Robot compliance control method and compliance control system

Abstract

The invention provides a compliance control method and compliance control system for a robot, and the method comprises the steps: dividing a secondary term of a velocity vector into two different inputs according to a Newton-Euler method, obtaining a recursive expression of the robot, and obtaining a kinetic equation of the robot according to the recursive expression; constructing a generalized momentum observer; external force is applied in the running process of the robot, the output of the generalized momentum observer is obtained, and the external torque in physical interaction between the robot and the outside is estimated according to the output; and generating a reference position signal according to the external torque and the impedance control model, and performing compliant control on the robot according to the reference position signal. The external force generated in the interaction process of the robot and the outside world is deduced by constructing the accurate robot dynamic model and combining with the generalized momentum observer, dependence on a physical force sensor is not needed, the hardware cost is remarkably reduced, the design and maintenance process of the system is simplified, and the reliability and maintainability of the system are improved.

Description

Technical Field

[0001] The present invention relates to the field of automatic control technology, and in particular to a robot compliance control method and a robot compliance control system. Background Art

[0002] At present, robot teaching and operation imitation methods usually rely on force sensors to perceive the force exerted by the external environment in real time, so as to achieve precise control of the robot.

[0003] However, the high cost, complicated installation process and susceptibility to environmental interference of force sensors limit their widespread application in industrial and service robotics. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a robot compliance control method and a robot compliance control system.

[0005] The technical solution adopted by the present invention is as follows:

[0006] The first aspect of the present invention proposes a compliant control method for a robot, comprising the following steps: using the DH parameter method to construct a link coordinate system of the robot; according to the Newton-Euler method, splitting the secondary term of the velocity vector into two different inputs, obtaining the angular velocity and acceleration of each link of the robot and the recursive expression of the linear acceleration of the origin and center of mass of the coordinate system, and obtaining the dynamic equation of the robot according to the recursive expression; constructing a generalized momentum observer based on generalized momentum; applying external force during the operation of the robot, obtaining the output of the generalized momentum observer according to the dynamic equation and the robot operation data, and estimating the external torque in the physical interaction between the robot and the outside world according to the output of the generalized momentum observer; obtaining an impedance control model, generating a reference position signal according to the external torque and the impedance control model, and performing compliant control of the robot according to the reference position signal.

[0007] The above-mentioned robot compliance control method of the present invention also has the following additional technical features:

[0008] According to one embodiment of the present invention, the recursive expression is obtained according to the following formula:

[0009]

[0010] in, represents the angular velocity of joint i, represents the auxiliary angular acceleration of joint i, ω i is the angular velocity of connecting rod i, is the auxiliary angular velocity of connecting rod i, represents the linear acceleration of the origin of the i-link coordinate system; represents the linear acceleration at the mass center of the i-link; r i-1,i represents the vector from the i-1th joint to the i-th joint. represents the vector from the i-th joint to the center of mass of the link, ω i represents the angular velocity of connecting rod i, represents the angular acceleration of connecting rod i, represents the auxiliary angular velocity of link i, τ i represents the moment at joint i, f i represents the force at joint i, f i+1 represents the force at the i+1 joint, I i represents the inertia matrix of the i link, z i Represents the vector along the i-axis, [0 0 1] T , τ d Represents the driving torque of the robot.

[0011] According to one embodiment of the present invention, the dynamic equation of the robot is obtained according to the following formula: Where q represents the joint angle, represents the joint angular velocity, represents the joint angular acceleration, M(q) represents the inertia tensor, represents the centrifugal force and Coriolis moment term, G(q) represents the gravity vector, τ d represents the driving torque; τ e Represents the external input force mapped to the torque of each joint.

[0012] According to one embodiment of the present invention, the generalized momentum is obtained according to the following formula: Where p represents generalized momentum, M(q) represents the inertia tensor, and q represents the joint angle. Represents the joint angular velocity.

[0013] According to one embodiment of the present invention, a generalized momentum observer is constructed according to the following formula: Where r(t) represents the output of the generalized momentum observer, K represents the observer gain coefficient, for The transposed matrix of represents the centrifugal force, the Coriolis moment term G(q) represents the gravity vector, and p represents the generalized momentum.

[0014] According to one embodiment of the present invention, the impedance control model is obtained according to the following formula: Among them, M d represents the simulated mass matrix, D d represents the damping matrix, K d represents the stiffness matrix, q d ,q rRepresent the reference position and actual position of the robot, τ e Indicates the external input force mapped to the torque of each joint, Represents the joint angle of the robot when it is actually running, Represents the joint angular velocity of the robot during actual operation.

[0015] According to one embodiment of the present invention, the robot is a six-degree-of-freedom robot.

[0016] The second aspect of the present invention proposes a compliant control system of a robot, comprising: a first building module, the first building module is used to construct the robot's connecting rod coordinate system using the DH parameter method; an acquisition module, according to the Newton-Euler method, splits the secondary term of the velocity vector into two different inputs, and obtains the angular velocity and acceleration of each connecting rod of the robot and the recursive expression of the linear acceleration of the origin and center of mass of the coordinate system; a second building module, the second building module is used to establish the robot's dynamic equation according to the driving torque of the robot and the external torque in the physical interaction between the robot and the outside world; a third building module, the third building module is used to obtain the robot's centrifugal force and Coriolis moment terms according to the recursive expression Gravity vector G(q), based on generalized momentum p, centrifugal force, and Coriolis moment terms and a gravity vector G(q) to construct a generalized momentum observer; an estimation module, the estimation module is used to apply an external force during the operation of the robot, obtain the driving torque of the robot according to the current information of the robot, input the driving torque into the generalized momentum observer, and estimate the external torque in the physical interaction between the robot and the outside world according to the output of the generalized momentum observer; a control module, the control module is used to obtain an impedance control model, generate a reference position signal according to the external torque and the impedance control model, and perform compliant control of the robot according to the reference position signal.

[0017] Beneficial effects of the present invention:

[0018] The present invention constructs an accurate robot dynamics model and combines it with a generalized momentum observer to infer the external forces generated during the interaction between the robot and the outside world without relying on physical force sensors. This model-based force estimation technology not only significantly reduces hardware costs, but also simplifies the system design and maintenance process, and improves the reliability and maintainability of the system.

[0019] The present invention adopts an improved Newton-Euler method when obtaining the dynamic equation, and splits the secondary term of the velocity vector into two different inputs, so that it can be applied to robots with more degrees of freedom. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a flow chart of a compliant control method of a robot according to an embodiment of the present invention;

[0021] Figure 2 is a derivation principle diagram of a recursive expression according to an embodiment of the present invention;

[0022] Figure 3 is a block diagram of a generalized momentum observer according to an embodiment of the present invention;

[0023] Figure 4 is a block diagram of a control process of a robot according to an embodiment of the present invention;

[0024] Figure 5 is a block diagram of a compliant control system of a robot according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0026] In the framework of human-robot collaborative technology, the robot's external force perception occupies a pivotal position. Rapidly and accurately capturing external forces not only helps to improve the robot's compliance, but also optimizes the performance of the controller through a feedforward mechanism, thereby enhancing the robot's anti-interference ability in compliant control. In addition to relying on an accurate dynamic model as a cornerstone, the design of the external force observer is a key factor that directly affects the effect of external force detection.

[0027] The robot in the present invention may be a six-degree-of-freedom robot.

[0028] Figure 1 is a flow chart of a compliant control method of a robot according to an embodiment of the present invention. Figure 1 As shown, the method comprises the following steps:

[0029] S1, the DH parameter method is used to construct the robot's link coordinate system.

[0030] Specifically, the present invention takes a six-degree-of-freedom industrial robot as the research object, adopts the DH (Denavit-Hartenberg) parameter method to construct a connecting rod coordinate system, and defines its connecting rod length, torsion angle, offset and joint angle by analyzing each joint of the six-degree-of-freedom industrial robot to form an accurate connecting rod coordinate system. The DH parameter method allows for more flexible processing of the relative position relationship between joints and connecting rods, and is particularly suitable for the unique structural characteristics of six-degree-of-freedom industrial robots.

[0031] S2, according to the Newton-Euler method, split the secondary term of the velocity vector into two different inputs to obtain the recursive expressions of the angular velocity and acceleration of each link of the robot and the linear acceleration of the origin and center of mass of the coordinate system.

[0032] Specifically, the Newton-Euler method uses the principles of particle dynamics and rotational dynamics to establish the overall dynamic equation by gradually analyzing each joint and link of the robot.

[0033] First, the joint state variables of the six-degree-of-freedom industrial robot are initialized, including the position, velocity, and acceleration of the joints. The forward process starts from the root joint and calculates the linear velocity and angular velocity of each joint. The linear velocity is derived from the known joint angle and angular velocity using the connection relationship between the joints. Then, the linear acceleration and angular acceleration of each joint are calculated. By deriving the linear velocity and angular velocity, the joint motion is accurately reflected. After obtaining the linear acceleration and angular acceleration, the mass and inertia matrix of the joint are used to calculate the linear force and torque of each joint. The key variables required include the mass, center of gravity position, and inertial characteristics of the joint. The reverse process starts from the end effector, calculates the reaction force and reaction torque of each joint, and transmits the linear force and torque results of each joint to the previous joint to update the state of the previous joint. This step is achieved through a recursive relationship to ensure that the dynamic information between the front and rear joints is transmitted. For each joint, the linear velocity and angular velocity are updated using its force conditions to ensure that the state of the entire system remains consistent.

[0034] The Newton-Euler algorithm is: τ is the joint torque, g is the acceleration due to gravity, represents the joint angular velocity, represents the joint angular acceleration, NE * is the Newton-Euler algorithm;

[0035] like Figure 2 As shown, the present invention reconstructs the Newton-Euler method, and the Newton-Euler method can be concisely described as a method with 5 inputs, namely , the 4-vector function is the auxiliary angular velocity of the joint.

[0036] By adding the velocity vector The second term of is split into two different inputs, and auxiliary It can be applied to more degrees of freedom, with the additional condition that: have:

[0037]

[0038] In addition, the equation needs to satisfy the skew symmetry property, and when the algorithm NE * Call When and g = 0, g represents the gravity term, which should yield: represents the Coriolis force term;

[0039] matrix The i-th column of is: And must meet: For the matrix The elements in .

[0040] Considering the above requirements, the auxiliary angular velocity of connecting rod i is introduced It depends By recursive relation: z i-1 Represents the vector along the (i-1) axis, which is [0 0 1] T .

[0041] In addition, the following terms in the standard Newton-Euler recursion method for quadratic dependence of velocity are modified:

[0042] In the standard Newton-Euler recursion method, the angular velocity and acceleration of each link, as well as the linear acceleration of the origin and center of mass of the coordinate system are given by:

[0043]

[0044]

[0045] Among them, r represents the position vector, which is used to describe the position relationship between two points. r i-1,i =O i -O i-1 , B i and O i are the origin of the i-th reference frame and the center of mass of the i-th link, ω i represents the angular velocity of connecting rod i, represents the angular acceleration of link i, τ i represents the moment at joint i, f i represents the force at joint i, f i+1 represents the force at the i+1 joint, I i represents the inertia matrix of the i link, z i Represents the vector along the i-axis direction, which is [0 0 1] T .

[0046] In the positive recursion ω i ×(ω i × i-1,i ), and ω i ×(I i ω i ) to make modifications.

[0047] In equation (1), Multiply by ω i-1 , it is There are vector products in the remaining equations. One of the factors depends on The other depends on In all four cases above, the results will vary depending on the order of substitution. In fact, the modified expression (1) is:

[0048] Due to the antisymmetric nature of the vector product, there is a sign reversal in the torque expression, which is expressed as m×n=-(m×n), where m and n are vectors. The recursive equation for angular acceleration can be replaced by equation (1) as follows:

[0049] From the above, in one embodiment of the present invention, the recursive expression is obtained according to the following formula:

[0050]

[0051] in, represents the angular velocity of joint i, represents the auxiliary angular acceleration of joint i, ω i is the angular velocity of connecting rod i, is the auxiliary angular velocity of connecting rod i, represents the linear acceleration of the origin of the i-link coordinate system; represents the linear acceleration at the mass center of the i-link; r i-1,i represents the vector from the i-1th joint to the i-th joint. represents the vector from the i-th joint to the center of mass of the link, ω i represents the angular velocity of connecting rod i, represents the angular acceleration of connecting rod i, represents the auxiliary angular velocity of link i, τ i represents the moment at joint i, f i represents the force at joint i, f i+1 represents the force at the i+1 joint, I i represents the inertia matrix of the i link, z i Represents the vector along the i-axis direction, which is [0 0 1] T ,u i It indicates the force distance in the z direction required for the robot to move at a given speed and acceleration.

[0052] Therefore, a modified recursive Newton-Euler algorithm It can be expressed by the above recursive expression.

[0053] S3, establish the dynamic equation of the robot according to the driving torque of the robot and the external torque in the physical interaction between the robot and the outside world.

[0054] Specifically, considering the force interaction between a robot with 6 degrees of freedom and the external environment in an actual scenario, in one embodiment of the present invention, the dynamic equation is rewritten as:

[0055]

[0056] Among them, q represents the joint angle, represents the joint angular velocity, represents the joint angular acceleration, M(q) represents the inertia tensor, represents the centrifugal force and Coriolis moment term, G(q) represents the gravity vector, τ d Represents the driving torque, which is divided into two parts, one part is acted upon by external force, and the other part drives the body to move; τ e Represents the external torque in the physical interaction between the robot and the outside world, that is, the external input force is mapped to the torque of each joint, τ e =J T F ext , J represents the Jacobian matrix, F ext Represents the contact force in the physical interaction between the robot and the outside world.

[0057] τ d By obtaining the servo motor current during the operation of the robot, the external torque τ can be obtained. e It is obtained using the following generalized momentum observer.

[0058] S4, obtain the centrifugal force and Coriolis moment of the robot according to the recursive expression Gravity vector G(q), based on generalized momentum p, centrifugal force, and Coriolis moment terms And the gravity vector G(q) are used to construct a generalized momentum observer.

[0059] In order to avoid the problem of numerical differentiation of the inertia tensor M(q) or the calculation of partial derivatives of each element, the residual expression of the generalized momentum observer needs to calculate a quadratic velocity term, which is in the form of The present invention applies the above-mentioned modified Newton-Euler method to the generalized momentum observer studied in this paper, so as to simplify the inertia items in the dynamic expression.

[0060] According to one embodiment of the present invention, Figure 3 As shown, using the robot dynamics equation, the generalized momentum p is defined as: Where p represents generalized momentum, M(q) represents the inertia tensor, and q represents the joint angle. Represents the joint angular velocity.

[0061] The antisymmetric characteristics of the dynamics, that is, through the dynamic analysis of the Lagrangian form, we can get By taking the derivative of both sides of the above formula, we can get the dynamic equation without angular acceleration:

[0062] Then the estimated value of the generalized momentum derivative is for:

[0063] Define the residual r(t). The residual r(t) reflects the deviation between the model and the actual situation. This deviation is usually caused by the contact between the robot and the outside world. Therefore, this residual can be regarded as the external torque τ that needs to be observed. e , that is, the residual of the joint torque is generated by the external force. In a specific embodiment of the present invention, a generalized momentum observer is constructed according to the following formula:

[0064]

[0065] Where r(t) represents the output of the generalized momentum observer, K represents the observer gain coefficient, for The transposed matrix of represents the centrifugal force, the Coriolis moment term G(q) represents the gravity vector, and p represents the generalized momentum.

[0066] The present invention adopts a modified recursive Newton-Euler algorithm, that is, the above recursive expression The inertia items in the calculation dynamics expression are as follows:

[0067] according to Calculate the gravity vector G(q);

[0068] according to Calculate centrifugal force and Coriolis moment terms

[0069] From the above derivation process and momentum observer, we know that the deviation of and will lead to the deviation of and. After Laplace transformation, the transfer function of the residual and external torque is obtained as: r(s) = Kτ e (s)[s+K] -1 , s is the Laplace operator, and K is the gain coefficient. As can be seen from the above formula, when the gain coefficient K approaches infinity, the value will be infinitely close to the actual external torque. Therefore, the external torque can be calculated based on the output of the momentum observer.

[0070] S5, applying external force during the operation of the robot, obtaining the driving torque according to the current information of the robot, inputting the driving torque into the generalized momentum observer, and estimating the external torque in the physical interaction between the robot and the outside world according to the output of the generalized momentum observer.

[0071] Specifically, the generalized momentum observer is written into the robot's control system, and an external force is applied during the robot's operation. Based on the current information during the robot's operation, the robot's driving torque τ can be obtained. d , the driving torque τ of the robot will be obtained d The generalized momentum observer is input. According to the output of the generalized momentum observer, the external torque τ in the physical interaction between the robot and the outside world can be calculated by using the transfer function of the residual and the external torque. e .

[0072] S6, obtaining an impedance control model, generating a reference position signal according to the external torque and the impedance control model, and performing compliant control of the robot according to the reference position signal.

[0073] According to one embodiment of the present invention, the impedance control model is obtained according to the following formula:

[0074]

[0075] Among them, M d represents the mass matrix of the simulation, D d represents the damping matrix, K d represents the stiffness matrix, q d ,q r Represent the reference position and actual position of the robot, τ e represents the external torque, Represents the joint angle of the robot when it is actually running, Represents the joint angular velocity of the robot during actual operation.

[0076] Specifically, Figure 4 As shown, the output of the generalized momentum observer can be substituted into the external torque τ in the external physical interaction in the impedance control model. e , generating the robot’s reference position q d ,This signal is transmitted to the six-degree-of-freedom industrial robot through the robot controller, causing it to perform the corresponding movement.

[0077] Therefore, by using the dynamic model and observer to estimate the external torque force, it can effectively support the robot to achieve kinesthetic teaching and imitation operation when performing operation tasks. This innovative method can still accurately perceive external forces and perform complex tasks without force sensors, showing stronger robustness and adaptability, thereby significantly improving the robot's operational performance and wide application in changeable and complex environments, and laying a solid foundation for the further development of robotics technology.

[0078] In summary, the compliant control method of the robot according to the embodiment of the present invention constructs an accurate robot dynamics model and combines a generalized momentum observer to infer the external force generated during the interaction between the robot and the outside world without relying on physical force sensors. This model-based force estimation technology not only significantly reduces hardware costs, but also simplifies the design and maintenance process of the system, and improves the reliability and maintainability of the system. The present invention adopts an improved Newton-Euler method when obtaining the dynamics equation, splitting the secondary term of the velocity vector into two different inputs, so that it can be applied to robots with more degrees of freedom.

[0079] Corresponding to the above-mentioned robot compliance control method, the present invention also provides a robot compliance control system. Since the system embodiment of the present invention corresponds to the above-mentioned method embodiment, details not disclosed in the system embodiment can be referred to the above-mentioned method embodiment, and the present invention will not repeat them.

[0080] Figure 5 is a block diagram of a compliant control system of a robot according to an embodiment of the present invention, as shown in Figure 5 As shown, the control system includes: a first building module 10 , an acquisition module 20 , a second building module 30 , a third building module 40 , an estimation module 50 and a control module 60 .

[0081] Among them, the first construction module 10 is used to construct the robot's link coordinate system using the DH parameter method; the acquisition module 20 is used to split the secondary term of the velocity vector into two different inputs according to the Newton-Euler method, and obtain the recursive expression of the angular velocity and acceleration of each link of the robot and the linear acceleration of the origin and center of mass of the coordinate system; the second construction module 30 is used to establish the robot's dynamic equation according to the robot's driving torque and the external torque in the robot's physical interaction with the outside world; the third construction module 40 is used to obtain the robot's centrifugal force and Coriolis moment terms according to the recursive expression Gravity vector G(q), based on generalized momentum p, centrifugal force, and Coriolis moment terms and the gravity vector G(q) to construct a generalized momentum observer; the estimation module 50 is used to apply external force during the operation of the robot, obtain the driving torque of the robot according to the current information of the robot, input the driving torque into the generalized momentum observer, and estimate the external torque in the physical interaction between the robot and the outside world according to the output of the generalized momentum observer; the control module 60 is used to obtain the impedance control model, generate a reference position signal according to the external torque and the impedance control model, and perform compliant control of the robot according to the reference position signal.

[0082] In summary, the compliant control system of the robot according to the embodiment of the present invention, by constructing an accurate robot dynamics model and combining a generalized momentum observer, infers the external force generated during the interaction between the robot and the outside world, without relying on physical force sensors. This model-based force estimation technology not only significantly reduces the hardware cost, but also simplifies the system design and maintenance process, and improves the reliability and maintainability of the system. The present invention adopts an improved Newton-Euler method when obtaining the dynamics equation, splitting the secondary term of the velocity vector into two different inputs, so that it can be applied to robots with more degrees of freedom.

[0083] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0084] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0085] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0086] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0087] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute the instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways if necessary, and then stored in a computer memory.

[0088] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0089] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0090] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0091] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A compliant control method for a robot, characterized in that: The following steps are involved: The DH parameter method is used to construct the robot's link coordinate system; According to the Newton-Euler method, the secondary term of the velocity vector is split into two different inputs to obtain the recursive expressions of the angular velocity and acceleration of each link of the robot and the linear acceleration of the origin and center of mass of the coordinate system; Establishing a dynamic equation of the robot according to the driving torque of the robot and the external torque in the physical interaction between the robot and the outside world; Obtain the centrifugal force and Coriolis moment of the robot according to the recursive expression Gravity vector G(q), based on generalized momentum p, centrifugal force, and Coriolis moment terms and the gravity vector G(q) to construct a generalized momentum observer; Applying an external force during the operation of the robot, obtaining a driving torque of the robot according to current information of the robot, inputting the driving torque into a generalized momentum observer, and estimating an external torque in a physical interaction between the robot and the outside world according to an output of the generalized momentum observer; An impedance control model is obtained, a reference position signal is generated according to the external torque and the impedance control model, and compliance control of the robot is performed according to the reference position signal.

2. The robot compliance control method according to claim 1, characterized in that: The recursive expression is obtained according to the following formula: in, represents the angular velocity of joint i, represents the auxiliary angular acceleration of joint i, ω i is the angular velocity of connecting rod i, is the auxiliary angular velocity of connecting rod i, represents the linear acceleration of the origin of the i-link coordinate system; represents the linear acceleration at the mass center of the i-link; r i-1,i represents the vector from the i-1th joint to the i-th joint. represents the vector from the i-th joint to the center of mass of the link, ω i represents the angular velocity of connecting rod i, is the angular acceleration of connecting rod i, represents the auxiliary angular velocity of link i, τ i represents the torque of joint i, f i represents the force at joint i, f i+1 represents the force at the i+1 joint, I i represents the inertia matrix of the i link, z i Represents the vector along the i-axis direction, which is [0 0 1] T ,u i It represents the torque in the z-axis direction required for the robot to move at a given speed and acceleration.

3. The robot compliance control method according to claim 1, characterized in that: Specifically, the dynamic equation of the robot is obtained according to the following formula; Where q represents the joint angle, represents the joint angular velocity, represents the joint angular acceleration, M(q) represents the inertia tensor, represents the centrifugal force and Coriolis moment term, G(q) represents the gravity vector, τ d represents the driving torque; τ e Represents the external torque in the physical interaction between the robot and the outside world.

4. The robot compliance control method according to claim 1, characterized in that: The generalized momentum is obtained according to the following formula: Where p represents generalized momentum, M(q) represents the inertia tensor, and q represents the joint angle. Represents the joint angular velocity.

5. The robot compliance control method according to claim 4, characterized in that: The generalized momentum observer is constructed according to the following formula: Where r(t) represents the output of the generalized momentum observer, K represents the observer gain coefficient, for The transposed matrix of represents centrifugal force and Coriolis moment term, G(q) represents gravity vector, and p represents generalized momentum.

6. The robot compliance control method according to claim 1, characterized in that: The impedance control model is obtained according to the following formula: Among them, M d represents the simulated mass matrix, D d represents the damping matrix, K d represents the stiffness matrix, q d ,q r Represent the reference position and actual position of the robot, τ e represents the external torque, Represents the joint angle of the robot when it is actually running, Represents the joint angular velocity of the robot during actual operation.

7. The compliant control method of a robot according to any one of claims 1 to 6, characterized in that: The robot is a six-degree-of-freedom robot.

8. A compliant control system for a robot, characterized in that: include: A first construction module, wherein the first construction module is used to construct a connecting rod coordinate system of the robot using a DH parameter method; An acquisition module, which is used to split the secondary term of the velocity vector into two different inputs according to the Newton-Euler method, and obtain the recursive expressions of the angular velocity and acceleration of each link of the robot and the linear acceleration of the origin and center of mass of the coordinate system; A second building block, the second building block is used to establish a dynamic equation of the robot according to a driving torque of the robot and an external torque in a physical interaction between the robot and the outside world; A third building block, the third building block is used to obtain the centrifugal force and Coriolis moment terms of the robot according to the recursive expression Gravity vector G(q), based on generalized momentum p, centrifugal force, and Coriolis moment terms and the gravity vector G(q) to construct a generalized momentum observer; an estimation module, the estimation module being used to apply an external force during the operation of the robot, obtain a driving torque of the robot according to the current information of the robot, input the driving torque into a generalized momentum observer, and estimate an external torque in a physical interaction between the robot and the outside world according to an output of the generalized momentum observer; A control module is used to obtain an impedance control model, generate a reference position signal according to the external torque and the impedance control model, and perform compliant control of the robot according to the reference position signal.

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