Tactile servo control method for flexible wire routing operations

Abstract

A tactile servo control method for flexible wire routing operations belongs to the field of tactile sensing and robot control. It solves the problems of the existing flexible wire control method implemented by tactile sensors based on the visual tactile principle, such as low sensor life, complex calculations, inability to obtain direct force information, and unsuitability for complex industrial scenarios. The method of the present invention divides the routing task into three stages: grasping stage, calibration stage, and wire drawing stage. The entire control method relies entirely on tactile perception and can complete the task operation without visual feedback; the three-dimensional force tactile sensor array is divided into two areas: the grasping perception area and the wire falling perception area. The utilization of the tangential force and normal force in the three-dimensional force array information is more perfect, and the control of the robot arm and the gripper is more comprehensive and accurate. It has both force control and posture control, making the control effect smoother and ensuring that the wire will not be damaged while completing the task. It is mainly used for flexible wire routing operations.

Description

Technical Field

[0001] The present invention belongs to the field of tactile sensing and robot control, and in particular relates to a tactile perception-based collaborative control method of a robotic arm and a gripper for flexible wire manipulation. Background Art

[0002] Flexible wires (e.g., cables) are a typical example of deformable linear objects and are widely used. However, traditional rigid control methods often struggle to cope with the nonlinear deformation and uncertainty of wires during operation. This difficulty stems from their high flexibility, making them difficult to model.

[0003] Currently, most industries use manual methods or specific fixtures to operate flexible wires, which are not universal and have poor flexibility. Flexible wire control methods can be roughly divided into two categories:

[0004] The first type is to establish a mechanical model for the flexible wire. The advantage of this method is that the deformation of the flexible wire can be directly calculated through the model. The disadvantage is that the modeling process is relatively complicated, the generalization is insufficient, and the scalability is poor.

[0005] The second category is model-free control methods. Most of these methods use visual sensors as an aid and operate flexible wires through machine vision-related technologies. The advantage of this type of method is that it does not require the establishment of a complex mechanical model and has certain generalization and scalability. The disadvantage is that the accuracy is poorer than the first type of method, there is no direct force feedback information, and the effect is poor for cases with large deformation, especially for scenes with blocked vision. When servo control is performed on the flexible wire, the accuracy of recognizing the hanging shape of the flexible wire is poor, resulting in the robot arm's motion trajectory being unable to accurately follow the wire shape, resulting in poor control effect.

[0006] In recent years, people have gradually paid attention to the application of tactile perception in robot control. As a type of tactile sensor, visual tactile sensors have been widely studied. The current mainstream visual tactile sensors are composed of three components in structural design: a contact colloid layer, a light source structure, and a camera imaging system. They use methods such as photometric stereo algorithms to reconstruct the contact surface geometry to determine the contact shape, and use elastic theory mapping modeling or learning methods to estimate force. This method is computationally complex and cannot obtain direct and effective release force information. The colloid layer is easily damaged, the sensor life is short, and the cost is high, making it unsuitable for industrial scenarios.

[0007] In the complex 3C product manufacturing environment, the manipulation of flexible wires requires precise force control and position adjustment. Therefore, traditional visual servo control often suffers from poor control effectiveness due to a lack of force feedback information. In scenarios where vision is blocked, the servo control of flexible wires is inaccurate in recognizing the falling shape of the flexible wires, resulting in the robot arm's motion trajectory being unable to accurately follow the wire shape, resulting in poor control effectiveness. Tactile sensors based on visual tactile principles are unsuitable for complex industrial scenarios due to their easily damaged colloid layer, short lifespan, complex calculations, inability to obtain direct force information, and lack of suitability. Therefore, the above issues urgently need to be addressed. Summary of the Invention

[0008] The purpose of the present invention is to solve the problems of the existing flexible wire control method implemented by tactile sensors based on the visual-tactile principle, such as short sensor life, complex calculations, inability to obtain direct force information, and unsuitability for complex industrial scenarios. The present invention provides a tactile servo control method for flexible wire wiring operations.

[0009] A tactile servo control method for flexible wire routing operations is based on three-dimensional force tactile sensor arrays installed within the upper and lower gripping surfaces of a two-finger gripper at the end of a robotic arm, and a flexible wire with one end fixed and the other free. The two three-dimensional force tactile sensor arrays are arranged relative to each other and partially overlap. The overlapping and non-overlapping areas of each three-dimensional force tactile sensor array are rectangular arrays, and the two are defined as a grasping sensing area and a wire falling sensing area, respectively. The method includes the following steps:

[0010] Grasping stage: The flexible wire is gripped by a two-finger gripper, and the distance L1 between the current gripping position and the nearest fixed end of the flexible wire is recorded;

[0011] Calibration phase:

[0012] The tangential force distribution data sensed by the gripping sensing area is extracted in real time to control the gripping force of the two-finger gripper, so that the friction between the two-finger gripper and the flexible wire is within a preset range.

[0013] Extract the normal force distribution data sensed by the gripping sensing area, and control the position of the two-finger gripper during its movement along the length of the flexible wire. After a section of the flexible wire within the gripping sensing area is effectively contacted by the two-finger gripper, record the movement distance L2 of the two-finger gripper along the length of the flexible wire during the calibration phase, as well as the drooping deviation of the flexible wire profile sensed by the wire drooping sensing area.

[0014] Threading stage:

[0015] The tangential force distribution data sensed by the gripping sensing area is extracted in real time to control the gripping force of the two-finger gripper, so that the friction between the two-finger gripper and the flexible wire is within a preset range.

[0016] While maintaining effective contact between a section of flexible wire in the grasping sensing area and the two-finger gripper, the two-finger gripper is controlled to perform a wire-straightening operation along the flexible wire's contour in three-dimensional space according to the contour drop deviation. The wire-straightening operation is stopped when the wire length reaches the length L-L1-L2. After increasing the clamping force of the two-finger gripper to clamp the wire, the robotic arm is controlled to move the flexible wire to the target position and then lay it out. L is the total length of the wire required for the current target position.

[0017] The grasping stage, calibration stage and wiring stage are repeated in sequence until all target positions are arranged and the wiring of the flexible wire is completed.

[0018] Preferably, the normal force distribution data sensed by the gripping sensing area is extracted, and the posture of the two-finger gripper during the movement along the length direction of the flexible wire is controlled so that a section of the flexible wire in the gripping sensing area is effectively contacted with the two-finger gripper. The implementation method includes:

[0019] S11. In the direction of the two-finger gripper toward the flexible wire, establish a spatial coordinate system for the robotic arm with the midpoint of the outer wide side of the grasping sensing area of ​​each three-dimensional force tactile sensor array as the origin, the direction pointing toward the wire falling sensing area in the plane of the grasping sensing area as the x-axis direction, the direction pointing forward as the y-axis direction, and the direction perpendicular to the plane of the x-axis and y-axis and pointing downward as the z-axis direction;

[0020] S12, converting the normal force distribution data sensed by the grasping sensing area of ​​each three-dimensional force tactile sensor array into a grayscale image, and analyzing the grayscale image using an image moment analysis method to obtain the center of mass coordinates and principal component directions;

[0021] According to the coordinates of the center of mass, determine the position deviation Δx of the center of mass relative to the origin in the x-axis direction and the position deviation Δy in the y-axis direction;

[0022] The angle between the principal component direction and the x-axis direction is taken as the principal component offset angle Δα;

[0023] S13, the position deviation Δx in the x-axis direction, the position deviation Δy in the y-axis direction, and the principal component offset angle Δα corresponding to the two three-dimensional force tactile sensor arrays are averaged to obtain the position deviation mean in the x-axis direction. Position deviation in the y-axis direction and principal component offset angle

[0024] S14, during the movement of the two-finger gripper along the length direction of the flexible wire, according to the current and The value of adjusts the posture of the two-finger gripper so that and approaches 0 and satisfies When , it is determined that a section of flexible wire in the grasping sensing area is in effective contact with the two-finger gripper, where δ1 and δ2 are both positive numbers.

[0025] Preferably, in step S14, according to the current and The value of is used to adjust the posture of the two-finger gripper as follows:

[0026] When , the two-finger gripper is controlled to move along the positive direction of the x-axis, otherwise, the two-finger gripper is controlled to move along the negative direction of the x-axis;

[0027] When , the two-finger gripper is controlled to move along the positive direction of the y-axis, otherwise, the two-finger gripper is controlled to move along the negative direction of the y-axis;

[0028] When the two-finger gripper is in the state of rotation, the two-finger gripper is controlled to rotate clockwise around the z-axis; otherwise, the two-finger gripper is controlled to rotate counterclockwise around the z-axis.

[0029] Preferably, the method for sensing the drooping deviation of the flexible wire profile through the wire drooping sensing area is as follows:

[0030] S21, calculate F according to the normal force distribution data sensed by the wire drop sensing area of ​​each three-dimensional force tactile sensing array θ1 and F θ2 ; F θ1 and F θ2 is the resultant force in the normal direction of all the contact points in the wire drop sensing area of ​​the three-dimensional force tactile sensing array located below and above, and F θ1 and F θ2 All are scalar;

[0031] S22, calculate the profile drop deviation ΔF=F θ1 -F θ2 .

[0032] Preferably, the method for controlling the two-finger gripper to perform the wire straightening operation along the flexible wire profile falling direction in three-dimensional space according to the profile falling deviation is as follows:

[0033] When ΔF>0, the two-finger gripper is controlled to move along the positive direction of the z-axis of the robot arm's spatial coordinate system and rotate clockwise around the y-axis;

[0034] When ΔF<0, the two-finger gripper is controlled to move along the negative direction of the z-axis of the robot arm's spatial coordinate system and rotate counterclockwise around the y-axis;

[0035] Among them, the spatial coordinate system of the robotic arm is a coordinate system established in the direction of the two-finger gripper toward the flexible wire, with the midpoint of the outer wide side of the grasping sensing area of ​​each three-dimensional force tactile sensing array as the origin, the direction pointing to the wire falling sensing area in the plane where the grasping sensing area is located as the x-axis direction, the direction pointing forward as the y-axis direction, and the direction perpendicular to the plane where the x-axis and y-axis are located and pointing downward as the z-axis direction.

[0036] Preferably, when wiring for different target positions, the values ​​of L corresponding to each target position are the same or different, and the values ​​of L1 corresponding to each target position are the same, and the values ​​of L2 corresponding to each target position are the same or different.

[0037] Preferably, the area ratio of the overlapping area to the non-overlapping area on each three-dimensional force tactile sensing array is 3:1 or 2:1.

[0038] Preferably, the three-dimensional force tactile sensing array is implemented using a capacitive three-dimensional force tactile sensing array.

[0039] A tactile servo control device for flexible wire routing operations includes a storage device, a processor, and a computer program stored in the storage device and runnable on the processor. The processor executes the computer program to implement the tactile servo control method for flexible wire routing operations.

[0040] A computer-readable storage device stores a computer program, and when the computer program is executed, the tactile servo control method for flexible wire wiring operations is implemented.

[0041] Advantages of the present invention:

[0042] The method of the present invention divides the wiring task into three stages: grasping, calibration, and winding, making the operation accurate and efficient. The entire control method relies entirely on tactile perception and can complete the task operation without visual feedback.

[0043] The 3D force tactile sensor array can directly obtain effective 3D force information, with fast calculation, low sensor cost and long life. It can realize automated operation of various types of wires in dark environments, confined spaces or under visual obstruction, and can efficiently complete tasks such as arranging wires in 3D space without damaging the wires due to excessive force.

[0044] In addition, the three-dimensional force tactile sensing array is divided into two areas: the grasping sensing area and the wire falling sensing area. The utilization of the tangential force and normal force in the three-dimensional force array information is more perfect. The tangential force is used to control the opening and closing of the gripper, that is, the contact force, to ensure that the force is moderate during the wire contour following process, and the wire pulling is gentle without damaging the wire. The control of the robotic arm and gripper is more comprehensive and accurate, with both force control and posture control, making the control effect smoother. It does not rely on visual sensors to perceive linear changes and realize wire-straightening operations, ensuring that the wire will not be damaged while completing the task.

[0045] The present invention is more suitable for complex industrial scenarios, and can realize the tasks of grabbing, following, and routing flexible wires, and has a certain inspiration and optimization effect on the industrial assembly of deformable linear objects. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a flow chart of the tactile servo control method for flexible wire operation according to the present invention;

[0047] Figure 2 is a diagram showing the relative positions of the flexible wire 2 and the target position 3 after wiring is completed;

[0048] Figure 3 It is a schematic diagram of the three-dimensional structure of the two-finger gripper;

[0049] Figure 4 is a top view of the two-finger gripper;

[0050] Figure 5 is a positional relationship diagram of the grasping sensing area 1-1 and the wire dropping sensing area 1-2 in the three-dimensional force tactile sensing array 1;

[0051] Figure 6 Schematic diagram of the contact between each tactile sensing unit and the wire in the grip sensing area 1-1;

[0052] Figure 7 This is a diagram showing the relative position relationship between the three-dimensional force tactile sensor array 1 and the flexible wire 2 installed in the upper and lower clamping surfaces of the two-finger gripper. DETAILED DESCRIPTION

[0053] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0054] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0055] Research on tactile servo control mainly focuses on the following aspects: first, the design of control strategy, how to use tactile information to adjust the operation trajectory and applied force in real time to ensure the precise layout and installation of wires; second, the real-time and stability issues of the system. In a complex and changing operating environment, how to ensure the real-time nature of tactile feedback and the robustness of the control strategy are still difficult research points.

[0056] Specific implementation method 1. Figures 1 to 5 This embodiment describes a tactile servo control method for flexible wire routing operations. The method is based on a three-dimensional force tactile sensor array 1 installed within the upper and lower clamping surfaces of a two-finger gripper at the end of a robotic arm, and a flexible wire 2 with one end fixed and the other end free. The two three-dimensional force tactile sensor arrays 1 are arranged relative to each other and partially overlap. The overlapping area and non-overlapping area of ​​each three-dimensional force tactile sensor array 1 are rectangular arrays, and the two are respectively defined as a grasping sensing area 1-1 and a wire falling sensing area 1-2. The method includes the following steps:

[0057] Grasping stage: The flexible wire 2 is gripped by a two-finger gripper, and the distance L1 between the current gripping position and the nearest fixed end of the flexible wire 2 is recorded;

[0058] Calibration phase:

[0059] Extract the tangential force distribution data sensed by the grip sensing area 1-1 in real time, and control the gripping force of the two-finger gripper so that the friction force between the two-finger gripper and the flexible wire 2 is within a preset range;

[0060] Extract the normal force distribution data sensed by the grasping sensing area 1-1, control the posture of the two-finger gripper during the movement along the length direction of the flexible wire 2, and make a section of the flexible wire 2 in the grasping sensing area 1-1 effectively contact the two-finger gripper. At this time, record the movement distance L2 of the two-finger gripper along the length direction of the flexible wire 2 during the calibration phase, as well as the contour drooping deviation of the flexible wire 2 sensed by the wire drooping sensing area 1-2, and participate in the calibration. Figure 7 ;

[0061] Threading stage:

[0062] Extract the tangential force distribution data sensed by the grip sensing area 1-1 in real time, and control the gripping force of the two-finger gripper so that the friction force between the two-finger gripper and the flexible wire 2 is within a preset range;

[0063] While maintaining effective contact between a section of flexible wire 2 in the grasping sensing area 1-1 and the two-finger gripper, the two-finger gripper is controlled to perform a wire-straightening operation along the contour of the flexible wire 2 in three-dimensional space according to the contour-straightening deviation. The wire-straightening operation is stopped after the wire-straightening length reaches the length L-L1-L2. After the clamping force of the two-finger gripper is increased to clamp the wire, the robot arm is controlled to move the flexible wire 2 to the target position 3 and then lay it out. L is the total length of the wire required for the current target position 3.

[0064] The grasping stage, the calibration stage, and the wiring stage are repeated in sequence until all target positions 3 are arranged, thereby completing the wiring of the flexible wire 2.

[0065] The present invention employs an adaptive two-finger gripper with a three-dimensional force tactile sensor array 1 installed on both sides of the gripper as a tactile sensing device. This array can detect the distribution of normal and tangential forces. The robot is not equipped with any additional six-dimensional force sensors or visual sensors for additional force or visual feedback. The object being manipulated, a flexible wire 2, is a slender wire made of a soft material that undergoes significant deformation under external force. For example, the flexible wire 2 is a cable.

[0066] Based on the pressure distribution data fed back by the tactile sensors, the position of the wire within the gripper can be estimated and adjusted to ensure that the wire remains near the center of the gripper. The gripper force is also adjusted to maintain effective contact between the gripper and the wire to prevent it from slipping. The entire operation process is divided into three stages: grasping, calibration, and threading (following the wire's contour and driving its movement). After grasping the wire, the 3D force distribution data fed back by the tactile sensor array 1 is monitored in real time. The tactile servo control framework continuously adjusts the gripper posture and gripper opening and closing force at the end of the robotic arm to follow the wire's contour, improving the trajectory and joint output speed accuracy. After threading the wire for a certain length, the robot moves to the target position, switches to the working mode, and begins laying the wire, completing one stage of the operation. This process is repeated to achieve complete layout of a long wire. When laying wires for different target positions 3, the values ​​of L corresponding to each target position 3 may be the same or different, depending on the actual work scenario. The value of L1 for each target position 3 is the same, and the value of L2 for each target position 3 may be the same or different.

[0067] The tactile servo control method for flexible wire routing described in this embodiment divides the routing task into three stages: grasping, calibration, and threading, ensuring accurate and efficient operation. Furthermore, the entire control method relies entirely on tactile perception and can complete the task without visual feedback.

[0068] The use of a three-dimensional force tactile sensor array can directly obtain effective three-dimensional force information, with fast calculation, low sensor cost and long life. The three-dimensional force tactile sensor array is divided into two areas: the grasping sensing area and the wire dropping sensing area. The utilization of the tangential force and normal force in the three-dimensional force array information is more perfect. The tangential force is used to control the opening and closing of the clamping jaws, that is, the size of the contact force, to ensure that the force is moderate during the process of following the wire contour, and the wire pulling is gentle without damaging the wire. The control of the robot arm and the clamping jaws is more comprehensive and accurate, with both force control and posture control, making the control effect smoother. It does not need to rely on visual sensors and does not need to consider whether the line of sight is blocked. It can sense linear changes and realize line operations, ensuring that the wire will not be damaged while completing the task. The present invention is more suitable for complex industrial scenarios.

[0069] Specifically, the three-dimensional force tactile sensing array is an array composed of a plurality of coarse sensing units. As an example, the area ratio of the overlapping area to the non-overlapping area on each three-dimensional force tactile sensing array 1 is 3:1 or 2:1. Figure 5 Two-thirds of the sensing areas overlap, as shown in red, and one-third of the areas are offset, as shown in green. In specific applications, the three-dimensional force tactile sensing array is implemented using a capacitive three-dimensional force tactile sensing array.

[0070] For further information, see Figure 6 , extracting the normal force distribution data sensed by the grasping sensing area 1-1, controlling the position of the two-finger gripper during the movement along the length direction of the flexible wire 2, and making a section of the flexible wire 2 in the grasping sensing area 1-1 effectively contact the two-finger gripper. The implementation method includes:

[0071] S11. In the direction in which the two-finger gripper is directed toward the flexible wire 2, establish a spatial coordinate system for the robotic arm with the midpoint of the outer wide side of the grasping sensing area 1-1 of each three-dimensional force tactile sensing array 1 as the origin, the direction in the plane of the grasping sensing area 1-1 pointing toward the wire falling sensing area 1-2 as the x-axis direction, the direction pointing forward as the y-axis direction, and the direction perpendicular to the plane of the x-axis and y-axis and pointing downward as the z-axis direction;

[0072] S12, converting the normal force distribution data sensed by the grasping sensing area 1-1 of each three-dimensional force tactile sensing array 1 into a grayscale image, and analyzing the grayscale image using an image moment analysis method to obtain the centroid coordinates and principal component directions;

[0073] According to the coordinates of the center of mass, determine the position deviation Δx of the center of mass relative to the origin in the x-axis direction and the position deviation Δy in the y-axis direction;

[0074] The angle between the principal component direction and the x-axis direction is taken as the principal component offset angle Δα;

[0075] S13, the position deviation Δx in the x-axis direction, the position deviation Δy in the y-axis direction, and the principal component offset angle Δα corresponding to the two three-dimensional force tactile sensor arrays 1 are averaged to obtain the position deviation mean in the x-axis direction. Position deviation in the y-axis direction and principal component offset angle

[0076] S14, during the movement of the two-finger gripper along the length direction of the flexible wire 2, according to the current and The value of adjusts the posture of the two-finger gripper so that and approaches 0 and satisfies When , it is determined that a section of flexible wire 2 in the grasping sensing area 1-1 is in effective contact with the two-finger gripper, wherein δ1 and δ2 are both positive numbers.

[0077] In this preferred embodiment, the implementation process of determining the effective contact between a section of flexible wire 2 and the two-finger gripper in the gripping sensing area 1-1 is given. By making full use of the normal force distribution information of the sensor array, converting it into a tactile image and using image processing methods, the relative posture of the wire and the gripper can be simply and efficiently determined, and the posture deviation can be directly mapped to the robot arm control. The control quantity is accurate, the calculation efficiency is fast, and the real-time performance is good. In specific applications, the corresponding control quantity is generated for the robot arm control, and the corresponding control quantity can be generated by inputting the feedback data into the model predictive control optimization solver in the prior art. The relative posture of the gripper and the wire can be transformed in real time to ensure that the wire always remains near the center of the gripper during the wire contour following process to avoid falling;

[0078] For details, see Figure 6 In step S14, according to the current and The value of is used to adjust the posture of the two-finger gripper as follows:

[0079] When , the two-finger gripper is controlled to move along the positive direction of the x-axis, otherwise, the two-finger gripper is controlled to move along the negative direction of the x-axis;

[0080] When , the two-finger gripper is controlled to move along the positive direction of the y-axis, otherwise, the two-finger gripper is controlled to move along the negative direction of the y-axis;

[0081] When the two-finger gripper is in the state of rotation, the two-finger gripper is controlled to rotate clockwise around the z-axis; otherwise, the two-finger gripper is controlled to rotate counterclockwise around the z-axis.

[0082] Furthermore, the implementation method of sensing the drooping deviation of the flexible wire 2 through the wire drooping sensing area 1-2 is as follows:

[0083] S21, calculate F according to the normal force distribution data sensed by the wire drop sensing area 1-2 of each three-dimensional force tactile sensing array 1 θ1 and F θ2 ; F θ1 and F θ2 is the resultant force in the normal direction of all the contact points of the wire drop sensing area 1-2 of the three-dimensional force tactile sensing array 1 located at the bottom and the top respectively, and F θ1 and F θ2 All are scalar;

[0084] S22, calculate the profile drop deviation ΔF=F θ1 -F θ2 The wire droop sensing areas 1-2 sense different wire droop states, which are reflected by the contour droop deviation.

[0085] In this preferred embodiment, the implementation method of sensing the drooping deviation of the contour of the flexible wire 2 is given with reference to the tactile feedback when a person strokes the wire with eyes closed. The drooping bending state of the wire can be sensed in advance, and the movement along the z-axis and the rotation around the y-axis are reflected by a scalar, which makes the control simple, direct and efficient.

[0086] Furthermore, in the wire drawing stage, the two-finger gripper is controlled to perform a wire drawing operation along the contour drop direction of the flexible wire 2 in three-dimensional space according to the contour drop deviation as follows:

[0087] When ΔF>0, the two-finger gripper is controlled to move along the positive direction of the z-axis of the robot arm's spatial coordinate system and rotate clockwise around the y-axis;

[0088] When ΔF<0, the two-finger gripper is controlled to move along the negative direction of the z-axis of the robot arm's spatial coordinate system and rotate counterclockwise around the y-axis;

[0089] Among them, the spatial coordinate system of the robotic arm is a coordinate system established in the direction of the two-finger gripper toward the flexible wire 2, with the midpoint of the outer wide side of the grasping sensing area 1-1 of each three-dimensional force tactile sensing array 1 as the origin, the direction pointing to the wire falling sensing area 1-2 in the plane where the grasping sensing area 1-1 is located as the x-axis direction, the direction pointing forward as the y-axis direction, and the direction perpendicular to the plane where the x-axis and y-axis are located and pointing downward as the z-axis direction.

[0090] In this preferred embodiment, the three-dimensional force tactile sensing array 1 is divided into a grasping sensing area 1-1 and a wire dropping sensing area 1-2, which fully utilizes the normal force information sensed by the wire dropping sensing area 1-2, and performs coordinated control of the force and posture of the robotic arm and the gripper. The output effect is smoother, and the wiring task can be completed efficiently without visual feedback, while ensuring that the wire will not be damaged.

[0091] Specific embodiment 2: The tactile servo control device for flexible wire wiring operations described in this embodiment includes a storage device, a processor, and a computer program stored in the storage device and runnable on the processor. The processor executes the computer program to implement the tactile servo control method for flexible wire wiring operations as described in specific embodiment 1.

[0092] Specific embodiment 3: This embodiment describes a computer-readable storage device, wherein the storage device stores a computer program. When the computer program is executed, the tactile servo control method for flexible wire wiring operations as described in specific embodiment 1 is implemented.

[0093] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It should be understood that many modifications may be made to the illustrative embodiments, and that other arrangements may be devised, without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in ways other than those described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be employed in conjunction with other described embodiments.

Claims

1. A tactile servo control method for flexible wire routing operations, the method being based on a three-dimensional force tactile sensor array (1) installed in the upper and lower clamping surfaces of a two-finger gripper at the end of a robotic arm, and a flexible wire (2) with one end fixed and the other end in a free state, wherein the two three-dimensional force tactile sensor arrays (1) are arranged relative to each other and partially overlap, wherein: The overlapping area and non-overlapping area of ​​each three-dimensional force tactile sensing array (1) are both rectangular arrays, and the two are respectively defined as a grasping sensing area (1-1) and a wire falling sensing area (1-2); the method is characterized in that it includes the following steps: Grasping stage: gripping the flexible wire (2) with a two-finger gripper, and recording the distance L1 between the current gripping position and the nearest fixed end of the flexible wire (2); Calibration phase: Extracting the tangential force distribution data sensed by the gripping sensing area (1-1) in real time, and controlling the gripping force of the two-finger gripper so that the friction force between the two-finger gripper and the flexible wire (2) is within a preset range; Extract the normal force distribution data sensed by the grasping sensing area (1-1), control the posture of the two-finger gripper during the movement along the length direction of the flexible wire (2), so that a section of the flexible wire (2) in the grasping sensing area (1-1) is effectively in contact with the two-finger gripper. At this time, record the movement distance L2 of the two-finger gripper along the length direction of the flexible wire (2) during the calibration phase, and the contour drooping deviation of the flexible wire (2) sensed by the wire drooping sensing area (1-2); Threading stage: Extracting the tangential force distribution data sensed by the gripping sensing area (1-1) in real time, and controlling the gripping force of the two-finger gripper so that the friction force between the two-finger gripper and the flexible wire (2) is within a preset range; While maintaining effective contact between a section of flexible wire (2) in the grasping sensing area (1-1) and the two-finger gripper, the two-finger gripper is controlled to perform a wire pulling operation along the contour dropping direction of the flexible wire (2) in three-dimensional space according to the contour dropping deviation, and the wire pulling operation is stopped after the wire pulling length reaches the length L-L1-L2; after increasing the clamping force of the two-finger gripper to clamp the wire, the robot arm is controlled to clamp the flexible wire (2) and move it to the target position (3) for layout; L is the total length of the wire required for the current target position (3); The grasping stage, the calibration stage and the wiring stage are repeated in sequence until all target positions (3) are arranged, thereby completing the wiring of the flexible wire (2).

2. The tactile servo control method for flexible wire routing according to claim 1, characterized in that: Extracting the normal force distribution data sensed by the grasping sensing area (1-1), controlling the posture of the two-finger gripper during the movement along the length direction of the flexible wire (2), and making a section of the flexible wire (2) in the grasping sensing area (1-1) effectively contact the two-finger gripper is achieved by: S11. In the direction of the two-finger gripper toward the flexible wire (2), the midpoint of the outer wide side of the grasping sensing area (1-1) of each three-dimensional force tactile sensing array (1) is used as the origin, the direction of the grasping sensing area (1-1) pointing to the wire falling sensing area (1-2) in the plane where the grasping sensing area (1-1) is located is used as the x-axis direction, the direction pointing forward is used as the y-axis direction, and the direction perpendicular to the plane where the x-axis and y-axis are located and pointing downward is used as the z-axis direction, and a spatial coordinate system of the robotic arm is established; S12, converting the normal force distribution data sensed by the grasping sensing area (1-1) of each three-dimensional force tactile sensing array (1) into a grayscale image, analyzing the grayscale image using an image moment analysis method to obtain the centroid coordinates and principal component directions; According to the coordinates of the center of mass, determine the position deviation of the center of mass relative to the origin in the x-axis direction , Position deviation in the y-axis direction ; The angle between the principal component direction and the x-axis direction is used as the principal component offset angle ; S13, the position deviation in the x-axis direction corresponding to the two three-dimensional force tactile sensor arrays (1) , position deviation in the y-axis direction and principal component offset angle Take the average respectively to get the mean value of the position deviation in the x-axis direction , the mean position deviation in the y-axis direction and the mean of the principal component deviation angles ; S14, during the movement of the two-finger gripper along the length direction of the flexible wire (2), according to the current 、 and The value of adjusts the posture of the two-finger gripper so that 、 and approaches 0, and at the same time satisfies | |<δ1,| When |<δ2, it is determined that a section of flexible wire (2) in the grasping sensing area (1-1) is in effective contact with the two-finger gripper, wherein δ1 and δ2 are both positive numbers.

3. The tactile servo control method for flexible wire routing according to claim 2, characterized in that: In step S14, according to the current 、 and The value of is used to adjust the posture of the two-finger gripper as follows: When >0, the two-finger gripper is controlled to move along the positive direction of the x-axis; otherwise, the two-finger gripper is controlled to move along the negative direction of the x-axis; When >0, the two-finger gripper is controlled to move along the positive direction of the y-axis; otherwise, the two-finger gripper is controlled to move along the negative direction of the y-axis; When >0, the two-finger gripper is controlled to rotate clockwise around the z-axis; otherwise, the two-finger gripper is controlled to rotate counterclockwise around the z-axis.

4. The tactile servo control method for flexible wire routing according to claim 1, characterized in that: The method for sensing the profile droop deviation of the flexible wire (2) through the wire droop sensing area (1-2) is as follows: S21, calculate the normal force distribution data sensed by the wire drop sensing area (1-2) of each three-dimensional force tactile sensing array (1), and ; and are the resultant forces in the normal direction of all the contact points in the wire drop sensing area (1-2) of the three-dimensional force tactile sensing array (1) located below and above, respectively, and and All are scalar; S22. Calculate the contour drop deviation .

5. The tactile servo control method for flexible wire routing according to claim 4, characterized in that: The method for controlling the two-finger gripper to perform the wire-straightening operation along the direction of the flexible wire (2) in the three-dimensional space according to the deviation of the contour drooping is as follows: When >0, the two-finger gripper is controlled to move along the positive direction of the z-axis of the robot arm's spatial coordinate system and rotate clockwise around the y-axis; When <0, the two-finger gripper is controlled to move along the negative direction of the z-axis of the robot arm's spatial coordinate system and rotate counterclockwise around the y-axis; The robot arm spatial coordinate system is a coordinate system established in the direction of the two-finger gripper toward the flexible wire (2), with the midpoint of the outer wide side of the grasping sensing area (1-1) of each three-dimensional force tactile sensing array (1) as the origin, the direction of the grasping sensing area (1-1) pointing to the wire falling sensing area (1-2) in the plane where the grasping sensing area (1-1) is located as the x-axis direction, the direction pointing forward as the y-axis direction, and the direction perpendicular to the plane where the x-axis and y-axis are located and pointing downward as the z-axis direction.

6. The tactile servo control method for flexible wire routing according to claim 1, characterized in that: When wiring for different target positions (3), the values ​​of L corresponding to each target position (3) are the same or different, and the values ​​of L1 corresponding to each target position (3) are the same, and the values ​​of L2 corresponding to each target position (3) are the same or different.

7. The tactile servo control method for flexible wire routing according to claim 1, characterized in that: The area ratio of the overlapping area to the non-overlapping area on each three-dimensional force tactile sensing array (1) is 3:1 or 2:

1.

8. The tactile servo control method for flexible wire routing according to claim 1, characterized in that: The three-dimensional force tactile sensing array (1) is implemented using a capacitive three-dimensional force tactile sensing array.

9. A tactile servo control device for flexible wire routing operations, comprising a storage device, a processor, and a computer program stored in the storage device and executable on the processor, characterized in that: The processor executes the computer program to implement the tactile servo control method for flexible wire wiring operations as described in any one of claims 1 to 7.

10. A computer-readable storage device, characterized in that: The storage device stores a computer program, wherein when the computer program is executed, the tactile servo control method for flexible wire wiring operations according to any one of claims 1 to 7 is implemented.

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