Cable-driven parallel robot force-position hybrid control method, device and medium

Abstract

The application discloses a rope traction parallel robot force-position hybrid control method, equipment and medium, and belongs to the field of rope traction parallel robot control. The method comprises the following steps: step 1, establishing a kinematics and dynamics model of the robot; step 2, dividing a hierarchical priority of contact force tracking, trajectory tracking and rope tension distribution subtasks according to a rich contact operation task constraint; step 3, in the contact force tracking subtask, constructing a guide controller based on a disturbance observer according to a deformation model and tracking the contact force; step 4, in the trajectory tracking subtask, constructing a sliding mode controller based on the disturbance observer according to a control target in the form of a sliding mode surface and tracking the trajectory; step 5, constructing a motor speed controller according to the controller output in steps 3 and 4 and combining an artificial potential field rope tension distribution algorithm of the rope tension distribution subtask; and step 6, performing robot force-position hybrid control by using the motor speed controller to complete the rich contact operation task.

Description

Technical Field

[0001] This invention relates to the field of control of rope-traction parallel robots, and more particularly to a force-position hybrid control method for rope-traction parallel robots. Background Technology

[0002] As a novel type of parallel robot, the rope-driven parallel robot drives its moving platform using flexible ropes instead of rigid links, thus offering advantages such as low inertia, high speed, strong load capacity, and large workspace. Rope-driven parallel robots are widely used in contactless scenarios such as high-speed and high-load material handling and astronomical observation. Furthermore, the flexibility of the ropes gives rope-driven parallel robots strong compliance, allowing them to be applied in human-robot collaboration and operation scenarios in contact-rich environments (environments where physical contact with the robot occurs).

[0003] A typical operational task involves a desired contact force and a desired trajectory, requiring the robot to simultaneously track both the contact force and the trajectory. This combination is known as force-position hybrid control. Although trajectory tracking in rope-guided parallel robots has been extensively studied, the flexibility of ropes means that rope-guided parallel robots not only deform under contact forces but are also highly sensitive to external disturbances. Therefore, contact force tracking in rope-guided parallel robots has not been fully explored, and their application in operational tasks implemented through force-position hybrid control is limited.

[0004] Besides rope flexibility, another factor affecting the force-position hybrid control performance of rope-traction parallel robots is the unidirectional force characteristic of the rope, meaning the rope can only apply tension and not thrust. Therefore, rope-traction parallel robots need to maintain the rope tension within a suitable range through rope tension distribution algorithms. Currently, rope-traction parallel robots often neglect rope tension distribution or only consider simple closed-loop rope tension distribution during force-position hybrid control, leading to ropes becoming too tight or too loose during complex, contact-rich operations. Therefore, providing a method for force-position hybrid control of rope-traction parallel robots that achieves high-precision contact force tracking, trajectory tracking, and rope tension distribution is an urgent problem to be solved.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a force-position hybrid control method, device, and medium for rope-traction parallel robots, which can achieve high-precision contact force tracking and trajectory tracking, and simultaneously implement rope tension distribution based on an artificial potential field to achieve high-precision force-position hybrid control of rope-traction parallel robots, thereby solving the above-mentioned problems existing in the prior art.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A force-position hybrid control method for a rope-traction parallel robot includes:

[0009] Step 1: Establish the kinematic and dynamic models of the rope-traction parallel robot;

[0010] Step 2: Based on the kinematic constraints of the rope-traction parallel robot in contact-rich operation tasks, divide the contact force tracking sub-task, trajectory tracking sub-task, and rope tension distribution sub-task into hierarchical priorities, and decouple the velocity subspace and dynamic model according to the determined hierarchical priorities.

[0011] Step 3: In the contact force tracking subtask, construct an admittance controller based on a disturbance observer and perform contact force tracking according to the determined deformation model of the parallel robot and the contact surface by the rope traction.

[0012] Step 4: In the trajectory tracking subtask, according to the control objective having the form of a sliding surface, construct a sliding mode controller based on a disturbance observer and perform trajectory tracking;

[0013] Step 5: Based on the output of the admittance controller in Step 3 and the output of the sliding mode controller in Step 4, and combined with the rope tension distribution algorithm based on artificial potential field in the rope tension distribution subtask, construct a motor speed controller based on rope tension feedback.

[0014] Step 6: Use the motor speed controller from Step 5 to perform force-position hybrid control on the rope-traction parallel robot, so that the rope-traction parallel robot maintains the desired contact force with the contact surface while satisfying the rope tension constraint, and moves along the desired trajectory to complete the contact-rich operation task.

[0015] Preferably, in the above method, the rope-driven parallel robot pulls a moving platform with n degrees of freedom through m ropes, and one end of the i-th rope is connected to the connection point A of the moving platform. i Above, i=1,…,m, the other end of the i-th rope passes over a pulley and is wound and fixed to a drum on the rope-traction parallel robot frame, and has an equivalent rope exit point B. i The tension and release of the ropes are changed by the winch of the motor, and the number of ropes m is greater than the degree of freedom n of the moving platform.

[0016] Preferably, in step 1 of the above method, the kinematic model of the rope-traction parallel robot is established in the following manner:

[0017] The pose of the moving platform of the rope-driven parallel robot is expressed in Cartesian space coordinates. In this representation, p represents the coordinates of the center of mass of the moving platform in the global coordinate system O-xyz with the origin located on the ground, θ represents the Euler angles of the moving platform's attitude, and the superscript T represents the transpose of the matrix.

[0018] The actual rope length l of the rope-driven parallel robot i Let i = 1, ..., m, where m represents the number of ropes in the rope-driven parallel robot, taking a positive integer, i.e., the connection point A. i Point B, indexed by the rope i Spacing A i B i The relationship between the pose and the position of the moving platform is:

[0019] (1);

[0020] Among them, a i Indicates connection point A i The coordinates in the local coordinate system P-xyz, where the origin is located at the center of mass of the moving platform; b i Indicates the point B where the rope originates. i The coordinates of the origin located on the ground in the global coordinate system O-xyz; The rotation matrix represents the moving platform of the rope-driven parallel robot;

[0021] Combining the time-varying differentials of the kinematic model of equation (1) at i=1,…,m and writing it in the following stacked form:

[0022] (2);

[0023] in, Indicates the speed of the rope's movement; The Jacobian matrix representing the Cartesian velocity space and the rope length velocity space; Let represent the velocity of the moving platform of the rope-driven parallel robot, and be the differential of the moving platform's pose with time.

[0024] Based on the kinematic model of equation (1) above, the Jacobian matrix of equation (2) is determined, and the dynamic model of the rope-traction parallel robot is established by the Newton-Euler method as follows:

[0025] (3);

[0026] in, The inertia matrix of the rope-driven parallel robot is a positive definite symmetric matrix, hereinafter denoted by M; Let represent the acceleration of the moving platform of the rope-driven parallel robot, and be the second derivative of the moving platform's pose with time. The term G represents the Coriolis matrix, hereinafter denoted by C; G, T and These represent gravity, rope tension, and external contact force in the rope-driven parallel robot, respectively. For antisymmetric matrices, This indicates the rate of change of the inertia matrix of a rope-driven parallel robot. Let represent the transpose of the Jacobian matrix; since the rope is elastic, the relationship between the rope tension T and the rope deformation ql is:

[0027] (4);

[0028] Where K is a diagonal matrix representing the elastic modulus of the rope; q is the nominal rope length obtained by solving the joint angle of the motor of the parallel robot through rope traction; and the rope deformation ql is represented by the difference between the nominal rope length q and the actual rope length vector l.

[0029] Preferably, in step 2 of the above method, the contact force tracking subtask, trajectory tracking subtask, and rope tension distribution subtask are prioritized according to the kinematic constraints experienced by the rope-traction parallel robot in a contact-rich operation task, as follows:

[0030] The kinematic constraints on the rope-driven parallel robot in a contact-rich operation task are determined as follows:

[0031] The pose of the rope-driven parallel robot is subject to kinematic constraints described by an r-dimensional continuously differentiable function. r is a non-negative integer representing the dimension of the kinematic constraints. This represents the initial value of the motion variable corresponding to the change in contact force of the rope-driven parallel robot. The change in contact force is achieved through the movement of the rope-driven parallel robot in the direction perpendicular to the contact surface, and the change in pose is achieved through the movement of the rope-driven parallel robot in Cartesian space. The initial value of the motion variable corresponding to the change in contact force of the rope-driven parallel robot is... and motion variables corresponding to pose changes The definitions are as follows:

[0032] (5);

[0033] For the motion variables corresponding to the change in contact force and motion variables corresponding to pose changes Taking the derivative with time yields:

[0034] (6);

[0035] Among them, represents the motion speed corresponding to the change in contact force, represents the motion speed corresponding to the change in pose, represents including and the combined Jacobian matrix of, represents the Jacobian matrix that maps the velocity space to the subspace corresponding to the change in contact force, is a full-rank matrix of r×n dimensions, and r < n, where n represents the degrees of freedom of the moving platform of the cable-driven parallel robot, taking positive integers, represents the kinematic constraint described by an r-dimensional continuously differentiable function; represents the Jacobian matrix that maps the velocity space to the subspace corresponding to the change in pose;

[0036] Under the kinematic constraint of the cable-driven parallel robot, according to the change in contact force, it has complete feasibility, and for the change in pose, it only has partial feasibility. It is determined that the contact force tracking subtask has a high hierarchical priority, the trajectory tracking subtask has a medium hierarchical priority, and the cable tension distribution subtask has a low hierarchical priority.

[0037] Preferably, in step 2 of the above method, the velocity subspace decoupling is performed with the determined hierarchical priority in the following manner, including:

[0038] Based on formula (6), the velocities related to the contact force tracking subtask are respectively defined by the null space projection method and the velocities related to the trajectory tracking subtask as:

[0039] (7);

[0040] Among them, , are respectively the Jacobian matrices of two subspaces of the velocity space, represents including and the combined Jacobian matrix of, and represents the dynamic consistent pseudoinverse of, where represents the Moore-Penrose pseudoinverse of the matrix;

[0041] Since the Jacobian matrices and satisfy , where, represents the Jacobian matrix The dynamically consistent pseudo-inverse transforms formula (7) into:

[0042] (8);

[0043] in, Represents the combined Jacobian matrix Dynamically consistent pseudo-inverse;

[0044] Formula (8) determines that the two subspaces of the velocity space of the rope-driven parallel robot are decoupled, and these two subspaces fill the velocity space of the rope-driven parallel robot.

[0045] Preferably, in step 2 of the above method, the hierarchical decoupling of the dynamic model established in step 1 is performed in the following manner:

[0046] According to formula (8), the dynamic model (4) of the rope-traction parallel robot is transformed into:

[0047] (9);

[0048] in, This represents the acceleration corresponding to the change in contact force. This represents the acceleration corresponding to the change in pose. , , , This represents the transpose of the dynamically consistent pseudoinverse of the combinatorial Jacobian matrix. This represents the rate of change of the dynamically consistent pseudoinverse of the combined Jacobian matrix; considering... The stacking form, and Write it in the following block format:

[0049] (10);

[0050] in, The inertia matrix represents the dynamic model associated with the contact force tracking subtask; The inertia matrix representing the influence of the contact force tracking subtask on the trajectory tracking subtask; The inertia matrix representing the impact of the trajectory tracking subtask on the contact force tracking subtask; The inertia matrix represents the dynamic model associated with the trajectory tracking subtask; The Coriolis matrix representing the dynamic model associated with the contact force tracking subtask; The Coriolis matrix represents the influence of the contact force tracking subtask on the trajectory tracking subtask; The Coriolis matrix representing the influence of the trajectory tracking subtask on the contact force tracking subtask; The Coriolis matrix representing the dynamic model associated with the trajectory tracking subtask;

[0051] And the diagonal submatrix and It is also an antisymmetric matrix; among which, This represents the rate of change of the inertia matrix of the dynamic model associated with the contact force tracking subtask; This represents the rate of change of the inertia matrix of the dynamic model associated with the trajectory tracking subtask;

[0052] Since the matrix is , It can be derived that , The transformed dynamic model (9) is further decomposed into a dynamic model related to the contact force tracking sub-task, as follows:

[0053] (11);

[0054] Among them, the gravitational component corresponding to the change in contact force. ;

[0055] The dynamic model related to the trajectory tracking subtask is as follows:

[0056] (12);

[0057] in, This represents the gravitational component corresponding to the change in pose, and the equivalent torque corresponding to the change in contact force. Equivalent torque corresponding to pose change Contact force and They represent contact forces respectively. Components in the two subspaces This represents the contact force perpendicular to the contact surface. This represents the contact force parallel to the direction of the contact surface; due to and It has dynamic consistency. and No acceleration is generated in another dynamic model. The dynamic model related to the contact force tracking subtask in equation (11) and the dynamic model related to the trajectory tracking subtask in equation (12) are hierarchically decoupled. The controllers of the rope-traction parallel robot, which are built based on the dynamic model related to the contact force tracking subtask in equation (11) and the dynamic model related to the trajectory tracking subtask in equation (12), are independent of each other and do not interfere with each other.

[0058] Preferably, in step 3 of the above method, in the contact force tracking subtask, the deformation model of the rope-traction parallel robot and the contact surface is determined in the following manner, and then an admittance controller based on a disturbance observer is constructed according to the deformation model and contact force tracking is performed, including:

[0059] The deformation of the rope-traction parallel robot under contact force is determined by the nominal pose in the contact force tracking subtask. With actual pose The difference between them, and the nominal pose in the contact force tracking subtask The change is determined by the change in the nominal rope length of the rope-pulled parallel robot, and the nominal velocity in the contact force tracking subtask. Speed ​​with nominal rope length The relationship is:

[0060] (13);

[0061] in, Represents the Moore-Penrose pseudoinverse of the Jacobian matrix;

[0062] Based on the nominal pose in the contact force tracking subtask The relationship with the nominal rope length q allows us to write the dynamic model of equation (11) related to the contact force tracking subtask as follows:

[0063] (14);

[0064] in, This represents the acceleration of the nominal pose in the contact force tracking subtask; This represents the velocity of the nominal pose in the contact force tracking subtask; Represents motion variables related to the contact force tracking subtask;

[0065] The dynamic model related to the contact force tracking subtask in equation (11) is decomposed into the following nominal model and sub-deformation model, where the nominal model is:

[0066] (15);

[0067] The sub-deformation model is:

[0068] (16);

[0069] In the subdeformation model of equation (16), the stiffness matrix for:

[0070] (17);

[0071] The relationship between the deformation and contact force of the rope-driven parallel robot is described by the sub-deformation model of equation (16). The deformation model of the contact surface is written in the following spring-damped form:

[0072] (18);

[0073] in, This indicates the initial velocity of the contact force tracking subtask at the contact surface;

[0074] In the above formula (18), This indicates the pose of the initial contact force tracking subtask at the contact surface; and These represent the stiffness and damping of the contact surface, respectively.

[0075] The sub-deformation model parameters of the rope-traction parallel robot , and The deformation model of the contact surface in Equation (18) is obtained through offline identification, but the parameters are unknown and the shape of the contact surface is uncertain. Based on this, the deformation model of the contact surface of the rope-pulled parallel robot is written in the following transfer function form:

[0076] (19);

[0077] In the above formula (19), This represents the contact force in the contact force tracking subtask; s represents the Laplace variable; This represents the nominal value of the initial contact force tracking subtask pose; total perturbation. writing:

[0078] (20);

[0079] The rope-traction parallel robot adjusts the nominal rope length by controlling the motor rotation angle, and changes the nominal pose of the rope-traction parallel robot in the contact force tracking subtask according to equation (13). And control the contact force Given a desired contact force Then, the nominal pose in the contact force tracking subtask is used. As the control variable, the admittance controller based on the disturbance observer for contact force tracking is constructed as follows:

[0080] (twenty one);

[0081] in, Indicates the quality parameters of the admittance controller; Indicates the damping parameters of the admittance controller;

[0082] In the above formula (21), Indicates the impact of disturbances The observed values.

[0083] Preferably, in step 4 of the above method, in the trajectory tracking subtask, a sliding mode controller based on a disturbance observer is constructed and trajectory tracking is performed according to the control objective having a sliding surface form, including:

[0084] The rope-traction parallel robot is subjected to... The kinematic constraints are represented by The trajectory tracking subtask for the desired trajectory can be represented as the following optimization problem:

[0085] (twenty two);

[0086] In the above formula (22), Indicates trajectory tracking error; Indicates the trajectory tracking error rate; These represent the design parameters of the sliding mode function, and are usually taken as positive real numbers.

[0087] The solution to the optimization problem of equation (22) needs to satisfy... Then the sliding mode function The convergence is defined as the control objective of the trajectory tracking subtask in the contact-rich operation task performed by the rope-pulled parallel robot.

[0088] Let the output of the sliding mode controller be At this point, the dynamic model of equation (12) related to the trajectory tracking subtask can be written in the following perturbation form:

[0089] (twenty three);

[0090] In the above formula (23), This represents the total disturbance in the dynamic model; it is used to represent the total disturbance. To conduct observations, construct the following perturbation observer:

[0091] (twenty four);

[0092] In equation (24), Indicates total disturbance Observations The rate of change; Indicates the intermediate variable of torque; Indicates the gain of the perturbation observer; , These are positive real numbers that serve as parameters for the perturbation observer;

[0093] The sliding mode controller based on a disturbance observer for trajectory tracking of the rope-traction parallel robot is constructed as follows:

[0094] (25);

[0095] In equation (25), Output of the sliding mode controller; dynamic compensation term for:

[0096] (26);

[0097] Let be the gain matrix, where It is a positive definite diagonal matrix; For the positive gain of the robust term, according to , The pattern iterates online, where t represents time. Indicate intermediate variables The rate of change Indicate intermediate variables The update step size takes the value of a positive real number; Indicates the desired acceleration; Indicates the desired speed; Representing the Jacobian matrix The rate of change of the dynamically consistent pseudo-inverse;

[0098] In step 5, based on the output of the admittance controller in step 3 and the output of the sliding mode controller in step 4, and combined with the rope tension distribution algorithm based on the artificial potential field in the rope tension distribution subtask, a motor speed controller based on rope tension feedback is constructed, including:

[0099] Given the nominal pose in step 3 as the contact force tracking subtask The output of the admittance controller and the output of the sliding mode controller in step 4 Afterwards, the motor speed of the rope-driven parallel robot needs to satisfy the relationship between the nominal pose and the nominal rope length in the contact force tracking subtask of equation (13), and the rope tension T needs to satisfy the following equation constraint:

[0100] (27);

[0101] and the lower limit of rope tension and upper limit The following inequality constraints are defined:

[0102] (28);

[0103] Based on this, the constructed motor speed controller based on rope tension feedback is as follows:

[0104] (29);

[0105] In equation (29), Indicates the motor speed; This indicates the rate of change of the rope tension T;

[0106] Wherein, the derivative of the rope tension T with time satisfies:

[0107] (30);

[0108] In equation (30), The proportional coefficient representing the rope tension control. The integral coefficient representing rope tension control;

[0109] So that the rope tension satisfies the equality constraint of equation (27);

[0110] To ensure that the rope tension satisfies the inequality constraint of equation (28), an artificial potential field function is introduced. The attractive items With exclusion term They are respectively:

[0111] (31);

[0112] In equation (31), , Indicates positive gain; This indicates the reference tension within the upper and lower limits of the rope tension. Indicates the distance of influence of the exclusion term;

[0113] The rope tension distribution based on the artificial potential field needs to satisfy the following:

[0114] (32);

[0115] in, It is a positive gain; Substitute equations (30) and (32) into equation (29) to construct a motor speed controller based on rope tension feedback, and realize the motor speed control of the rope-traction parallel robot based on rope tension feedback through the constructed motor speed controller.

[0116] A processing apparatus, comprising:

[0117] At least one memory for storing one or more programs;

[0118] At least one processor is capable of executing one or more programs stored in the memory, such that when the one or more programs are executed by the processor, the processor can implement the method of the present invention.

[0119] A readable storage medium storing a computer program that, when executed by a processor, enables the implementation of the methods described in this invention.

[0120] Compared with the prior art, the rope-traction parallel robot force-position hybrid control method, equipment, and medium provided by the present invention have the following advantages:

[0121] By combining an admittance controller for contact force tracking, a sliding mode controller for trajectory tracking, and a rope tension distribution algorithm in contact-rich operational tasks, this invention achieves high-precision hierarchical force-position hybrid control for rope-traction parallel robots. Firstly, by prioritizing the contact force tracking, trajectory tracking, and rope tension distribution subtasks, contact force tracking, trajectory tracking, and rope tension distribution are unified into a hierarchical control framework, ensuring that the subtasks do not interfere with each other. Secondly, by establishing a dynamic and deformation model of the rope-traction parallel robot, and using a disturbance observer based on the deformation model to construct the admittance controller for contact force tracking and the sliding mode controller for trajectory tracking, the invention compensates for disturbances experienced by the rope-traction parallel robot during force-position hybrid control. Furthermore, a rope tension distribution algorithm based on an artificial potential field ensures that the rope tension remains within a certain range, ultimately improving the accuracy of contact force tracking and trajectory tracking. This method is particularly advantageous for scenarios requiring high accuracy in contact force tracking and trajectory tracking, such as polishing and grinding. Attached Figure Description

[0122] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0123] Figure 1 A flowchart of a force-position hybrid control method for a rope-traction parallel robot provided in an embodiment of the present invention.

[0124] Figure 2 This is a structural schematic diagram of a rope-traction parallel robot provided in an embodiment of the present invention.

[0125] Figure 3 The control block diagram of the admittance controller based on the disturbance observer provided in the embodiment of the present invention.

[0126] Figure 4This is a control block diagram of a motor speed controller based on rope tension feedback provided in an embodiment of the present invention. Detailed Implementation

[0127] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the specific content of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments, which do not constitute a limitation of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0128] First, the following explanations are provided for the terms that may be used in this article:

[0129] The term "and / or" means that either or both can be achieved simultaneously. For example, X and / or Y means that it includes both "X" or "Y" as well as the three cases of "X and Y".

[0130] The terms "comprising," "including," "containing," "having," or other similar semantic descriptions should be interpreted as non-exclusive inclusion. For example, including a technical feature element (such as raw material, component, ingredient, carrier, dosage form, material, size, part, component, mechanism, device, step, process, method, reaction conditions, processing conditions, parameter, algorithm, signal, data, product or article of manufacture, etc.) should be interpreted as including not only the expressly listed technical feature element, but also other technical feature elements that are not expressly listed and are well-known in the art.

[0131] The term "composed of" excludes any technical features not expressly listed. When used in a claim, it closes the claim to exclude all technical features other than those expressly listed, except for associated conventional impurities. If the term appears only in a clause of a claim, it limits the claim to the elements expressly listed in that clause; elements recited in other clauses are not excluded from the overall claim.

[0132] Unless otherwise explicitly specified or limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this document according to the specific circumstances.

[0133] When concentration, temperature, pressure, size, or other parameters are expressed as numerical ranges, such ranges should be understood to specifically disclose all ranges formed by any pairing of upper limits, lower limits, or preferred values ​​within that range, regardless of whether the range is explicitly stated; for example, if the numerical range "2 to 8" is stated, then that range should be interpreted to include ranges such as "2 to 7", "2 to 6", "5 to 7", "3 to 4 and 6 to 7", "3 to 5 and 7", "2 and 5 to 7", etc. Unless otherwise stated, the numerical ranges described herein include both their endpoints and all integers and fractions within that range.

[0134] The terms “center,” “longitudinal,” “lateral,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “back,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” and “counterclockwise” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience and simplification of description and do not imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this document.

[0135] The solution provided by this invention will be described in detail below. Contents not described in detail in the embodiments of this invention are prior art known to those skilled in the art. Where specific conditions are not specified in the embodiments of this invention, they shall be performed according to conventional conditions in the art or conditions recommended by the manufacturer. Reagents or instruments used in the embodiments of this invention whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0136] Example

[0137] like Figure 1 As shown, this embodiment of the invention provides a force-position hybrid control method for a rope-traction parallel robot, comprising the following steps:

[0138] Step 1: Establish the kinematic and dynamic models of the rope-traction parallel robot;

[0139] Step 2: Based on the kinematic constraints of the rope-traction parallel robot in contact-rich operation tasks, divide the contact force tracking subtask, trajectory tracking subtask, and rope tension distribution subtask into hierarchical priorities, and decouple the velocity subspace and dynamic model according to the determined hierarchical priorities; thus realizing the decoupling of the velocity subspace and dynamic model of the rope-traction parallel robot.

[0140] Step 3: In the contact force tracking subtask, determine the deformation model of the rope-traction parallel robot and the contact surface, construct an admittance controller based on the disturbance observer according to the deformation model, and perform contact force tracking.

[0141] Step 4: In the kinematically constrained trajectory tracking subtask, construct a sliding mode controller based on a disturbance observer according to the control objective having a sliding surface form and perform trajectory tracking;

[0142] Step 5: Based on the output of the admittance controller in Step 3 and the output of the sliding mode controller in Step 4, and combined with the rope tension distribution algorithm based on artificial potential field in the rope tension distribution subtask, construct a motor speed controller based on rope tension feedback.

[0143] Step 6: Use the motor speed controller from Step 5 to perform force-position hybrid control on the rope-traction parallel robot, so that the rope-traction parallel robot maintains the desired contact force with the contact surface while satisfying the rope tension constraint, and moves along the desired trajectory to complete the contact-rich operation task.

[0144] like Figure 2 As shown, in the rope-driven parallel robot controlled by the above method, the rope-driven parallel robot pulls a moving platform 10 with n degrees of freedom through m ropes, where n is a positive integer. The ropes are lightweight elastic ropes. Rope 1 is labeled 1, rope 2 is labeled 2, rope i is labeled 13, and rope m is labeled 14, where m and n are positive integers. One end of the i-th (i=1,…,m) rope is connected to connection point A of the moving platform. i The other end passes over a pulley and is wound around the drum of the rope traction parallel robot frame, and has an equivalent rope traction point B. i The tension and release of the ropes are changed by the winch of the motor, and the number of ropes m is greater than the degree of freedom n of the moving platform, thereby realizing redundant drive of the rope-traction parallel robot and implementing tension distribution while the moving platform is moving. Figure 2 In the diagram below the moving platform 10, the initial and actual positions of the contact surface 17 are shown. The ellipse represents the desired trajectory 16, and the marker 18 represents the mass-spring-damping deformation model.

[0145] Preferably, in step 1 of the above method, the kinematic and dynamic models of the rope-traction parallel robot are established in the following manner:

[0146] like Figure 2 As shown, two coordinate systems were used in the kinematic analysis of the rope-driven parallel robot: a global coordinate system O-xyz with its origin at the ground and a local coordinate system P-xyz with its origin at the center of mass of the moving platform. The Cartesian coordinates representing the pose of the moving platform are written as... Where p represents the coordinates of the center of mass P of the moving platform in O-xyz, and θ is the Euler angle representing the attitude of the moving platform. At this point, the actual rope length of the rope-driven parallel robot... Ai B i The relationship between the spacing and the pose of the moving platform, i.e., the kinematic model, is as follows:

[0147] (1);

[0148] Among them, a i Indicates connection point A i The coordinates in P-xyz, b i Indicates the point B where the rope originates. i Coordinates in O-xyz, Let represent the rotation matrix. The time derivative of formula (1) at i=1,…,m can be combined and written in the following stacked form:

[0149] (2);

[0150] in, Indicates the speed of the rope's movement; Let represent the Jacobian matrix between the Cartesian velocity space and the rope length velocity space. Considering the elasticity of the rope, the relationship between the rope tension T and the rope deformation of the rope-traction parallel robot in this embodiment is as follows:

[0151] (3);

[0152] Where K is a diagonal matrix representing the elastic modulus of the rope, q is the nominal rope length obtained by solving the joint angle of the parallel robot motor through rope traction, and the rope deformation is represented as the difference between the nominal rope length q and the actual rope length vector l.

[0153] Furthermore, based on the Jacobian matrix of equation (2) determined by the kinematic model of equation (1) above, the following dynamic model of the rope-traction parallel robot can be established using the Newton-Euler method:

[0154] (4);

[0155] in, The inertia matrix representing the dynamic model of the rope-traction parallel robot is a positive definite symmetric matrix, hereinafter denoted by M; Let represent the acceleration of the moving platform of the rope-driven parallel robot, and be the second derivative of the moving platform's pose with time. The term G represents the Coriolis matrix, hereinafter denoted by C; G, T and These represent gravity, rope tension, and external contact force, respectively. For antisymmetric matrices, This indicates the rate of change of the inertia matrix of a rope-driven parallel robot. This represents the transpose of the Jacobian matrix.

[0156] In step 2 of the above method, based on the kinematic constraints experienced by the rope-traction parallel robot in a contact-rich operation task, the priorities of the contact force tracking subtask, trajectory tracking subtask, and rope tension distribution subtask are divided into hierarchical priorities as follows:

[0157] In a contact-rich operational task involving interaction with the environment, the rope-driven parallel robot of this embodiment needs to keep the end effector mounted on the moving platform on a specific contact surface and maintain a certain contact force. Therefore, the pose X is subject to kinematic constraints described by an r-dimensional continuously differentiable function. r is a non-negative integer representing the dimension of the kinematic constraint.

[0158] During the execution of the operation task, changes in contact force are achieved through the movement of the parallel robot perpendicular to the contact surface, while changes in pose are achieved through the movement of the parallel robot in Cartesian space. Therefore, the corresponding motion variables are defined as follows:

[0159] (5);

[0160] And the derivatives of both over time are written as follows:

[0161] (6);

[0162] in, , Let represent the Jacobian matrices that map the velocity space to the subspaces corresponding to changes in contact force and pose, respectively. The kinematic constraints on the rope-driven parallel robot in this embodiment do not cover the entire Cartesian space, therefore... It is an r×n dimensional full-rank matrix, and r <n。

[0163] The rope-traction parallel robot in this embodiment needs to simultaneously track the desired contact force through force-position hybrid control during operation. With the expected trajectory The subtask of contact force tracking. However, the velocity associated with the contact force tracking subtask. Speed ​​related to the trajectory tracking subtask There is a coupling relationship between the velocity subspaces they occupy. This results in the rope-traction parallel robot in this embodiment being unable to simultaneously track the desired contact force. With the expected trajectory Therefore, the definitions of the above subtasks and their corresponding velocity subspaces need to satisfy hierarchical consistency, so that the execution process of subtasks with high hierarchical priority is not affected by subtasks with low hierarchical priority. Considering that under the kinematic constraints of this embodiment, changing the contact force is fully feasible, while changing the pose is only partially feasible, the contact force tracking subtask (FT subtask) is defined as having high hierarchical priority, the trajectory tracking subtask (TT subtask) as having medium hierarchical priority, and the rope tension distribution subtask as having low hierarchical priority. Based on formula (6), the velocities (FT velocities) related to the contact force tracking subtask are defined as follows using the null space projection method. And the speed (TT speed) associated with the trajectory tracking subtask :

[0164] (7);

[0165] The Jacobian matrix , The velocity subspaces related to the contact force tracking subtask and the trajectory tracking subtask were defined respectively, and... express The dynamically consistent pseudoinverse. Due to the matrix and satisfy , Formula (7) can be transformed into:

[0166] (8);

[0167] This indicates that the velocity subspace related to the contact force tracking subtask and the velocity subspace related to the trajectory tracking subtask in the velocity space of the rope-driven parallel robot in this embodiment are decoupled, and these two subspaces fill the velocity space of the rope-driven parallel robot.

[0168] Furthermore, the dynamic model of equation (4) can be transformed into:

[0169] (9);

[0170] in, , , ,and It is also an antisymmetric matrix. Considering... The stacking form, and It can be written in the following block format:

[0171] (10);

[0172] And the diagonal submatrix , It is also an antisymmetric matrix.

[0173] Since the matrix is , It can be deduced that , Therefore, the transformed dynamic model of equation (9) can be further decomposed into the dynamic model related to the contact force tracking subtask, equation (11), as follows:

[0174] (11);

[0175] Among them, the gravitational component corresponding to the change in contact force. ;

[0176] The dynamic model related to the trajectory tracking subtask in equation (12) is as follows:

[0177] (12);

[0178] in, Represents the gravitational components corresponding to pose changes, equivalent torque , ,external force , They represent The components in the two subspaces. In particular, This represents the contact force perpendicular to the contact surface. This represents the contact force parallel to the direction of the contact surface. Because... and It has dynamic consistency. and No acceleration is generated in the other dynamic model. Therefore, the two dynamic models that realize Equation (11) and Equation (12) are hierarchically decoupled. The controller design based on the two dynamic models of Equation (11) and Equation (12) can be carried out independently without interfering with each other.

[0179] Preferably, in step 3 of the above method, in the contact force tracking subtask, the deformation model of the rope-driven parallel robot and the contact surface is determined in the following manner, and an admittance controller based on a disturbance observer is constructed using the deformation model to achieve contact force tracking, including:

[0180] Because the rope used in this embodiment of the rope-driven parallel robot has a certain degree of flexibility, the contact force causes deformation between the rope-driven parallel robot and the contact surface. The deformation of the rope-driven parallel robot is determined by the nominal pose in the contact force tracking subtask. Pose tracking subtask with actual contact force The difference description between them, and the nominal pose in the contact force tracking subtask. The change is determined by the change in the nominal rope length of the rope-driven parallel robot, and the relationship between the two is as follows:

[0181] (13);

[0182] The dynamic model related to the contact force tracking subtask in equation (11) can be written as:

[0183] (14);

[0184] This can then be decomposed into the nominal model of equation (15):

[0185] (15);

[0186] Sub-deformation model with equation (16):

[0187] (16);

[0188] Where the stiffness matrix for:

[0189] (17);

[0190] Equation (16) describes the relationship between the deformation variation and the contact force variation of a rope-driven parallel robot. The deformation model of the contact surface can be written in the following spring-damped form (see...). Figure 2 (Mass-Spring-Damping Deformation Model, labeled 18)

[0191] (18);

[0192] in This represents the pose of the initial contact force tracking subtask at the contact surface. and These represent the stiffness and damping of the contact surface, respectively.

[0193] In this embodiment, the deformation model parameters of the rope-traction parallel robot , and The deformation model parameters of the contact surface are unknown, and the shape of the contact surface is uncertain. Therefore, in this embodiment, the deformation model of the rope-driven parallel robot and the contact surface can be written as the following transfer function:

[0194] (19);

[0195] Where s represents the Laplace variable, This represents the nominal value of the initial contact force tracking subtask pose at the contact surface, and the total perturbation. writing:

[0196] (20);

[0197] In this embodiment, the nominal rope length of the rope-driven parallel robot can be adjusted by controlling the joint angles of the rope, thereby changing the nominal pose of the rope-driven parallel robot according to formula (13). And control the contact force Given a desired contact force Then, using this as the equivalent control variable, the following admittance controller based on the disturbance observer is constructed:

[0198] (twenty one)

[0199] in Indicates the impact of disturbances The observed values. The control block diagram of the admittance controller is as follows. Figure 3 As shown, the closed-loop transfer function is written as follows:

[0200] (twenty two);

[0201] in It is a low-pass filter. This indicates its cutoff frequency. By adjusting... This allows the system (22) to achieve a balance between disturbance compensation and noise suppression, thereby reducing... and The error between them is used to achieve contact force tracking.

[0202] Preferably, in step 4 of the above method, in the kinematically constrained trajectory tracking subtask, a sliding mode controller based on a disturbance observer is constructed and trajectory tracking is achieved according to a control objective having a sliding surface form, including:

[0203] Because in this embodiment, the rope-traction parallel robot is subjected to... The kinematic constraints are represented by The trajectory tracking subtask for the desired trajectory should be expressed as the following optimization problem:

[0204] (twenty three);

[0205] in This represents the trajectory tracking error. The solution to optimization problem (23) needs to satisfy... Therefore, sliding mode function Convergence is defined as the control objective of the trajectory tracking subtask.

[0206] Assume the controller output in this step is At this point, the dynamic model of equation (12) related to the trajectory tracking subtask can be written in the following perturbation form:

[0207] (twenty four);

[0208] in This represents the total disturbance in the dynamic model. (For...) To conduct observations, construct the following perturbation observer:

[0209] (twenty four);

[0210] in Indicates the intermediate variable of torque. express The observed values. At this point, the constructed sliding mode controller based on the perturbation observer is:

[0211] (25);

[0212] Among them, the dynamic compensation term for:

[0213] (26);

[0214] in Here is the gain matrix. It is a positive definite diagonal matrix. For the positive gain of the robust term, intermediate variable according to The pattern iterates online, with intermediate variables. These are parameters used to ensure system stability during the controller design process.

[0215] Preferably, in step 5 of the above method, a motor speed controller based on rope tension feedback is constructed by combining the output of the admittance controller in step 3 and the output of the sliding mode controller in step 4 with a rope tension distribution algorithm based on an artificial potential field, including:

[0216] Given the controller output in step 3 Compared with the controller output in step 4 Afterwards, the motor speed of the rope-driven parallel robot needs to satisfy equation (13), and the rope tension T in the rope tension distribution subtask needs to satisfy the equality constraint of equation (27):

[0217] (27);

[0218] With the lower limit of rope tension and upper limit Determined inequality constraint (28):

[0219] (28);

[0220] Therefore, the following motor speed controller based on rope tension feedback is designed:

[0221] (29);

[0222] The derivative of the rope tension with time satisfies:

[0223] (30);

[0224] To ensure that the rope tension satisfies the equality constraint of equation (27), an artificial potential field function is introduced to satisfy the inequality constraint of equation (28). ,in,

[0225] (31);

[0226] in and Let represent the attraction and repulsion terms of the artificial potential field, respectively. , Both represent positive gains. This represents the reference tension within the upper and lower limits of the rope tension. The rope tension distribution based on the artificial potential field requires the rope tension to satisfy:

[0227] (32);

[0228] in It is a positive gain. Substituting equations (30) and (32) into equation (29) constructs a motor speed controller based on rope tension feedback. The constructed motor speed controller realizes motor speed control based on rope tension feedback. See the control block diagram. Figure 4 .

[0229] Preferably, in step 6 of the above method, the rope-traction parallel robot is subjected to force-position hybrid control according to the force-position hybrid control method for rope-traction parallel robots. The control block diagram of force-position hybrid control is shown in Figure 4. According to the control method of the present invention, the rope-traction parallel robot can simultaneously complete the contact force tracking sub-task with the desired contact force and the trajectory tracking sub-task with the desired trajectory, while satisfying the rope tension constraint, thereby completing the contact-rich operation task.

[0230] In summary, the hierarchical force-position hybrid control method of this invention establishes a kinematic and dynamic model of a rope-traction parallel robot and, based on the kinematic constraints imposed on the robot, prioritizes subtasks such as contact force tracking, trajectory tracking, and rope tension distribution, thereby achieving decoupling of the velocity subspace and the dynamic model. In the contact force tracking subtask, an admittance controller based on a disturbance observer is constructed based on the deformation model of the rope-traction parallel robot to achieve contact force tracking. In the trajectory tracking subtask, a control objective with a sliding surface form is proposed to address the kinematic constraints, and a sliding mode controller based on a disturbance observer is constructed to achieve trajectory tracking. By controlling the motor speed based on rope tension feedback, the hierarchical force-position hybrid control of this invention can simultaneously and accurately complete subtasks such as contact force tracking, trajectory tracking, and rope tension distribution based on an artificial potential field, thus enabling contact-rich operation tasks.

[0231] Compared with the prior art, the present invention has at least the following beneficial effects:

[0232] By combining a contact force tracking controller, a trajectory tracking controller, and a rope tension distribution algorithm to form a motor speed controller as a hierarchical force-position hybrid controller, high-precision force-position hybrid control of a rope-traction parallel robot is achieved in contact-rich operation tasks.

[0233] (1) By dividing the hierarchical priority among the sub-tasks in the operation task, a hierarchical control framework was established that integrates contact force tracking, trajectory tracking and rope tension distribution, ensuring that the sub-tasks do not interfere with each other.

[0234] (2) By establishing the dynamic model and deformation model of the rope-traction parallel robot, a model-based disturbance observer is used to compensate for the disturbances experienced by the rope-traction parallel robot during the force-position hybrid control process, thereby improving the accuracy of contact force tracking and trajectory tracking.

[0235] (3) By adopting a rope tension distribution algorithm based on artificial potential field, the rope tension of the rope-pulled parallel robot is kept within a certain range, avoiding the need for real-time solution of the desired rope tension and improving the real-time performance of the controller.

[0236] (4) By using motor speed control based on rope tension feedback, the force-position hybrid control of the rope-traction parallel robot is realized, so that the control quantities calculated by the contact force tracking controller and the trajectory tracking controller can be accurately applied to the rope-traction parallel robot. This is especially beneficial for scenarios such as polishing and grinding, which have high requirements for contact force tracking accuracy and trajectory tracking accuracy.

[0237] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0238] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. The information disclosed in the background section is intended only to enhance the understanding of the overall background technology of the present invention and should not be construed as an admission or implication in any way that such information constitutes prior art known to those skilled in the art.

Claims

1. A force-position hybrid control method for a rope-traction parallel robot, characterized in that, include: Step 1: Establish the kinematic and dynamic models of the rope-traction parallel robot; Step 2: Based on the kinematic constraints of the rope-traction parallel robot in contact-rich operation tasks, divide the contact force tracking sub-task, trajectory tracking sub-task, and rope tension distribution sub-task into hierarchical priorities, and decouple the velocity subspace and dynamic model according to the determined hierarchical priorities. In step 2, based on the kinematic constraints experienced by the rope-traction parallel robot in a contact-rich operation task, the priorities of the contact force tracking subtask, trajectory tracking subtask, and rope tension distribution subtask are divided into hierarchical priorities as follows: The kinematic constraints on the rope-driven parallel robot in a contact-rich operation task are determined as follows: The pose of the rope-driven parallel robot is subject to kinematic constraints described by an r-dimensional continuously differentiable function. r is a non-negative integer representing the dimension of the kinematic constraints. This represents the initial value of the motion variable corresponding to the change in contact force of the rope-driven parallel robot. The change in contact force is achieved through the movement of the rope-driven parallel robot in the direction perpendicular to the contact surface, and the change in pose is achieved through the movement of the rope-driven parallel robot in Cartesian space. The initial value of the motion variable corresponding to the change in contact force of the rope-driven parallel robot is... and motion variables corresponding to pose changes The definitions are as follows: (5)； For the motion variables corresponding to the change in contact force and motion variables corresponding to pose changes Taking the derivative with time yields: (6)； Among them, represents the motion speed corresponding to the change in contact force, represents the motion speed corresponding to the change in pose, represents including and the combined Jacobian matrix, represents the Jacobian matrix that maps the velocity space to the subspace corresponding to the change in contact force, is a full-rank matrix of r×n dimension, and r < n, where n represents the degrees of freedom of the moving platform of the cable-driven parallel robot, taking positive integers, represents the kinematic constraint described by an r-dimensional continuously differentiable function; represents the Jacobian matrix that maps the velocity space to the subspace corresponding to the change in pose; The rope-traction parallel robot under kinematic constraints Based on the fact that changing the contact force is fully feasible, while changing the pose is only partially feasible, the contact force tracking subtask is determined to have a high hierarchical priority, the trajectory tracking subtask has a medium hierarchical priority, and the rope tension distribution subtask has a low hierarchical priority. In step 2, velocity subspace decoupling is performed according to the determined hierarchical priority in the following manner: Based on formula (6), the velocities related to the contact force tracking subtask are defined using the null space projection method. and the speed related to the trajectory tracking subtask for: (7)； in, , Let be the Jacobian matrices of the two subspaces of the velocity space, respectively. Indicates inclusion and The combined Jacobian matrix, and express The dynamically consistent pseudoinverse, in which Represents the Moore-Penrose pseudoinverse of a matrix; Due to the Jacobian matrix and satisfy ,in, Representing the Jacobian matrix The dynamically consistent pseudo-inverse transforms formula (7) into: (8)； in, Represents the combined Jacobian matrix Dynamically consistent pseudo-inverse; Formula (8) determines that the two subspaces of the velocity space of the rope-driven parallel robot are decoupled, and these two subspaces fill the velocity space of the rope-driven parallel robot. Step 3: In the contact force tracking subtask, construct an admittance controller based on a disturbance observer and perform contact force tracking according to the determined deformation model of the parallel robot and the contact surface by the rope traction. Step 4: In the trajectory tracking subtask, according to the control objective having the form of a sliding surface, construct a sliding mode controller based on a disturbance observer and perform trajectory tracking; Step 5: Based on the output of the admittance controller in Step 3 and the output of the sliding mode controller in Step 4, and combined with the rope tension distribution algorithm based on artificial potential field in the rope tension distribution subtask, construct a motor speed controller based on rope tension feedback. Step 6: Use the motor speed controller from Step 5 to perform force-position hybrid control on the rope-traction parallel robot, so that the rope-traction parallel robot maintains the desired contact force with the contact surface while satisfying the rope tension constraint, and moves along the desired trajectory to complete the contact-rich operation task.

2. The force-position hybrid control method for a rope-traction parallel robot according to claim 1, characterized in that, The rope-driven parallel robot pulls a moving platform with n degrees of freedom using m ropes, with one end of the i-th rope connected to connection point A of the moving platform. i Above, i=1,…,m, the other end of the i-th rope passes over a pulley and is wound and fixed to a drum on the rope-traction parallel robot frame, and has an equivalent rope exit point B. i The tension and release of the ropes are changed by the winch of the motor, and the number of ropes m is greater than the degree of freedom n of the moving platform.

3. The force-position hybrid control method for a rope-traction parallel robot according to claim 2, characterized in that, In step 1, the kinematic model of the rope-traction parallel robot is established as follows: The pose of the moving platform of the rope-driven parallel robot is expressed in Cartesian space coordinates. In this representation, p represents the coordinates of the center of mass of the moving platform in the global coordinate system O-xyz with the origin located on the ground, θ represents the Euler angles of the moving platform's attitude, and the superscript T represents the transpose of the matrix. The actual rope length l of the rope-driven parallel robot i Let i = 1, ..., m, where m represents the number of ropes in the rope-driven parallel robot, taking a positive integer, i.e., the connection point A. i Point B, indexed by the rope i Spacing A i B i The relationship between the pose and the position of the moving platform is: (1)； Among them, a i Indicates connection point A i The coordinates in the local coordinate system P-xyz, where the origin is located at the center of mass of the moving platform; b i Indicates the point B where the rope originates. i The coordinates of the origin located on the ground in the global coordinate system O-xyz; The rotation matrix represents the moving platform of the rope-driven parallel robot; Combining the time-varying differentials of the kinematic model of equation (1) at i=1,…,m and writing it in the following stacked form: (2)； in, Indicates the speed of the rope's movement; The Jacobian matrix representing the Cartesian velocity space and the rope length velocity space; Let represent the velocity of the moving platform of the rope-driven parallel robot, and be the differential of the moving platform's pose with time. Based on the kinematic model of equation (1) above, the Jacobian matrix of equation (2) is determined, and the dynamic model of the rope-traction parallel robot is established by the Newton-Euler method as follows: (3)； in, The inertia matrix of the rope-driven parallel robot is a positive definite symmetric matrix, hereinafter denoted by M; Let represent the acceleration of the moving platform of the rope-driven parallel robot, and be the second derivative of the moving platform's pose with time. The term G represents the Coriolis matrix, hereinafter denoted by C; G, T and These represent gravity, rope tension, and external contact force in the rope-driven parallel robot, respectively. For antisymmetric matrices, This indicates the rate of change of the inertia matrix of a rope-driven parallel robot. Let represent the transpose of the Jacobian matrix; since the rope is elastic, the relationship between the rope tension T and the rope deformation ql is: (4)； Where K is a diagonal matrix representing the elastic modulus of the rope; q is the nominal rope length obtained by solving the joint angle of the motor of the parallel robot through rope traction; and the rope deformation ql is represented by the difference between the nominal rope length q and the actual rope length vector l.

4. The force-position hybrid control method for a rope-traction parallel robot according to claim 1, characterized in that, In step 2, the hierarchical decoupling of the dynamic model established in step 1 is performed in the following manner: According to formula (8), the dynamic model (4) of the rope-traction parallel robot is transformed into: (9)； in, This represents the acceleration corresponding to the change in contact force. This represents the acceleration corresponding to the change in pose. , , , Denotes the transpose of the dynamically consistent pseudoinverse of the combinatorial Jacobian matrix. This represents the rate of change of the dynamically consistent pseudoinverse of the combined Jacobian matrix; considering... The stacking form, and Write it in the following block format: (10)； in, The inertia matrix represents the dynamic model associated with the contact force tracking subtask; The inertia matrix representing the influence of the contact force tracking subtask on the trajectory tracking subtask; The inertia matrix representing the impact of the trajectory tracking subtask on the contact force tracking subtask; The inertia matrix represents the dynamic model associated with the trajectory tracking subtask; The Coriolis matrix representing the dynamic model associated with the contact force tracking subtask; The Coriolis matrix represents the influence of the contact force tracking subtask on the trajectory tracking subtask; The Coriolis matrix representing the influence of the trajectory tracking subtask on the contact force tracking subtask; The Coriolis matrix representing the dynamic model associated with the trajectory tracking subtask; And the diagonal submatrix and It is also an antisymmetric matrix; among which, This represents the rate of change of the inertia matrix of the dynamic model associated with the contact force tracking subtask; This represents the rate of change of the inertia matrix of the dynamic model associated with the trajectory tracking subtask; Since the matrix is , It can be derived that , The transformed dynamic model (9) is further decomposed into a dynamic model related to the contact force tracking subtask, as follows: (11)； Among them, the gravitational component corresponding to the change in contact force. ; The dynamic model related to the trajectory tracking subtask is as follows: (12)； in, This represents the gravitational component corresponding to the change in pose, and the equivalent torque corresponding to the change in contact force. Equivalent torque corresponding to pose change Contact force and They represent contact forces respectively. Components in the two subspaces This represents the contact force perpendicular to the contact surface. This represents the contact force parallel to the direction of the contact surface; due to and It has dynamic consistency. and No acceleration is generated in another dynamic model. The dynamic model related to the contact force tracking subtask in equation (11) and the dynamic model related to the trajectory tracking subtask in equation (12) are hierarchically decoupled. The controllers of the rope-traction parallel robot, which are built based on the dynamic model related to the contact force tracking subtask in equation (11) and the dynamic model related to the trajectory tracking subtask in equation (12), are independent of each other and do not interfere with each other.

5. The force-position hybrid control method for a rope-traction parallel robot according to claim 4, characterized in that, In step 3, within the contact force tracking subtask, the deformation model of the rope-driven parallel robot and the contact surface is determined as follows: Then, an admittance controller based on a disturbance observer is constructed according to the deformation model, and contact force tracking is performed, including: The deformation of the rope-traction parallel robot under contact force is determined by the nominal pose in the contact force tracking subtask. With actual pose The difference between them, and the nominal pose in the contact force tracking subtask The change is determined by the change in the nominal rope length of the rope-pulled parallel robot, and the nominal velocity in the contact force tracking subtask. Speed ​​with nominal rope length The relationship is: (13)； in, Represents the Moore-Penrose pseudoinverse of the Jacobian matrix; Based on the nominal pose in the contact force tracking subtask The relationship with the nominal rope length q allows us to write the dynamic model of equation (11) related to the contact force tracking subtask as follows: (14)； in, This represents the acceleration of the nominal pose in the contact force tracking subtask; This represents the velocity of the nominal pose in the contact force tracking subtask; Represents motion variables related to the contact force tracking subtask; The dynamic model related to the contact force tracking subtask in equation (11) is decomposed into the following nominal model and sub-deformation model, where the nominal model is: (15)； The sub-deformation model is: (16)； In the subdeformation model of equation (16), the stiffness matrix for: (17)； The relationship between the deformation and contact force of the rope-driven parallel robot is described by the sub-deformation model of equation (16). The deformation model of the contact surface is written in the following spring-damped form: (18)； in, This indicates the initial velocity of the contact force tracking subtask at the contact surface; In the above formula (18), This indicates the pose of the initial contact force tracking subtask at the contact surface; and These represent the stiffness and damping of the contact surface, respectively. The sub-deformation model parameters of the rope-traction parallel robot , and The deformation model of the contact surface in Equation (18) is obtained through offline identification, but the parameters are unknown and the shape of the contact surface is uncertain. Based on this, the deformation model of the contact surface of the rope-pulled parallel robot is written in the following transfer function form: (19)； In the above formula (19), This represents the contact force in the contact force tracking subtask; s represents the Laplace variable; This represents the nominal value of the initial contact force tracking subtask pose; total perturbation. writing: (20)； The rope-traction parallel robot adjusts the nominal rope length by controlling the motor rotation angle, and changes the nominal pose of the rope-traction parallel robot in the contact force tracking subtask according to equation (13). And control the contact force Given a desired contact force Then, the nominal pose in the contact force tracking subtask is used. As the control variable, the admittance controller based on the disturbance observer for contact force tracking is constructed as follows: (21)； in, Indicates the quality parameters of the admittance controller; Indicates the damping parameters of the admittance controller; In the above formula (21), Indicates the impact of disturbances The observed values.

6. The force-position hybrid control method for a rope-traction parallel robot according to claim 5, characterized in that, In step 4, within the trajectory tracking subtask, a sliding mode controller based on a disturbance observer is constructed and trajectory tracking is performed according to the control objective having a sliding surface form, in the following manner: The rope-traction parallel robot is subjected to... The kinematic constraints are represented by The trajectory tracking subtask for the desired trajectory can be represented as the following optimization problem: (22)； In the above formula (22), Indicates trajectory tracking error; Indicates the trajectory tracking error rate; The design parameters for the sliding mode function are represented by positive real numbers. The solution to the optimization problem of equation (22) needs to satisfy... Then the sliding mode function The convergence is defined as the control objective of the trajectory tracking subtask in the contact-rich operation task performed by the rope-pulled parallel robot. Let the output of the sliding mode controller be At this point, the dynamic model of equation (12) related to the trajectory tracking subtask can be written in the following perturbation form: (23)； In the above formula (23), This represents the total disturbance in the dynamic model; it is used to represent the total disturbance. To conduct observations, construct the following perturbation observer: (24)； In equation (24), Indicates total disturbance Observations The rate of change; Indicates the intermediate variable of torque; Indicates the gain of the perturbation observer; , These are positive real numbers that serve as parameters for the perturbation observer; The sliding mode controller based on a disturbance observer for trajectory tracking of the rope-traction parallel robot is constructed as follows: (25)； In equation (25), Output of the sliding mode controller; dynamic compensation term for: (26)； Let be the gain matrix, where It is a positive definite diagonal matrix; For the positive gain of the robust term, according to , The pattern iterates online, where t represents time. Indicate intermediate variables The rate of change Indicate intermediate variables The update step size takes the value of a positive real number; Indicates the desired acceleration; Indicates the desired speed; Representing the Jacobian matrix The rate of change of the dynamically consistent pseudo-inverse; In step 5, based on the output of the admittance controller in step 3 and the output of the sliding mode controller in step 4, and combined with the rope tension distribution algorithm based on the artificial potential field in the rope tension distribution subtask, a motor speed controller based on rope tension feedback is constructed, including: Given the nominal pose in step 3 as the contact force tracking subtask The output of the admittance controller and the output of the sliding mode controller in step 4 Afterwards, the motor speed of the rope-driven parallel robot needs to satisfy the relationship between the nominal pose and the nominal rope length in the contact force tracking subtask of equation (13), and the rope tension T needs to satisfy the following equation constraint: (27)； and the lower limit of rope tension and upper limit The following inequality constraints are defined: (28)； Based on this, the constructed motor speed controller based on rope tension feedback is as follows: (29)； In equation (29), Indicates the motor speed; This indicates the rate of change of the rope tension T; Wherein, the derivative of the rope tension T with time satisfies: (30)； In equation (30), The proportional coefficient representing rope tension control. The integral coefficient representing rope tension control; So that the rope tension satisfies the equality constraint of equation (27); To ensure that the rope tension satisfies the inequality constraint of equation (28), an artificial potential field function is introduced. The attractive items With exclusion term They are respectively: (31)； In equation (31), , Indicates positive gain; This indicates the reference tension within the upper and lower limits of the rope tension. Indicates the distance of influence of the exclusion term; The rope tension distribution based on the artificial potential field needs to satisfy the following: (32)； in, It is a positive gain; Substitute equations (30) and (32) into equation (29) to construct a motor speed controller based on rope tension feedback, and realize the motor speed control of the rope-traction parallel robot based on rope tension feedback through the constructed motor speed controller.

7. A processing device, characterized in that, include: At least one memory for storing one or more programs; At least one processor is capable of executing one or more programs stored in the memory, such that when the one or more programs are executed by the processor, the processor can perform the method according to any one of claims 1-6.

8. A readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it can implement the method described in any one of claims 1-6.

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