to ensure that the system is neither unstable nor overshooted, and has a fast response, a damping ratio of 1 should be selected.

[0053] Optionally, S102, determining the stiffness range of a single joint based on the single-joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition specifically includes:

[0054] The first relationship between cutoff frequency, damping, and stiffness is determined based on the single-joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition.

[0055] The stiffness range of a single joint is determined based on the principle that the cutoff frequency is less than half of the sampling frequency and the first relationship.

[0056] Specifically, the first relationship between cutoff frequency and damping and stiffness is determined based on the single-joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition, including:

[0057] Based on the single-joint impedance control model, and considering the cutoff frequency of the robot control system... And the critical damping condition ζ=1 determines the first relationship between the cutoff frequency and damping and stiffness. Among them, w b Cutoff frequency, natural frequency Damping ratio D is damping, K is stiffness, and M is moment of inertia.

[0058] in, This is used to calculate the closed-loop cutoff frequency of the equivalent mass-damped stiffness second-order system for impedance control. Since the mass-damped stiffness second-order system (i.e., the robot control system mentioned above) is in a critically damped state when the damping ratio ζ = 1, and ζ less than 1 will cause overshoot, ζ = 1 is used as the critical damping condition, and the cutoff frequency w is used... b The calculation formula yields the first relationship between the cutoff frequency and damping / stiffness.

[0059] Specifically, the stiffness range of a single joint is determined based on the principle that the cutoff frequency is less than half of the sampling frequency and the first relationship, including:

[0060] Obtain the delay time T of the robot control system 延迟 =T; using T 采样 =2T sample hold instead of T 延迟 =T delay element; based on the principle that the cutoff frequency is less than half of the sampling frequency, the second relationship between the cutoff frequency and the sampling frequency is determined as follows: The stiffness range of a single joint is determined using the second and first relations:

[0061] For the robot control system, the transfer function of its delay element is: F 延迟 (s)=0dB∠(-360°fT 延迟 The sample-and-hold transfer function is: F S-H (s)≈0dB∠(-180°fT 采样The approximation in the above formula is almost perfectly accurate. In fact, its phase is accurate; only the gain deviates slightly at high frequencies. However, this deviation is usually negligible, only a few dB, and further analysis of the system at high frequencies to achieve better accuracy is no longer necessary. Therefore, T is used... 采样 =2T sample hold instead of T 延迟 For the delay element T, the impedance parameters are designed based on the principle that the system cutoff frequency is less than half of the sampling frequency, resulting in the second relationship between the cutoff frequency and the sampling frequency: Therefore, the stiffness range of a single joint is obtained as follows:

[0062] S103, using the stiffness range to determine the maximum stiffness of a single joint and the corresponding damping value;

[0063] Specifically, in order to maintain system stability and prevent overshoot, the damping ratio ζ needs to be 1.

[0064]

[0065]

[0066] Therefore, the maximum stiffness and the corresponding damping value are:

[0067]

[0068]

[0069] S104. Based on the dynamic model, a multi-joint impedance control model and a Cartesian impedance model are established. The multi-joint impedance control model is used to characterize the relationship between joint angle error, rotational inertia matrix, damping matrix, stiffness matrix and corresponding torque vector in multiple joints of the robot.

[0070] Optionally, S104, establishing a multi-joint impedance control model and a Cartesian impedance model based on the dynamic model specifically includes:

[0071] A multi-joint impedance control model is established based on the dynamic model: in, This represents the joint angle error vector. This represents the joint angular velocity error vector. M represents the joint angular acceleration error vector. 矩阵 =diag(M1, ..., M) n ), D 矩阵 =diag(D1, ..., D n ), K 矩阵 =diag(K1, ..., K) n), where n is the total number of joints;

[0072] Establish a Cartesian impedance model based on the dynamic model: in, Indicates the Cartesian pose error. J represents the Jacobian matrix, Λ(x) = J -T M 矩阵 (p)J -1 D(x) = J -T D 矩阵 J -1 , Let denote the derivative of the Jacobian matrix, and q denote the joint angle vector. Representing the joint angular velocity, K(x) = J -T K 矩阵 J -1 F ext F represents the Cartesian external force vector. ext =J -T τ ext .

[0073] S105, the joint control law is obtained based on the multi-joint impedance control model and the Cartesian impedance model.

[0074] Optionally, S105, the joint control law obtained based on the multi-joint impedance control model and the Cartesian impedance model specifically includes:

[0075] The joint control law is derived based on the multi-joint impedance control model and the Cartesian impedance model: Where, x d This indicates the desired Cartesian pose.

[0076] S106, based on the joint control law, utilizes the maximum stiffness of a single joint and the corresponding damping value to perform optimal impedance control.

[0077] Specifically, after obtaining the joint control law, the maximum stiffness and corresponding damping value of each joint are used to control the robot's joints to perform corresponding actions. Since the maximum stiffness and corresponding damping values ​​are determined by the robot control system under the current state, the final maximum stiffness and corresponding damping values ​​obtained based on different working conditions can optimize the impedance control performance.

[0078] This invention analyzes the second-order mass damping stiffness system equivalent to impedance control to determine the optimal stiffness and damping for impedance control under different working conditions, thereby enabling optimal impedance control of the robot. This solves the technical problem of low accuracy in the prior art when using impedance control to control the dynamic performance of robots, and achieves the technical effect of improving the control accuracy of the robot.

[0079] Figure 2 This is a structural diagram of a multi-joint robot control system provided in an embodiment of the present invention.

[0080] like Figure 2 As shown, the multi-joint robot control system specifically includes:

[0081] The single-joint model building unit 21 is used to build a single-joint impedance control model based on the robot dynamics model. The single-joint impedance control model is used to characterize the relationship between joint angle error, moment of inertia, damping, stiffness and corresponding torque in a joint of the robot.

[0082] The first parameter determination unit 22 is used to determine the stiffness range of a single joint based on the single joint impedance control model, the cutoff frequency of the robot control system and the critical damping condition, wherein the critical damping condition refers to a damping ratio of 1.

[0083] The second parameter determination unit 23 is used to determine the maximum stiffness of a single joint and the corresponding damping value using the stiffness range.

[0084] The multi-joint model building unit 24 is used to build a multi-joint impedance control model and a Cartesian impedance model based on the dynamic model. The multi-joint impedance control model is used to characterize the relationship between the joint angle error vector, rotational inertia matrix, damping matrix, stiffness matrix and corresponding torque vector in multiple joints of the robot.

[0085] The control relationship determination unit 25 is used to obtain the joint control law based on the multi-joint impedance control model and the Cartesian impedance model.

[0086] The impedance control unit 26 is used to perform optimal impedance control based on the joint control law, utilizing the maximum stiffness of a single joint and the corresponding damping value.

[0087] Optionally, the first parameter determining unit 22 includes:

[0088] The relationship determination sub-unit is used to determine the first relationship between the cutoff frequency and damping and stiffness based on the single-joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition.

[0089] The stiffness range determination sub-unit is used to determine the stiffness range of a single joint based on the principle that the cutoff frequency is less than half of the sampling frequency and the first relationship.

[0090] Optionally, the relationship determines the subunit specifically for:

[0091] Based on the single-joint impedance control model, and considering the cutoff frequency of the robot control system... And the critical damping condition ζ=1 determines the first relationship between the cutoff frequency and damping and stiffness. Among them, w b Cutoff frequency, natural frequency Damping ratio D is damping, K is stiffness, and M is moment of inertia.

[0092] Optionally, the stiffness range determination sub-element is specifically used for:

[0093] Obtain the delay time T of the robot control system 延迟 =T;

[0094] Using T 采样 =2T sample hold instead of T 延迟 =T is a delay element;

[0095] Based on the principle that the cutoff frequency is less than half of the sampling frequency, the second relationship between the cutoff frequency and the sampling frequency is determined as follows:

[0096] The stiffness range of a single joint is determined using the second and first relations:

[0097] Optionally, before the single-joint model building unit 21 builds the single-joint impedance control model based on the robot dynamics model, the control device further includes:

[0098] The dynamic model building unit is used to build the robot's dynamic model. Where q represents the joint angle vector. Represents the joint angular velocity vector. M(q) represents the joint angular acceleration vector, and M(q) represents the inertia matrix. Let g(q) represent the centrifugal force matrix, g(q) represent the gravitational torque vector, and τ represent the joint torque vector. ext This represents the external torque vector.

[0099] Optionally, the single-joint model building unit 21 is specifically used for:

[0100] Establish a single-joint impedance control model based on the robot dynamics model: Where i is the joint number. Indicates joint angle error. Indicates the joint angular velocity error. M represents the joint angular acceleration error, D represents the moment of inertia, and K represents the damping.

[0101] Optionally, the multi-joint model building unit 24 is specifically used for:

[0102] A multi-joint impedance control model is established based on the aforementioned dynamic model: in, This represents the joint angle error vector. This represents the joint angular velocity error vector. M represents the joint angular acceleration error vector. 矩阵 =diag(M1, ..., M) n ), D 矩阵 =diag(D1, ..., D n ), K 矩阵 =diag(K1, ..., K) n ), where n is the total number of joints;

[0103] Based on the aforementioned dynamic model, a Cartesian impedance model is established: in, Indicates the Cartesian pose error. J represents the Jacobian matrix, Λ(x) = J -T M 矩阵 (p)J -1 D(x) = J -T D 矩阵 J -1 , Let denote the derivative of the Jacobian matrix, and q denote the joint angle vector. Representing the joint angular velocity, K(x) = J -T K 矩阵 J -1 F ext F represents the Cartesian external force vector. ext =J -T τ ext .

[0104] Optionally, the control relationship determination unit 25 is specifically used for:

[0105] The joint control law is derived based on the multi-joint impedance control model and the Cartesian impedance model: Where, x d This indicates the desired Cartesian pose.

[0106] The multi-joint robot control system provided in the embodiments of the present invention can execute the multi-joint robot control method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0107] This invention also provides a multi-joint robot, which includes the multi-joint robot control system described in any of the above embodiments.

[0108] The multi-joint robot provided in this embodiment of the invention includes the multi-joint robot control system described in the above embodiments. Therefore, the multi-joint robot provided in this embodiment of the invention also has the beneficial effects described in the above embodiments, which will not be repeated here.

[0109] In the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0110] Finally, it should be noted that the above are merely preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A control method for a multi-joint robot, characterized in that, The control method, applied to a robot control system, includes: A single-joint impedance control model is established based on the robot dynamics model. The single-joint impedance control model is used to characterize the relationship between joint angle error, moment of inertia, damping, stiffness and corresponding torque in a joint of the robot. The stiffness range of a single joint is determined based on the single-joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition, wherein the critical damping condition refers to a damping ratio of 1. The maximum stiffness and corresponding damping value of a single joint are determined using the stiffness range. Based on the aforementioned dynamic model, a multi-joint impedance control model and a Cartesian impedance model are established. The multi-joint impedance control model is used to characterize the relationship between the joint angle error vector, rotational inertia matrix, damping matrix, stiffness matrix, and corresponding torque vector in multiple joints of the robot. The joint control law is obtained based on the multi-joint impedance control model and the Cartesian impedance model. Based on the joint control law, optimal impedance control is performed using the maximum stiffness of a single joint and the corresponding damping value. The stiffness range of a single joint is determined based on the single-joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition, including: Based on the single-joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition, a first relationship between the cutoff frequency and damping and stiffness is determined. The stiffness range of a single joint is determined based on the principle that the cutoff frequency is less than half of the sampling frequency and the first relationship. The first relationship between the cutoff frequency and damping and stiffness is determined based on the single-joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition, including: Based on the single-joint impedance control model, and based on the cutoff frequency of the robot control system... The critical damping condition ζ=1 determines the first relationship between the cutoff frequency and the stiffness. ,in, w b The cutoff frequency and the natural frequency are mentioned above. Damping ratio , D For the damping, K For the stiffness, M It is the moment of inertia; Based on the principle that the cutoff frequency is less than half of the sampling frequency and the first relationship, the stiffness range of a single joint is determined as follows: Obtain the delay time of the robot control system T 延迟 = T ; use T 采样 =2 T Sampling hold instead T 延迟 =T delay element; Based on the principle that the cutoff frequency is less than half of the sampling frequency, the second relationship between the cutoff frequency and the sampling frequency is determined as follows: w b ≥ ; The stiffness range of a single joint is determined using the second relationship and the first relationship: .

2. The control method for a multi-joint robot according to claim 1, characterized in that, Before establishing a single-joint impedance control model based on the robot dynamics model, the control method further includes: Establish robot dynamics model ,in, q Represents the joint angle vector. Represents the joint angular velocity vector. This represents the joint angular acceleration vector. M ( q ) represents the inertia matrix. C ( q , ) represents the centrifugal force matrix, g( q ) represents the gravitational torque vector. τ Represents the joint torque vector. τ ext This represents the external torque vector.

3. The control method for a multi-joint robot according to claim 2, characterized in that, The single-joint impedance control model based on the robot dynamics model includes: The single-joint impedance control model is established based on the robot dynamics model: Where i is the joint number. Indicates joint angle error. Indicates the joint angular velocity error. This indicates the joint angular acceleration error. M Represents the moment of inertia. D Indicates damping, K Indicates stiffness.

4. The control method for a multi-joint robot according to claim 3, characterized in that, Based on the aforementioned dynamic model, a multi-joint impedance control model and a Cartesian impedance model are established, including: A multi-joint impedance control model is established based on the aforementioned dynamic model: ,in, This represents the joint angle error vector. This represents the joint angular velocity error vector. This represents the joint angular acceleration error vector. M 矩阵 =diag( M 1, ..., M n ), D 矩阵 =diag( D 1, ..., D n ), K 矩阵 =diag( K 1, ..., K n ), where n is the total number of joints; Based on the aforementioned dynamic model, a Cartesian impedance model is established: ,in, Indicates the Cartesian pose error. , J Denotes the Jacobian matrix, Λ( x )= J -T M 矩阵 ( p ) J -1 , D ( x )= J -T D 矩阵 J -1 , , The derivative of the Jacobian matrix is ​​expressed as... Represents the joint angle vector. Indicates joint angular velocity, K ( x )= J -T K 矩阵 J -1 , F ext Denotes the Cartesian external force vector. F ext = J -T τ ext .

5. The control method for a multi-joint robot according to claim 4, characterized in that, Based on the multi-joint impedance control model and the Cartesian impedance model, the joint control laws include: Based on the aforementioned multi-joint impedance control model and the Cartesian impedance model, the joint control law is obtained: ,in, x d This indicates the desired Cartesian pose.

6. A multi-joint robot control system, characterized in that, The control system includes: A single-joint model building unit is used to build a single-joint impedance control model based on the robot dynamics model. The single-joint impedance control model is used to characterize the relationship between joint angle error, moment of inertia, damping, stiffness and torque in a joint of the robot. The first parameter determination unit is used to determine the stiffness range of a single joint based on the single joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition, wherein the critical damping condition refers to a damping ratio of 1. The second parameter determination unit is used to determine the maximum stiffness and corresponding damping value of a single joint using the stiffness range. The multi-joint model building unit is used to build a multi-joint impedance control model and a Cartesian impedance model based on the dynamic model. The multi-joint impedance control model is used to characterize the relationship between the joint angle error vector, rotational inertia matrix, damping matrix, stiffness matrix and torque vector in multiple joints of the robot. A control relationship determination unit is used to obtain joint control laws based on the multi-joint impedance control model and the Cartesian impedance model. An impedance control unit is used to perform optimal impedance control based on the joint control law, using the maximum stiffness of a single joint and the corresponding damping value. The first parameter determination unit includes: The relationship determination subunit is used to determine the first relationship between the cutoff frequency and damping and stiffness based on the single-joint impedance control model, the cutoff frequency of the robot control system, and the critical damping condition. A stiffness range determination sub-unit is used to determine the stiffness range of a single joint based on the principle that the cutoff frequency is less than half of the sampling frequency and the first relationship. The relationship-determining subunit is specifically used for: Based on the single-joint impedance control model, and based on the cutoff frequency of the robot control system... The critical damping condition ζ=1 determines the first relationship between the cutoff frequency and damping and stiffness. ,in, w b The cutoff frequency and the natural frequency are mentioned above. Damping ratio , D For the damping, K For the stiffness, M It is the moment of inertia; The stiffness range determination sub-unit is specifically used for: Obtain the delay time of the robot control system T 延迟 = T ; use T 采样 =2 T Sampling hold instead T 延迟 =T delay element; Based on the principle that the cutoff frequency is less than half of the sampling frequency, the second relationship between the cutoff frequency and the sampling frequency is determined as follows: w b ≥ ; The stiffness range of a single joint is determined using the second relationship and the first relationship: .

7. A multi-joint robot, characterized in that, The multi-joint robot includes the multi-joint robot control system described in claim 6.

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