Tendon-based space-driven manipulator force-position hybrid control method and system

Abstract

The present application relates to the technical field of mechanical arm control, and discloses a kind of rope cluster space drive mechanical arm force-position-type fusion control method and system, including the mixed model of establishing flexible mechanical arm;Based on the mixed model, the fusion control framework of flexible mechanical arm is constructed, the force, pose and shape multi-objective cooperative control law under generalized task space is calculated, and the force, pose and shape control law are fused;The multi-objective cooperative control law after fusion is distributed to each arm rod segment, and the expected tension of the driving rope of each arm rod segment is obtained;Further refine the rope length and tension mixed controller of driving rope;Based on the speed amount of driving rope movement output by the refined rope length and tension mixed controller, the speed amount of driving rope movement is converted into the movement speed instruction of driving box, and the driving rope movement is driven to control the movement of flexible mechanical arm.The present application improves the operation performance and safety of flexible mechanical arm, avoids the slack or breakage of driving rope.

Description

Technical Field

[0001] This invention relates to the field of robotic arm control technology, specifically to a force-position-shape fusion control method and system for a rope cluster spatial drive robotic arm. Background Technology

[0002] With the continuous advancement of aerospace technology, spacecraft are operating in increasingly complex environments as they perform more intricate missions, consequently increasing the risk of malfunctions and the difficulty of maintenance. Therefore, developing highly flexible space robotic arms suitable for confined spaces has become particularly important. Rope-driven space robotic arms, with their unique structural advantages, perform exceptionally well in confined spaces. However, current rope-driven space robotic arms suffer from control errors and safety risks during operation, such as rope slackness or breakage due to excessive tension. Summary of the Invention

[0003] In view of this, the present invention provides a force-position-shape fusion control method and system for a rope cluster spatial drive robotic arm to solve the problem of how to eliminate the working error of the robotic arm and reduce safety risks.

[0004] In a first aspect, the present invention provides a force-position-shape fusion control method for a rope-driven spatial manipulator, wherein the manipulator is a flexible manipulator, the flexible manipulator comprising a drive housing and multiple arm segments connected in series; each arm segment comprising an arm and multiple center blocks connected in sequence, each arm being connected to the drive housing via multiple drive ropes; characterized in that the method comprises:

[0005] Establish a hybrid model of the flexible robotic arm;

[0006] Based on the hybrid model, a fusion control framework for the flexible robotic arm is constructed; the fusion control framework is used to perform multi-objective cooperative control of force, pose, and shape of the flexible robotic arm in a generalized task space.

[0007] Based on the aforementioned fusion control framework, the force, pose, and morphology multi-objective cooperative control law is calculated in the generalized task space, and the force, pose, and morphology control laws are fused.

[0008] The fused multi-objective cooperative control law is distributed to each of the boom segments to obtain the desired tension of the drive rope in each of the boom segments;

[0009] Based on the desired tension of the drive rope, the rope length and tension hybrid controller of the drive rope are refined;

[0010] Based on the refined rope length and tension hybrid controller outputting the speed of the driving rope, the speed of the driving rope is converted into a motion speed command for the drive box, driving the driving rope to move, thereby controlling the movement of the flexible robotic arm.

[0011] Beneficial effects: By establishing a hybrid model of the flexible robotic arm and constructing a fusion control framework for the flexible robotic arm based on the hybrid model, the flexible robotic arm can be subjected to multi-objective collaborative control of force, pose and morphology in a generalized task space. This allows the end-effector force, pose and morphological parameters of the flexible robotic arm to change according to the desired target, while avoiding slack or breakage of the drive rope.

[0012] Based on the fusion control framework, a multi-objective cooperative control law for force, pose, and form in the generalized task space is calculated and fused to achieve comprehensive control of the force, pose, and form of the flexible robotic arm. This ensures precise control of the end effector force, pose, and form of the flexible robotic arm. The fused multi-objective cooperative control law is then distributed to each segment of the flexible robotic arm to obtain the desired tension of the drive ropes for each segment. This allows for independent motion control of each segment, thereby accurately calculating the desired tension and displacement of each drive rope. This ensures that each drive rope achieves the desired motion for its segment without the risk of slack or breakage.

[0013] Based on the desired tension of the drive rope, the rope length and tension hybrid controller of the drive rope are refined. The speed of the drive rope is output through the refined rope length and tension hybrid controller, and the speed of the drive rope is converted into the speed command of the drive box to drive the flexible robotic arm. This effectively improves the operation performance and safety of the rope cluster space-driven robotic arm, and is especially suitable for precision operation tasks in confined spaces.

[0014] In one alternative implementation, establishing the hybrid model of the flexible robotic arm includes:

[0015] Establish the kinematic and static models of the flexible robotic arm.

[0016] In one optional implementation, two central blocks are provided, and three drive ropes are provided; establishing the kinematic model of the flexible robotic arm includes:

[0017] Obtain the length of each drive rope and the joint angle of each center block;

[0018] The positional and kinematic relationship between the lengths of each drive rope and the joint angles of each central block is expressed as follows:

[0019] [l1 l2 l3]=f θ-l (θ1,θ2) (1)

[0020] Where l1, l2, and l3 are the lengths of each drive rope; θ1 and θ2 are the joint angles of each center block; f θ-l For the position-level positive kinematic mapping from the center block to the driving rope;

[0021] The velocity-level kinematic expressions for the lengths of each of the drive ropes and the joint angles of each of the central blocks are as follows:

[0022]

[0023] Based on equation (2), J is obtained. seg The pseudo-inverse matrix is ​​expressed as:

[0024]

[0025] in, These are the speeds of each drive rope; These represent the joint angular velocities of each center block; J seg ∈R 2×3 The Jacobian matrix for the boom segment velocity; For J seg The pseudo-inverse matrix.

[0026] In one optional implementation, establishing the static model of the flexible robotic arm includes:

[0027] Based on equation (3) and according to the duality principle, the static equation of the driving rope is obtained, and its expression is:

[0028]

[0029] Based on equation (4) and using the pseudo-inverse method to calculate the minimum norm solution of the force of the central block to the tension of the driving rope, the expression is:

[0030]

[0031] in, For J seg The pseudo-inverse matrix; f c1 f c2 f c3 τ1 and τ2 represent the tension of each drive rope; τ1 and τ2 represent the torque of the central block, respectively. The Jacobian matrix for the force driving the rope.

[0032] In one optional implementation, the step of calculating the force, pose, and morphology multi-objective cooperative control law under the generalized task space based on the fusion control framework, and fusing the force, pose, and morphology control laws, includes:

[0033] The expression for the force, pose, and morphology multi-objective cooperative control law in the generalized task space is:

[0034]

[0035] Among them, F Fc F Pc F Ωc These are force, pose, and shape generalized control variables, respectively; e F e P e Ω These are force, pose, and shape errors, respectively. F =F ed -F e ,e P =X ed -X e e Ω =Ω d -Ω e ; These are the first derivatives of force error, pose error, and shape error, respectively; K FP K FI K FD The proportional, integral, and derivative parameters of the force controller at the end effector of the flexible robotic arm; K PP K PI K PD The proportional, integral, and derivative parameters of the end effector of the flexible robotic arm; K ΩP K ΩI K ΩD The three parameters of the flexible robotic arm's shape controller are proportional, integral, and derivative; dt is the minute change in time, and t is time.

[0036] By selecting a matrix to mix the force and pose control laws at the end effector of the flexible robotic arm, and then fusing them with the shape control law, the expression is as follows:

[0037]

[0038] Among them, F FPΩ S is the force-pose control combination matrix; S is the force control selection matrix at the end effector of the flexible robotic arm. This is the selection matrix for the end effector control of the flexible robotic arm; S1 is the first variable, S6 is the sixth variable, For the first variable, This is the 6th variable.

[0039] In one optional implementation, the expression for the desired tension of the drive rope in each of the boom segments, obtained by distributing the fused multi-objective cooperative control law to each boom segment, is as follows:

[0040]

[0041] Among them, F cd ∈R 3N S is a vector consisting of the desired tension of all drive ropes, arranged in the order of drive ropes 1-N; S is the force control selection matrix at the end of the flexible robotic arm. For the selection matrix of position control at the end effector of the flexible robotic arm; F Fc F Pc F Ωc These are force, pose, and shape generalized control variables, respectively; J L-E J is the force-pose and drive cable tension Jacobian matrix; Ω Let be the Jacobian matrix of the shape space and the driving rope tension.

[0042] In one alternative implementation, the controller that refines the rope length and tension mixture of the drive rope based on the desired tension of the drive rope includes:

[0043] Based on the desired tension of the drive rope, the length of two drive ropes is controlled, and the tension of another drive rope is controlled, thus refining the hybrid controller for the length and tension of the drive ropes; wherein, the drive rope for length control is a position-controlled drive rope, and the drive rope for tension control is a force-controlled drive rope.

[0044] For the position-controlled drive rope, the expression for the motor control torque is:

[0045]

[0046]

[0047] For the force-controlled drive rope, the expression for the motor control torque is:

[0048]

[0049] Where, Δl i To drive the change in the rope; f ci For the desired tension; k ci S is the elastic coefficient of the rope, i is the number of the driving rope; a This refers to the lead coefficient of the ball screw; Let be the desired position increment of motor j; For motor position error, The actual position increment given by the motor encoder; τ is the first derivative of the motor position error; mj1 The motor control torque for the position-controlled drive rope; τ mj2The motor controlling the torque of the force-controlled drive rope; For tensile force error, The value is measured by a tension sensor; For tension error; k Pi k Ii k Di The three parameters for driving the rope are proportional, integral, and derivative.

[0050] In one alternative implementation, after refining the rope length and tension mixture controller based on the desired tension of the drive rope, the method further includes:

[0051] Simultaneously calculate the rope length control law and tension control law for each of the drive ropes;

[0052] The motor driving torque is obtained by weighting the rope length control law and the tension control law, and the expression is:

[0053] τ mj =W i1 τ mj1 +W i2 τ mj2 i = 1, 2, 3 (14)

[0054] Where, τ mj The motor drive torque τ is the weighted sum of the rope length and tension control law. mj1 τ is the control torque for the rope length of motor j; mj2 W is the torque controlling the pulling force of motor j; i1 W i2 The weighting coefficients corresponding to the driving rope.

[0055] In one alternative implementation, it further includes:

[0056] Detect whether the flexible robotic arm has achieved the desired targets in terms of force, pose, and shape;

[0057] If the desired target is not achieved, the force-position fusion control framework of the flexible robotic arm is constructed again based on the hybrid model, and the adjustment is carried out in the next control cycle until the flexible robotic arm achieves the desired target.

[0058] Secondly, the present invention also provides a force-position-shape fusion control system for a rope bundle spatially driven robotic arm, comprising:

[0059] A module is created to build a hybrid model of the flexible robotic arm;

[0060] A construction module is used to build a fusion control framework for the flexible robotic arm based on the hybrid model; the fusion control framework is used to perform multi-objective cooperative control of force, pose, and shape of the flexible robotic arm in a generalized task space;

[0061] The first calculation module is used to calculate the force, pose, and morphology multi-objective cooperative control law in the generalized task space based on the fusion control framework, and to fuse the force, pose, and morphology control laws.

[0062] The allocation module is used to allocate the fused multi-objective cooperative control law to each boom segment to obtain the desired tension of the drive rope of each boom segment;

[0063] The second calculation module is used to refine the hybrid controller of the rope length and tension of the drive rope based on the expected tension of the drive rope.

[0064] The output module is used to output the speed of the driving rope based on the refined rope length and tension hybrid controller, and convert the speed of the driving rope into a motion speed command of the drive box to drive the driving rope to control the movement of the flexible robotic arm.

[0065] Thirdly, the present invention also provides an electronic device, comprising: a memory, a processor, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other through the communication bus;

[0066] The memory is used to store at least one executable instruction that causes the processor to perform the operation of the above-described force-position-type fusion control method for a rope cluster spatially driven robotic arm.

[0067] Fourthly, the present invention also provides a computer-readable storage medium storing at least one executable instruction that, when executed on an electronic device / rope cluster space-driven robotic arm force-position-shape fusion control system, causes the electronic device / rope cluster space-driven robotic arm force-position-shape fusion control system to perform the operation of the rope cluster space-driven robotic arm force-position-shape fusion control method as described above.

[0068] The above description is merely an overview of the technical solutions of the embodiments of the present invention. In order to better understand the technical means of the embodiments of the present invention and to implement them in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the embodiments of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0069] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0070] Figure 1 This is a flowchart illustrating the force-position-shape fusion control method for a rope cluster spatially driven robotic arm provided in an embodiment of the present invention.

[0071] Figure 2 This is a schematic diagram of the structure of the rope cluster space-driven robotic arm provided in an embodiment of the present invention;

[0072] Figure 3 This is a diagram showing the mapping relationship between the drive rope space and the joint space of the arm segment of the rope cluster space-driven robotic arm provided in an embodiment of the present invention.

[0073] Figure 4 This is a force-position-shape fusion control block diagram of a rope cluster space-driven robotic arm provided in an embodiment of the present invention;

[0074] Figure 5 This is a block diagram of the mixed control of the length and tension of the driving rope of the rope cluster space-driven robotic arm provided in the embodiment of the present invention;

[0075] Figure 6 This is a block diagram of the weighted control of the length and tension of the driving rope of the rope cluster space-driven robotic arm provided in the embodiment of the present invention;

[0076] Figure 7 This is a schematic diagram of the force-position-shape fusion control system for the rope cluster space-driven robotic arm provided in an embodiment of the present invention;

[0077] Figure 8 This is a schematic diagram of the structure of the electronic device provided in an embodiment of the present invention.

[0078] Figure label:

[0079] 100. Boom; 200. Drive motor; 300. Center block; 400. Drive box; 500. Drive rope; 600. Six-dimensional force sensor; 700. Joint angle encoder. Detailed Implementation

[0080] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0081] The design concept of the rope cluster space-driven robotic arm combines discrete rigid links, kinematic pairs, rope drive mechanisms, and rope linkage mechanisms. Through the combination of rope drive and linkage mechanisms, it achieves constant curvature bending motion of the arm segments and dexterous movement of the entire arm. Simultaneously, while maintaining motion flexibility, end-effector accuracy, and structural rigidity, it significantly reduces the number, mass, and power consumption of drive units. However, due to the over-constraint characteristics of the rope cluster drive assembly and the underdetermined nature of the static equations, there are control errors and safety risks, such as the possibility of rope slackness or excessive tightness leading to breakage.

[0082] In addition, when performing precision tasks in confined spaces, in addition to requiring the robotic arm end to meet the desired operating force and posture, the entire arm shape must also adapt to the restricted environment to ensure safety when the arm collides with the environment.

[0083] In view of this, the present invention discloses a force-position-shape fusion control method and system for a rope cluster space-driven robotic arm, which optimizes the precise operation capability of the flexible robotic arm in a confined space, while solving the problem of matching rope length and tension, avoiding the risk of rope slack or breakage, and effectively improving the operation performance and safety of the rope cluster space-driven robotic arm.

[0084] like Figure 2 As shown, the present invention provides a rope cluster space-driven robotic arm comprising: a flexible robotic arm, the flexible robotic arm including a drive box 400 and arm segments connected in series, the arm segments including arm rods 100 and a center block 300 connected in sequence, the arm rods 100 and the center block 300 in each arm segment being connected by bearings, each arm rod 100 being connected to the drive box 400 by a drive rope 500, and a six-dimensional force sensor 600 being disposed on the end arm rod 100.

[0085] In one embodiment, the flexible robotic arm includes an arm 100 and a drive housing 400. The center block 300 is a universal joint, which has two degrees of freedom with mutually perpendicular rotation axes, forming two joint angles. Each universal joint has a joint angle encoder 700 to acquire the angle information of the center block 300. Each arm 100 is connected to a drive motor 200 via three drive ropes 500. The feedback and acquisition of force, position, and shape control information are mainly achieved by acquiring the angle of the center block 300 through the joint angle encoder 700, calculating the end-effector pose and the overall arm angle, and using a six-dimensional force sensor 600 at the end-effector to provide feedback on the end-effector force and torque. For the specific structure of the flexible robotic arm, please refer to the invention patent application with application number CN202010804221.X.

[0086] The following describes a specific embodiment of the force-position-shape fusion control method for a rope bundle spatial drive robotic arm according to the present invention. Figure 1This is a flowchart illustrating a force-position-shape fusion control method for a rope-bundle spatially driven robotic arm according to an embodiment of the present invention. This specification provides the method operation steps as shown in the embodiments or flowcharts, but based on conventional or non-inventive methods, more or fewer operation steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only execution order. In actual system or server product execution, the method can be executed sequentially according to the embodiments or drawings, or in parallel (e.g., in a parallel processor or multi-threaded processing environment). Specifically, as shown... Figure 1 As shown, the method may include the following steps:

[0087] S100. Establish a hybrid model of the flexible robotic arm;

[0088] S200. Based on the hybrid model, a fusion control framework for a flexible robotic arm is constructed. The fusion control framework is used to perform multi-objective collaborative control of force, pose, and morphology of the flexible robotic arm in a generalized task space.

[0089] S300: Based on the fusion control framework, calculate the force, pose and morphology multi-objective cooperative control law in the generalized task space, and fuse the force, pose and morphology control laws;

[0090] S400: Distribute the fused multi-objective cooperative control law to each boom segment to obtain the desired tension of the drive rope of each boom segment;

[0091] S500, a hybrid controller for the length and tension of the drive rope, based on the desired tension of the drive rope;

[0092] The S600, based on the refined rope length and tension hybrid controller output, drives the speed of the rope movement. It then converts the speed of the rope movement into a speed command for the drive box, thereby driving the rope movement and controlling the movement of the flexible robotic arm.

[0093] In this embodiment, a hybrid model of the flexible robotic arm is established, and a fusion control framework for the flexible robotic arm is constructed based on the hybrid model. This enables multi-target collaborative control of force, pose, and morphology of the flexible robotic arm in a generalized task space. This allows the end-effector forces, pose, and morphological parameters of the flexible robotic arm to change according to the desired targets, while avoiding slack or breakage of the drive rope.

[0094] Based on the fusion control framework, a multi-objective cooperative control law for force, pose, and form in the generalized task space is calculated and fused to achieve comprehensive control of the force, pose, and form of the flexible robotic arm. This ensures precise control of the end effector force, pose, and form of the flexible robotic arm. The fused multi-objective cooperative control law is then distributed to each segment of the flexible robotic arm to obtain the desired tension of the drive ropes for each segment. This allows for independent motion control of each segment, thereby accurately calculating the desired tension and displacement of each drive rope. This ensures that each drive rope achieves the desired motion for its segment without the risk of slack or breakage.

[0095] Based on the desired tension of the drive rope, the rope length and tension hybrid controller of the drive rope are refined. The speed of the drive rope is output through the refined rope length and tension hybrid controller, and the speed of the drive rope is converted into the speed command of the drive box to drive the flexible robotic arm. This effectively improves the operation performance and safety of the rope cluster space-driven robotic arm, and is especially suitable for precision operation tasks in confined spaces.

[0096] like Figure 3 As shown, in one embodiment, step S100 includes: establishing a kinematic model and a static model of the flexible robotic arm. Further, establishing the kinematic model of the flexible robotic arm includes:

[0097] Obtain the length of each drive rope and the joint angle of each center block;

[0098] The positional and kinematic relationships between the lengths of each drive rope and the joint angles of each center block are expressed as follows:

[0099] [l1 l2 l3]=f θ-l (θ1,θ2) (1)

[0100] Where l1, l2, and l3 are the lengths of each drive rope; θ1 and θ2 are the joint angles of each center block; f θ-l For the position-level positive kinematic mapping from the center block to the driving rope;

[0101] The velocity-level kinematic expressions for the lengths of each drive rope and the joint angles of each center block are as follows:

[0102]

[0103] Based on equation (2), J is obtained. seg The pseudo-inverse matrix is ​​expressed as:

[0104]

[0105] in, These are the speeds of each drive rope; These represent the joint angular velocities of each center block; J seg ∈R 2×3 The Jacobian matrix for the boom segment velocity; For J seg The pseudo-inverse matrix.

[0106] Equations (1) and (2) establish the relationship between the position and velocity of the center block and the drive rope, respectively. The length and velocity of the three drive ropes can be uniquely calculated based on the position and velocity of the two joint angles of the boom segment.

[0107] When calculating the state of two joints based on the length of the three drive ropes, it is an over-constraint problem that requires solving overdetermined equations. There may be no exact solution, but there is a unique least squares solution. Therefore, the joint angular velocity obtained by solving equation (3) is the least squares solution, so as to obtain a more accurate value of the joint angular velocity.

[0108] In one embodiment, a static model of the flexible robotic arm is established, including:

[0109] Based on equation (3) and according to the duality principle, the static equation of the driving rope is obtained, and its expression is:

[0110]

[0111] Based on equation (4) and using the pseudo-inverse method to calculate the minimum norm solution of the force of the central block to the tension of the driving rope, the expression is:

[0112]

[0113] in, For J seg The pseudo-inverse matrix; f c1 f c2 f c3 τ1 and τ2 represent the tension of each drive rope; τ1 and τ2 represent the torque of the central block, respectively. The Jacobian matrix for the force driving the rope.

[0114] The torques at the two joint angles can be uniquely calculated from the tensions of the three drive ropes using the static equations of the drive ropes. Conversely, when calculating the tensions of the three drive ropes using the torques at the two joint angles, it is an under-constrained problem, requiring the solution of underdetermined equations, and there are infinitely many solutions. This means that there are infinitely many results when the force of the center block is decomposed into the tension of the drive ropes. Equation (5) can be used to find the minimum norm solution for decomposing the force of the center block into the tension of the drive ropes, so that there is only one particular solution when the force of the center block is decomposed into the tension of the drive ropes, which facilitates the control of the force on the drive ropes.

[0115] Figure 3This can be represented as the kinematic and static mapping relationship between the drive rope space and the center block space. The drive ropes possess both unidirectional over-constraint characteristics in motion transmission and infinite tension distribution. If the desired motion of the center block is achieved solely through the length, position, and velocity control of the drive ropes, errors in the control itself will cause the actual rope lengths of each drive rope to deviate from the equilibrium position and velocity equations. In other words, the actual rope lengths and velocities of the three drive ropes will not match the desired positions and velocities of the two center blocks, resulting in the center blocks failing to reach the desired position. Furthermore, the drive ropes may become slack or overly tight, potentially leading to breakage and further safety issues. Therefore, when planning and controlling the trajectory, the motion matching and tension balance of the drive ropes must be considered holistically to achieve a match between rope length and tension. This ensures precise movement of the flexible robotic arm's arm segments while preventing drive rope slackness and breakage.

[0116] like Figure 4 As shown, in one embodiment, in step S300, the expression for the force, position, and type multi-objective cooperative control law in the generalized task space is:

[0117]

[0118] Among them, F Fc F Pc F Ωc These are force, pose, and shape generalized control variables, respectively; e F e P e Ω These are force, pose, and shape errors, respectively. F =F ed -F e ,e P =X ed -X e e Ω =Ω d -Ω e ; These are the first derivatives of force error, pose error, and shape error, respectively; K FP K FI K FD The proportional, integral, and derivative parameters of the force controller at the end effector of the flexible robotic arm; K PP K PI K PD The proportional, integral, and derivative parameters of the end effector of the flexible robotic arm; K ΩP K ΩI K ΩD The three parameters of the flexible robotic arm's shape controller are proportional, integral, and derivative; dt is the minute change in time, and t is time.

[0119] By selecting a matrix to mix the force and pose control laws at the end effector of the flexible robotic arm, and then fusing them with the shape control law, the expression is as follows:

[0120]

[0121] Among them, F FPΩ S is the force-pose control combination matrix; S is the force control selection matrix at the end effector of the flexible robotic arm. This is the selection matrix for the end effector control of the flexible robotic arm; S1 is the first variable, S6 is the sixth variable, For the first variable, This is the 6th variable.

[0122] In equation (8), S can be used to... g , Let S represent the g-th variable, if S g =1, then This indicates that the g-th variable is selected for force control, but not for position control in the corresponding direction. If S g =0, then This indicates that the g-th variable was not selected for force control, and position control was performed in the corresponding direction.

[0123] In one embodiment, the expression in step S400 is:

[0124]

[0125] Among them, F cd ∈R 3N S is a vector consisting of the desired tension of all drive ropes, arranged in the order of drive ropes 1-N; S is the force control selection matrix at the end of the flexible robotic arm. For the selection matrix of position control at the end effector of the flexible robotic arm; F Fc F Pc F Ωc These are force, pose, and shape generalized control variables, respectively; J L-E J is the force-pose and drive cable tension Jacobian matrix; Ω Let be the Jacobian matrix of the shape space and the driving rope tension.

[0126] like Figure 5 As shown, in one embodiment, step S500 includes:

[0127] Based on the desired tension of the drive rope, the length of two drive ropes is controlled and the tension of another drive rope is controlled, thus refining the hybrid controller of the length and tension of the drive ropes; among them, the drive rope for length control is the position control drive rope, and the drive rope for tension control is the force control drive rope.

[0128] For a position-controlled drive rope, the expression for the motor control torque is:

[0129]

[0130]

[0131] For force-controlled drive ropes, the expression for the motor control torque is:

[0132]

[0133] Where, Δl i To drive the change in the rope; f ci For the desired tension; k ci S is the elastic coefficient of the rope, i is the number of the driving rope; a This refers to the lead coefficient of the ball screw; Let be the desired position increment of motor j; For motor position error, The actual position increment given by the motor encoder; τ is the first derivative of the motor position error; mj1 The motor control torque for the position-controlled drive rope; τ mj2 The motor controlling the torque of the force-controlled drive rope; For tensile force error, The value is measured by a tension sensor; For tension error; k Pi k Ii k Di The three parameters for driving the rope are proportional, integral, and derivative.

[0134] The refined rope length and tension controller combines the unidirectional over-constraint of the drive rope length with the infinite distribution of tension. By using the desired tension of the three drive ropes and considering the tension of each drive rope, the control mode is selected. The two drive ropes with the safest force are selected for rope length control, i.e., position control drive ropes, to ensure that the positions of the two center blocks can reach the desired positions. The other one is used for tension control to prevent the drive rope from being too loose or too tight, i.e., force control drive rope.

[0135] By setting the desired tension of the two position control drive ropes as f c1 f c2 The desired tension of the force-controlled drive rope is f. c3By considering the tensile characteristics of the drive rope, the desired tension of the position-controlled drive rope can be converted into the desired rope length increment. Then, based on the relationship between rope length and motor angle, the desired motor angle increment is obtained. Finally, PID (proportional-integral-derivative) control is applied to the drive motor according to the desired motor angle increment. For the force-controlled drive rope, a PID control law is directly designed for the desired tension, thereby generating the motor control torque. By applying corresponding control modes to the position-controlled and force-controlled drive ropes respectively, the control method is simple, the computational load is small, and it can ensure the positional accuracy of the center block while avoiding the drive rope being too slack or too tight.

[0136] like Figure 6 As shown, in one embodiment, after step S500, the method further includes:

[0137] Simultaneously calculate the rope length control law and tension control law for each drive rope;

[0138] By weighting the rope length control law and the tension control law, the motor driving torque is obtained, and its expression is:

[0139] τ mh =W 3m τ jim +W i2 τ mj2 i = 1, 2, 3 (14)

[0140] Where, τ mj The motor drive torque τ is the weighted sum of the rope length and tension control law. mj1 τ is the control torque for the rope length of motor j; mj2 W is the torque controlling the pulling force of motor j; i1 W i2 The weighting coefficients corresponding to the driving rope.

[0141] The weighting coefficients of each drive rope are determined by the control mode decision module, and W is satisfied. i1 +W i2 =1. When W i1 =1, W i2 When W = 0, it indicates that the drive rope only controls the rope length; when W = 0, it indicates that the drive rope only controls the rope length. i1 =0, W i2 When W = 1, it indicates that the drive rope only performs tension control; when W = 1, it indicates that the drive rope only performs tension control. i1 and W i2 When neither value is 0, it indicates that the drive rope simultaneously controls both rope length and tension; different weight values ​​can meet different control requirements. i1 W i2It can be obtained according to the actual situation during actual use. By designing rope length and tension control laws for each drive rope simultaneously, and using the weighted sum of the calculated results as the driving torque of the motor, it can effectively avoid the situation where the position control and force control modes are repeatedly switched, which may lead to uneven motion or even oscillation.

[0142] In one embodiment, it further includes:

[0143] To determine whether the flexible robotic arm has achieved the desired force, pose, and shape objectives;

[0144] If the desired target is not achieved, the force-position fusion control framework for the flexible robotic arm is reconstructed based on the hybrid model, and adjustments are made for the next control cycle until the flexible robotic arm achieves the desired target.

[0145] In this embodiment, the system continuously detects whether the operating force, pose, and shape of the flexible robotic arm have reached the desired position. When the flexible robotic arm has not reached the desired position, the system returns to step S200 and repeats steps S200 to S500 to complete the adjustment of the next control cycle until the flexible robotic arm reaches the desired position.

[0146] This invention also provides a force-position-shape fusion control system for a rope bundle spatially driven robotic arm. Figure 7 This is a schematic diagram of an embodiment of the force-position-shape fusion control system for a rope cluster space-driven robotic arm provided in this invention. Figure 7 As shown, the system includes:

[0147] Create module 1010 to build a hybrid model of the flexible robotic arm;

[0148] Module 1020 is used to build a fusion control framework for a flexible robotic arm based on a hybrid model. The fusion control framework is used to perform multi-objective collaborative control of force, pose, and morphology of the flexible robotic arm in a generalized task space.

[0149] The first calculation module 1030 is used to calculate the force, pose and morphology multi-objective cooperative control law under the generalized task space based on the fusion control framework, and to fuse the force, pose and morphology control laws.

[0150] The allocation module 1040 is used to distribute the fused multi-objective cooperative control law to each boom segment, obtaining the desired tension of the drive rope in each boom segment, expressed as:

[0151]

[0152] Among them, F cd ∈R 3NS is a vector consisting of the desired tension of all drive ropes, arranged in the order of drive ropes 1-N; S is the force control selection matrix at the end of the flexible robotic arm. For the selection matrix of position control at the end effector of the flexible robotic arm; F Fc F Pc F Ωc These are force, pose, and shape generalized control variables, respectively; J L-E J is the force-pose and drive cable tension Jacobian matrix; Ω The form space and the Jacobian matrix of the driving rope tension;

[0153] The second calculation module 1050 is used to refine the hybrid controller of the rope length and tension of the drive rope based on the expected tension of the drive rope.

[0154] The output module 1060 is used to output the speed of the driving rope based on the refined rope length and tension hybrid controller, and convert the speed of the driving rope into the motion speed command of the drive box to drive the driving rope to control the movement of the flexible robotic arm.

[0155] In one embodiment, the establishment module 1010 includes:

[0156] Establish a submodule to create the kinematic and static models of the flexible robotic arm.

[0157] In one embodiment, establishing a submodule includes:

[0158] The acquisition unit is used to acquire the length of each drive rope and the joint angle of each center block;

[0159] The positional and kinematic relationships between the lengths of each drive rope and the joint angles of each center block are expressed as follows:

[0160] [l1 l2 l3]=f θ-l (θ1,θ2) (1)

[0161] Where l1, l2, and l3 are the lengths of each drive rope; θ1 and θ2 are the joint angles of each center block; f θ-l For the position-level positive kinematic mapping from the center block to the driving rope;

[0162] The velocity-level kinematic expressions for the lengths of each drive rope and the joint angles of each center block are as follows:

[0163]

[0164] in, These are the speeds of each drive rope; These are the joint angular velocities of the center block; J seg ∈R 2×3Let be the Jacobian matrix of the boom segment velocity.

[0165] In one embodiment, the establishment submodule is also used to obtain J based on equation (2). seg The pseudo-inverse matrix is ​​expressed as:

[0166]

[0167] Based on equation (3) and according to the duality principle, the static equation of the driving rope is obtained, and its expression is:

[0168]

[0169] Based on equation (4) and using the pseudo-inverse method to calculate the minimum norm solution of the force of the central block to the tension of the driving rope, the expression is:

[0170]

[0171] in, For J seg The pseudo-inverse matrix; f c1 f c2 f c3 τ1 and τ2 represent the tension of each drive rope; τ1 and τ2 represent the torque of the central block, respectively. The Jacobian matrix for the force driving the rope.

[0172] In one embodiment, the first computing module 1030 includes:

[0173] The first calculation submodule is used to calculate the expression of the force, pose, and morphology multi-objective cooperative control law in the generalized task space.

[0174]

[0175] Among them, F Fc F Pc F Ωc These are force, pose, and shape generalized control variables, respectively; e F e P e Ω These are force, pose, and shape errors, respectively. F =F ed -F e ,e P =X ed -X e e Ω =Ω d -Ω e ; These are the first derivatives of force error, pose error, and shape error, respectively; K FP KFI K FD The proportional, integral, and derivative parameters of the force controller at the end effector of the flexible robotic arm; K PP K PI K PD The proportional, integral, and derivative parameters of the end effector of the flexible robotic arm; K ΩP K ΩI K ΩD The three parameters of the flexible robotic arm's shape controller are proportional, integral, and derivative; dt is the minute change in time, and t is time.

[0176] By selecting a matrix to mix the force and pose control laws at the end effector of the flexible robotic arm, and then fusing them with the shape control law, the expression is as follows:

[0177]

[0178] Among them, F FPΩ S is the force-pose control combination matrix; S is the force control selection matrix at the end effector of the flexible robotic arm. This is the selection matrix for the end effector control of the flexible robotic arm; S1 is the first variable, S6 is the sixth variable, For the first variable, This is the 6th variable.

[0179] In one embodiment, the second calculation module 1050 is further configured to control the length of two drive ropes and control the tension of another drive rope based on the desired tension of the drive rope, thereby refining the hybrid controller for the length and tension of the drive ropes; wherein the drive rope for length control is a position-controlled drive rope, and the drive rope for tension control is a force-controlled drive rope.

[0180] For a position-controlled drive rope, the expression for the motor control torque is:

[0181]

[0182]

[0183] For force-controlled drive ropes, the expression for the motor control torque is:

[0184]

[0185] Where, Δl i To drive the change in the rope; f ci For the desired tension; k ci S is the elastic coefficient of the rope, i is the number of the driving rope; a Δθ is the lead coefficient of the ball screw. mj Let be the desired position increment of motor j; For motor position error, The actual position increment given by the motor encoder; τ is the first derivative of the motor position error; mj1 The motor control torque for the position-controlled drive rope; τ mj2 The motor controlling the torque of the force-controlled drive rope; For tensile force error, The value is measured by a tension sensor; For tension error; k Pi k Ii k Di The three parameters for driving the rope are proportional, integral, and derivative.

[0186] In one embodiment, it further includes:

[0187] The third calculation module is used to simultaneously calculate the rope length control law and tension control law for each drive rope;

[0188] By weighting the rope length control law and the tension control law, the motor driving torque is obtained, and its expression is:

[0189] τ mj =W i1 τ mj1 +W i2 τ mj2 i = 1, 2, 3 (14)

[0190] Where, τ mj The motor drive torque τ is the weighted sum of the rope length and tension control law. mj1 τ is the control torque for the rope length of motor j; mj2 W is the torque controlling the pulling force of motor j; i1 W i2 The weighting coefficients corresponding to the driving rope.

[0191] In one embodiment, it further includes:

[0192] The detection module is used to detect whether the flexible robotic arm has achieved the desired targets in terms of force, pose, and shape.

[0193] If the desired target is not achieved, the force-position fusion control framework for the flexible robotic arm is reconstructed based on the hybrid model, and adjustments are made for the next control cycle until the flexible robotic arm achieves the desired target.

[0194] The system and method embodiments in this application are based on the same application concept.

[0195] Figure 8 The diagram shows a structural schematic of an embodiment of an electronic device provided by the present invention. The specific embodiments of the present invention do not limit the specific implementation of the electronic device.

[0196] like Figure 8 As shown, the electronic device may include: a processor 502, a communications interface 504, a memory 506, and a communications bus 508.

[0197] The processor 502, communication interface 504, and memory 506 communicate with each other via communication bus 508. Communication interface 504 is used to communicate with other network elements, such as clients or other servers. The processor 502 executes program 510, specifically performing the relevant steps described in the embodiment of the force-position-shape fusion control method for rope cluster space-driven robotic arms.

[0198] Specifically, program 510 may include program code, which includes computer-executable instructions.

[0199] Processor 502 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention. The electronic device may include one or more processors of the same type, such as one or more CPUs; or it may include processors of different types, such as one or more CPUs and one or more ASICs.

[0200] Memory 506 is used to store program 510. Memory 506 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0201] Specifically, program 510 can be called by processor 502 to cause electronic devices to execute the relevant steps in the above embodiment of the force-position-type fusion control method for rope cluster space-driven robotic arms.

[0202] Those skilled in the art will understand that Figure 8 The structure shown is for illustrative purposes only and does not limit the structure of the aforementioned device. For example, electronic devices may also include components that are more... Figure 8 The more or fewer components shown, or having the same Figure 8 The different configurations shown.

[0203] This invention provides a computer-readable storage medium storing at least one executable instruction. When the executable instruction is executed on an electronic device / rope cluster space-driven robotic arm force-position-shape fusion control system, the electronic device / rope cluster space-driven robotic arm force-position-shape fusion control system performs the rope cluster space-driven robotic arm force-position-shape fusion control method in any of the above method embodiments.

[0204] The algorithms or displays provided herein are not inherently related to any particular computer, virtual system, or other device. Furthermore, the embodiments of this invention are not directed to any particular programming language.

[0205] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. Similarly, for the sake of brevity and to aid in understanding one or more aspects of the invention, in the description of exemplary embodiments of the invention above, various features of the embodiments are sometimes grouped together in a single embodiment, figure, or description thereof. The claims, which follow the detailed description, are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0206] Those skilled in the art will understand that the modules in the device of the embodiment can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiment can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components, except that at least some of such features and / or processes or units are mutually exclusive.

[0207] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several systems, several of these systems may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be construed as limiting the order of execution.

Claims

1. A force-position-shape fusion control method for a rope-driven spatial manipulator, wherein the manipulator is a flexible manipulator, the flexible manipulator comprising a drive housing and multiple arm segments connected in series; each arm segment comprising an arm rod and multiple center blocks connected in sequence, each arm rod being connected to the drive housing via multiple drive ropes; characterized in that, The method includes: Establish a hybrid model of the flexible robotic arm; Based on the hybrid model, a fusion control framework for the flexible robotic arm is constructed; the fusion control framework is used to perform multi-objective cooperative control of force, pose, and shape of the flexible robotic arm in a generalized task space. Based on the aforementioned fusion control framework, the force, pose, and morphology multi-objective cooperative control law is calculated in the generalized task space, and the force, pose, and morphology control laws are fused. The fused multi-objective cooperative control law is distributed to each of the boom segments to obtain the desired tension of the drive rope in each of the boom segments; Based on the desired tension of the drive rope, the rope length and tension hybrid controller of the drive rope are refined; Based on the refined rope length and tension hybrid controller outputting the speed of the driving rope, the speed of the driving rope is converted into a speed command for the drive box, driving the driving rope to move, thereby controlling the movement of the flexible robotic arm. The controller that refines the rope length and tension mixture of the drive rope based on the desired tension of the drive rope includes: Based on the desired tension of the drive rope, the length of two drive ropes is controlled, and the tension of another drive rope is controlled, thus refining the hybrid controller for the length and tension of the drive ropes; wherein, the drive rope for length control is a position-controlled drive rope, and the drive rope for tension control is a force-controlled drive rope. For the position-controlled drive rope, the expression for the motor control torque is: （10） （11） （12） For the force-controlled drive rope, the expression for the motor control torque is: （13） in, To drive the change in rope length; The desired tensile force; is the elastic coefficient of the rope, and i is the number of the driving rope; This refers to the lead coefficient of the ball screw; Let be the desired position increment of motor j; For motor position error, The actual position increment given by the motor encoder; The first derivative of the motor position error; The motor control torque for the position-controlled drive rope; The motor controlling the force of the force-controlled drive rope; For tensile force error, The value is measured by a tension sensor; This is for tensile force error; , , The three parameters for driving the rope are proportional, integral, and derivative.

2. The force-position-shape fusion control method for a rope bundle spatial driven robotic arm according to claim 1, characterized in that, The establishment of the hybrid model of the flexible robotic arm includes: Establish the kinematic and static models of the flexible robotic arm.

3. The force-position-shape fusion control method for a rope bundle spatial driven robotic arm according to claim 2, characterized in that, Two central blocks are provided, and three drive ropes are provided; establishing the kinematic model of the flexible robotic arm includes: Obtain the length of each drive rope and the joint angle of each center block; The positional and kinematic relationship between the lengths of each drive rope and the joint angles of each central block is expressed as follows: （1） in, , , These are the lengths of each drive rope; , These are the joint angles of each central block; For the position-level positive kinematic mapping from the center block to the driving rope; The velocity-level kinematic expressions for the lengths of each of the drive ropes and the joint angles of each of the central blocks are as follows: （2） Based on equation (2), we obtain The pseudo-inverse matrix is ​​expressed as: （3） in, , , These are the speeds of each drive rope; , These are the joint angular velocities of each center block; The Jacobian matrix for the boom segment velocity; for The pseudo-inverse matrix.

4. The force-position-shape fusion control method for a rope bundle spatial driven robotic arm according to claim 3, characterized in that, The process of establishing the static model of the flexible robotic arm includes: Based on equation (3) and according to the duality principle, the static equation of the driving rope is obtained, and its expression is: （4） Based on equation (4) and using the pseudo-inverse method to calculate the minimum norm solution of the force of the central block to the tension of the driving rope, the expression is: （5） in, , , These represent the tension in each drive rope; , These are the torques of the central block; The Jacobian matrix for the driving rope.

5. The force-position-shape fusion control method for a rope bundle spatial driven robotic arm according to claim 1, characterized in that, The process, based on the fusion control framework, calculates the force, pose, and morphology multi-objective cooperative control law in the generalized task space, and fuses the force, pose, and morphology control laws, including: The expression for the force, pose, and morphology multi-objective cooperative control law in the generalized task space is: （6） in, , , These are force, pose, and form generalized control quantities, respectively. , , These are force, pose, and shape errors, respectively. , , ; , , These are the first derivatives of force error, pose error, and shape error, respectively. , , The proportional, integral, and derivative parameters are used for the force controller at the end effector of the flexible robotic arm. , , The proportional, integral, and derivative parameters are used for the end effector of the flexible robotic arm's pose controller. , , The three parameters of the flexible robotic arm's shape controller are proportional, integral, and derivative; dt is the minute change in time, and t is time. By selecting a matrix to mix the force and pose control laws at the end effector of the flexible robotic arm, and then fusing them with the shape control law, the expression is as follows: （7） （8） in, This is the force-pose control combination matrix; Select a matrix for force control at the end effector of a flexible robotic arm; Select matrix for end-effector positioning control of flexible robotic arms; For the first variable, For the 6th variable, For the first variable, This is the 6th variable.

6. The force-position-shape fusion control method for a rope bundle spatial driven robotic arm according to claim 1, characterized in that, The expression for the desired tension of the drive rope in each boom segment, obtained by distributing the fused multi-objective cooperative control law to each boom segment, is as follows: （9） in, This is a vector consisting of the desired tensions of all driving ropes, arranged in the order of driving ropes 1-N; Select a matrix for force control at the end effector of a flexible robotic arm; Select matrix for end-effector positioning control of flexible robotic arms; , , These are force, pose, and form generalized control quantities, respectively. The force-pose and drive cable tension Jacobian matrix; Let be the Jacobian matrix of the shape space and the driving rope tension.

7. The force-position-shape fusion control method for a rope bundle spatial driven robotic arm according to claim 1, characterized in that, After refining the rope length and tension hybrid controller based on the desired tension of the drive rope, the system further includes: Simultaneously calculate the rope length control law and tension control law for each of the drive ropes; The motor driving torque is obtained by weighting the rope length control law and the tension control law, and the expression is: （14） in, The motor drive torque is a weighted sum of the rope length and tension control law; The control torque for motor j is the rope length. The torque is the control torque for the pulling force of motor j; , The weighting coefficients corresponding to the driving rope.

8. The force-position-shape fusion control method for a rope bundle spatial driven robotic arm according to claim 1, characterized in that, Also includes: Detect whether the flexible robotic arm has achieved the desired targets in terms of force, pose, and shape; If the desired target is not achieved, the force-position fusion control framework of the flexible robotic arm is constructed again based on the hybrid model, and the adjustment is carried out in the next control cycle until the flexible robotic arm achieves the desired target.

9. A force-position-shape fusion control system for a rope bundle spatially driven robotic arm, employing the force-position-shape fusion control method for a rope bundle spatially driven robotic arm as described in claim 1, characterized in that... include: A module is created to build a hybrid model of the flexible robotic arm; A building module is used to construct the fusion control framework of the flexible robotic arm based on the hybrid model; The fusion control framework is used to perform multi-objective collaborative control of force, pose, and shape of the flexible robotic arm in a generalized task space. The first calculation module is used to calculate the force, pose, and morphology multi-objective cooperative control law in the generalized task space based on the fusion control framework, and to fuse the force, pose, and morphology control laws. The allocation module is used to allocate the fused multi-objective cooperative control law to each boom segment to obtain the desired tension of the drive rope of each boom segment; The second calculation module is used to refine the hybrid controller of the rope length and tension of the drive rope based on the expected tension of the drive rope. The output module is used to output the speed of the driving rope based on the refined rope length and tension hybrid controller, and convert the speed of the driving rope into the speed command of the drive box to drive the driving rope to control the movement of the flexible robotic arm. The second calculation module is also used to control the length of two drive ropes and control the tension of another drive rope based on the expected tension of the drive rope, thereby refining the hybrid controller of the length and tension of the drive rope; wherein the drive rope for length control is a position-controlled drive rope and the drive rope for tension control is a force-controlled drive rope. For the position-controlled drive rope, the expression for the motor control torque is: （10） （11） （12） For the force-controlled drive rope, the expression for the motor control torque is: （13） in, To drive the change in rope length; The desired tensile force; is the elastic coefficient of the rope, and i is the number of the driving rope; This refers to the lead coefficient of the ball screw; Let be the desired position increment of motor j; For motor position error, The actual position increment given by the motor encoder; The first derivative of the motor position error; The motor control torque for the position-controlled drive rope; The motor controlling the force of the force-controlled drive rope; For tensile force error, The value is measured by a tension sensor; This is for tensile force error; , , The three parameters for driving the rope are proportional, integral, and derivative.

Images