Control method, system and apparatus for cable-driven parallel robot, and medium

Abstract

A control method, system and apparatus for a cable-driven parallel robot, and a storage medium, which are used for controlling eight electric motors of a cable-driven parallel robot. For any target electric motor, the control method comprises: acquiring the current position of a target electric motor in motion, wherein the target electric motor is the first electric motor to move; and controlling the target electric motor to move at a first speed, and when the distance difference between the current position and a preset target position is less than or equal to a first preset threshold value, adjusting the first speed to a second speed, wherein the second speed is less than the first speed.

Description

A rope-pulled parallel robot control method, system, device and medium Technical Field

[0001] The present application relates to the technical field of rope-pulled parallel robots, and in particular to a rope-pulled parallel robot control method, system, device and storage medium. Background Art

[0002] Cable-driven parallel robots are used in large workspaces and at high working speeds, and the quality and elasticity of the cables need to be considered in order to accurately analyze the kinematics, dynamics, workspace, trajectory planning, and control. The motor is connected to multiple elastic ropes and its operation is controlled by the motor that controls the ropes. Trajectory planning refers to planning the running path, running speed, and tension of the motor and the pulling ropes. The motor is pulled by multiple ropes, which jointly control its operation. Each rope is controlled by its own motor. Although each motor has encoder feedback, there may be certain differences and uncertainties in the driver components, and there may be differences in the command execution time and motor response time. Therefore, during the control process, it may be possible that multiple motors cannot reach the target position point accurately at the same time, and there may be situations such as jamming and poor movement before and after reaching any target point. Therefore, there are still technical problems that need to be solved in the relevant technology.

[0003] Summary of the Invention

[0004] The purpose of this application is to solve one of the technical problems existing in the prior art to at least a certain extent.

[0005] To this end, one purpose of the embodiments of the present application is to provide a rope-pulled parallel robot control method, system, device and storage medium, which can reduce the phenomenon of motion jamming and unsmoothness in the rope-pulled parallel robot.

[0006] To achieve the above technical objectives, the technical solution adopted in the embodiments of the present application includes: a rope-pulled parallel robot control method for controlling eight motors of the rope-pulled parallel robot. For any target motor, the control method includes:

[0007] Obtaining the current position of the target motor; the target motor is the motor that moves first;

[0008] The target motor is controlled to move at a first speed, and when the distance difference between the current position and the preset target position is less than or equal to a first preset threshold, the first speed is adjusted to a second speed; wherein the second speed is less than the first speed.

[0009] In addition, the method for controlling a rope-pulled parallel robot according to the above embodiment of the present invention may also have the following additional technical features:

[0010] Furthermore, in an embodiment of the present application, the control method further includes: when the distance difference between the current position of the target motor and the target position is greater than a first preset threshold, controlling the motor to move at the first speed.

[0011] Furthermore, in the embodiment of the present application, the first speed and the second speed satisfy the following relationship: V1=V0 / N;

[0012] Wherein V1 is the second speed, V0 is the first speed, and N is 2≤N≤10, where N is an integer.

[0013] Furthermore, in an embodiment of the present application, the step of adjusting the first speed to the second speed when the distance difference between the current position and the preset target position is less than or equal to a first preset threshold value specifically includes: for any one of the target motors, when the distance difference between the current position of the motor movement and the preset target position is less than or equal to the first preset threshold value, adjusting the speed of the target motor from the first speed to the second speed, and controlling the motor at the second speed until the positions of the remaining seven motors reach the first preset position.

[0014] Furthermore, in an embodiment of the present application, the control method also includes: when the distance difference between the position of any one of the target motors and the target position is less than or equal to a first preset threshold, and the distance difference between the positions of the remaining seven motors and the second preset position is less than or equal to a second preset threshold, controlling the eight motors to move at a third speed.

[0015] Furthermore, in an embodiment of the present application, the third speed is greater than the second speed.

[0016] On the other hand, an embodiment of the present application also provides a rope-traction parallel robot control system for controlling the eight motors of the rope-traction parallel robot. The system includes: an acquisition unit for acquiring the current position of the target motor movement; a first control unit for controlling the target motor movement at a first speed, and when the distance difference between the current position and the preset target position is less than or equal to a first preset threshold, adjusting the first speed to a second speed; wherein the second speed is less than the first speed.

[0017] Furthermore, in an embodiment of the present application, the system further includes a second control unit configured to control the motor to move at the first speed when the distance difference between the current position and the preset target position is greater than a first preset threshold.

[0018] On the other hand, the present application also provides a rope-pulled parallel robot control device, comprising:

[0019] at least one processor;

[0020] at least one memory for storing at least one program;

[0021] When the at least one program is executed by the at least one processor, the at least one processor implements a rope-traction parallel robot control method as described in any one of the invention contents.

[0022] In addition, the present application also provides a storage medium storing processor-executable instructions, which, when executed by the processor, are used to execute a rope-traction parallel robot control method as described in any one of the above items.

[0023] The advantages and benefits of this application will be partially given in the following description, and partially become apparent from the following description, or learned through practice of this application:

[0024] The present application can obtain the current position of the target motor that moves first among any of the eight motors; and control the movement of the target motor at a first speed. When the distance difference between the current position of the target motor and the target position is less than or equal to a first preset threshold, the present application can adjust the first speed to a second speed that is less than the first speed, so that before reaching the target position, the position between the target motor and the remaining seven motors can be continuously reduced, thereby improving the phenomenon of motion jamming and unsmoothness among the eight motors. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a schematic structural diagram of a rope-pulled parallel robot in the prior art;

[0026] FIG2 is a schematic structural diagram of trajectory generation of a rope-pulled parallel robot in the prior art;

[0027] FIG3 is a schematic diagram of the steps of a rope-pulling parallel robot control method in a specific embodiment of the present invention;

[0028] FIG4 is a schematic diagram of the steps of a control method for a rope-pulled parallel robot in another specific embodiment of the present invention;

[0029] FIG5 is a schematic structural diagram of a rope-pulling parallel robot control system in a specific embodiment of the present invention;

[0030] FIG6 is a schematic structural diagram of a rope-pulled parallel robot control device in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0031] The following describes the embodiments of the present invention in detail with reference to the accompanying drawings to illustrate the principles and processes of the rope-pulled parallel robot control method, system, device and storage medium in the embodiments of the present invention.

[0032] A cable-driven parallel robot, with cables as transmission elements, is a relatively flexible parallel robot. It primarily consists of a frame, pulleys, drive motors, cables, and an end effector, as shown in Figure 1. The end effector is located in the center of the frame. The end effector is directly controlled by eight cables, which are directly driven and controlled by eight motors. An algorithm plans the movement or rotation path of the end effector, as well as the corresponding position and speed of the eight cables. The controller then issues commands to the various motor drivers for execution.

[0033] The trajectory generation method is introduced in conjunction with Figure 2. The end effector is a cuboid with the coordinates of the geometric center point (x, y, z) and the length, width and height of a, b, and c respectively. The length of the rope from the 8 fixed points of the end effector to the 8 pulleys of the machine is l i , the length is fixed, i is 1, 2, ..., 8. a i are the coordinates of the 8 pulleys, b i is the coordinate of the 8 fixed points of the end effector, and R is the rotation matrix of the actuator. The fixed length expression of the rope is obtained: i =a i -r-Rb i , i=1,2,...,8。

[0034] Taking the straight line running upward on the most track as an example, the rotation matrix is ​​the unit matrix E, that is, l i =a i -rb i By taking the derivative of each rope segment, we can get the running speed of each rope:

[0035] in

[0036] During the operation of the end effector, each rope is controlled individually by its own driver. Although each motor has encoder feedback, there may be certain differences and uncertainties in the driver components. The command execution time and motor response time may also vary. It is possible that multiple motors cannot reach the target position accurately at the same time.

[0037] In response to the shortcomings of the prior art described above, the present application provides a control method for a rope-pulled parallel robot. This method can be used to control the eight motors of a rope-pulled parallel robot. For any target motor, the specific steps of the control method can be referred to FIG1 , which is a schematic diagram of the steps of the control method for a rope-pulled parallel robot. In FIG1 , the control method may include, but is not limited to, steps S101 to S102:

[0038] S101, obtaining the current position of the target motor; the target motor is the motor that moves first;

[0039] It's understandable that as the motor rotates, the tightening of the rope causes the motor to move along a specific trajectory, and the motor's current position can be any point along the trajectory. However, due to factors such as different response times and subtle differences in the internal magnetic field of each motor, the time at which each motor starts moving varies. Therefore, the target motor can be the first to move, or the motor that moves the earliest.

[0040] In some feasible embodiments of the present application, the acquisition module can obtain the current position of the target motor movement, and then establish a wired or wireless connection with the processor to send the obtained current position of the target motor movement to the processor for further processing.

[0041] It should be noted that the aforementioned wired connection methods may include connections between mobile devices and a host computer, connections between host computers, and other wired connections between devices currently known or developed in the future. The aforementioned wireless connection methods may include, but are not limited to, 3G / 4G / 5G connections, WiFi connections, Bluetooth connections, WiMAX connections, Zigbee connections, UWB (Ultra Wide Band) connections, and other wireless connection methods currently known or developed in the future. The acquisition module may be a separate device, such as a processor that converts motor codes into corresponding positions, or the acquisition module may be integrated with the processor into a single module.

[0042] S102 , controlling the target motor to move at a first speed, and when the distance difference between the current position and the preset target position is less than or equal to a first preset threshold, adjusting the first speed to a second speed; wherein the second speed is less than the first speed.

[0043] It is understood that the first speed can be a pre-set speed. After the motor is turned on, the motor can slowly accelerate to the pre-set speed over a short period of time. The first speed can be any value, and the specific value can be determined based on specific needs. The second speed is the speed adjusted after the motor reaches the specified position. The second speed can be any value less than the first speed, and the specific value can be determined based on specific needs.

[0044] In some feasible embodiments of the present application, the controller may first control the target motor to move at a first speed. When the target motor moves to a position where the distance difference between the current position and the preset target position is less than or equal to a first preset threshold, the controller may control the motor to move at a second speed, where the second speed may be less than the first speed.

[0045] Furthermore, in some feasible embodiments of the present application, the rope-pulled parallel robot control method may further include: S103: when the distance difference between the current position of the target motor and the target position is greater than a first preset threshold, controlling the motor to move at a first speed. Specifically, if the motor has not reached the preset area, the controller may control the motor to continue moving at the first speed.

[0046] Furthermore, in some feasible embodiments of the present application, the first speed and the second speed satisfy the following relationship: V1=V0 / N;

[0047] Wherein V1 is the second speed, V0 is the first speed, and N is 2≤N≤10, where N is an integer.

[0048] Furthermore, in some feasible embodiments of the present application, when the distance difference between the current position and the preset target position is less than or equal to a first preset threshold, the step of adjusting the first speed to the second speed may specifically include: for any target motor, when the distance difference between the current position of the motor movement and the preset target position is less than or equal to the first preset threshold, adjusting the speed of the target motor from the first speed to the second speed, and controlling the motor at the second speed until the positions of the remaining seven motors reach the first preset position. Specifically, the first preset position may be any position point in the trajectories of the other seven motors where the distance difference between the target position and the target position is less than or equal to the first preset threshold.

[0049] Furthermore, in some feasible embodiments of the present application, the rope-traction parallel robot control method may further include: when the distance difference between the position of any target motor and the target position is less than or equal to a first preset threshold, and the distance difference between the positions of the remaining seven motors and the second preset position is less than or equal to a second preset threshold, controlling the eight motors to move at a third speed. Specifically, when the motor that was started first approaches the target position and the other seven motors also reach the target points of the trajectories corresponding to the seven motors, the control module may control the eight motors to move at a third speed. It is understandable that the third speed may be the same as the first speed, may be greater than the first speed, or may be less than the first speed, and the specific speed value may be determined according to actual conditions.

[0050] Furthermore, in some feasible embodiments of the present application, the third speed is greater than the second speed. Specifically, the second speed is a speed that is adjusted to be smaller than the first speed. After all seven motors reach the target position, the present application adjusts the speed of the motors to the third speed that is greater than the speed after deceleration.

[0051] The specific calculation principle of this application is explained below with reference to the accompanying drawings:

[0052] Referring to Figure 4 , in this embodiment, the motors can be set to have a first speed of vn, where n is 1-8, a second speed of vn / N, and a third speed of vdn, where n is 1-8. The first preset threshold value is value. This threshold value is located in a small area near the target point. When the motors' preset first speed vn falls within this threshold range, they are considered to have reached the target point. A check is performed to see if all motors have reached the threshold range. Once all motors have reached the threshold, the trajectory is switched to the speed vdn corresponding to the next target point. If any motors have not reached the threshold, they continue to run. Motors that have reached the threshold run at a speed of vn / N, where vn / N is less than vn.

[0053] For example, if the current position of motor 1 is s1, the current running speed is v1, the target point position is sd1, and the target point speed is vd1, when sd1-s1<=value, the threshold is marked. At this time, the current value speed is set to v1 / N.

[0054] Motor 2 current position s2, current running speed v2, target point position sd2, target point speed vd2, when sd2-s2<=value, the threshold mark, at this time, the current value speed is set to v2 / N.

[0055] Motor 3 current position s3, current running speed v3, target point position sd3, target point speed vd3, when sd3-s3<=value, the threshold mark, at this time, the current value speed is set to v3 / N.

[0056] Motor 4 current position s4, current running speed v4, target point position sd4, target point speed vd4, when sd4-s4<=value, the threshold mark, at this time, the current value speed is set to v4 / N.

[0057] Motor 5 current position s5, current running speed v5, target point position sd5, target point speed vd5, when sd5-s5<=value, threshold mark, at this time, the current value speed is set to v5 / N.

[0058] Motor 6 current position s6, current running speed v6, target point position sd6, target point speed vd6, when sd6-s6<=value, the threshold mark, at this time, the current value speed is set to v6 / N.

[0059] Motor 7 current position s7, current running speed v7, target point position sd7, target point speed vd7, when sd7-s7<=value, threshold mark, at this time, the current value speed is set to v7 / N.

[0060] The current position of motor 8 is s8, the current running speed is v8, the target point position is sd8, and the target point speed is vd8. When sd8-s8<=value, the threshold is marked. At this time, the current value speed is set to v8 / N.

[0061] Here, N is an integer ranging from 1 to 10. When N=1, the motor continues to run at the current speed after entering the threshold, and the speed remains unchanged.

[0062] When N is an integer greater than 1, the motor decelerates after entering the threshold. When N=2, the speed of the motor in the threshold is v1 / 2, that is, the motor speed is reduced by half.

[0063] When all eight motors enter the threshold range, the current motion state switches to the state of the next trajectory planning target point, and moves to the position of the next point at the speed vdn of the next point.

[0064] In addition, referring to FIG5 , corresponding to the method of FIG1 , an embodiment of the present application further provides a rope-pulled parallel robot control system. The system can be used to control the eight motors of the rope-pulled parallel robot. The system can include an acquisition unit 1001 and a first control unit 1002. The acquisition unit 1001 can be connected to the first control unit 1002 by signal. The acquisition unit 1001 can be used to determine the current position of the target motor; the target motor is the first motor to move; the first control module 1002 can control the motor to move at a first speed, and when the distance difference between the current position and the preset target position is less than or equal to a first preset threshold, the first speed is adjusted to a second speed; wherein the second speed is less than the first speed.

[0065] It is understandable that the acquisition unit may be integrated with the first control unit in a processing module, or may perform data transmission with the first control unit via a communication protocol.

[0066] Furthermore, in some feasible embodiments of the present application, the rope-pulled parallel robot control system may further include a second control unit 1003. The second control unit 1003 may be configured to control the motor to move at a first speed when the distance difference between the current position and the preset target position is greater than a first preset threshold.

[0067] It is understandable that the second control unit and the first control unit may belong to different parts of the same processor or processing chip, or may be different control units of the same processor executing different control algorithms.

[0068] It should be noted that the contents of the above-mentioned rope-traction parallel robot control method embodiment are all applicable to the present rope-traction parallel robot control system embodiment. The functions specifically implemented by the present rope-traction parallel robot control system embodiment are the same as those of the above-mentioned rope-traction parallel robot control method embodiment, and the beneficial effects achieved are also the same as those achieved by the above-mentioned rope-traction parallel robot control method embodiment.

[0069] Corresponding to the method of FIG1 , the embodiment of the present application further provides a rope-pulled parallel robot control device, the specific structure of which can be referred to FIG6 , including:

[0070] at least one processor 1011;

[0071] at least one memory 1012, configured to store at least one program;

[0072] When the at least one program is executed by the at least one processor, the at least one processor implements the rope-traction parallel robot control method.

[0073] It should be noted that the contents of the above method embodiments are all applicable to the present device embodiments. The functions specifically implemented by the present device embodiments are the same as those of the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

[0074] Corresponding to the method of FIG1 , an embodiment of the present application further provides a storage medium storing processor-executable instructions, which are used to execute the rope-traction parallel robot control method when executed by the processor.

[0075] It should be noted that the contents of the above-mentioned rope-traction parallel robot control method embodiment are all applicable to the present storage medium embodiment. The functions specifically implemented by the present storage medium embodiment are the same as those of the above-mentioned rope-traction parallel robot control method embodiment, and the beneficial effects achieved are also the same as those achieved by the above-mentioned rope-traction parallel robot control method embodiment.

[0076] In some optional embodiments, the function / operation mentioned in the block diagram may not occur in the order mentioned in the operation diagram. For example, depending on the function / operation involved, the two boxes shown in succession can actually be executed substantially simultaneously or the boxes can sometimes be executed in reverse order. In addition, the embodiments presented and described in the flow chart of the present application are provided in an exemplary manner for the purpose of providing a more comprehensive understanding of the technology. The disclosed method is not limited to the operations and logical flows presented herein. Optional embodiments are contemplated in which the order of the various operations is changed and the sub-operations described as a part of a larger operation are performed independently.

[0077] In addition, although the present application is described in the context of functional modules, it should be understood that, unless otherwise stated, one or more of the functions and / or features may be integrated into a single physical device and / or software module, or one or more functions and / or features may be implemented in separate physical devices or software modules. It is also understood that a detailed discussion of the actual implementation of each module is not necessary for understanding the present application. More specifically, given the properties, functions, and internal relationships of the various functional modules in the devices disclosed herein, the actual implementation of the module will be understood within the routine skills of an engineer. Therefore, a person skilled in the art can implement the present application as set forth in the claims using ordinary techniques without undue experimentation. It is also understood that the specific concepts disclosed are merely illustrative and are not intended to limit the scope of the present application, which is determined by the full scope of the appended claims and their equivalents.

[0078] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several programs for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0079] The logic and / or steps represented in a flowchart or otherwise described herein, for example, may be considered as an ordered list of executable programs for implementing the logical functions, and may be embodied in any computer-readable medium for use by, or in conjunction with, a program execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can retrieve and execute a program from a program execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" may be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, a program execution system, apparatus, or device.

[0080] More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0081] It should be understood that various parts of the present application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable program execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0082] In the above description of this specification, reference to the terms "one embodiment / example," "another embodiment / example," or "certain embodiments / examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples.

[0083] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

[0084] The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present application. These equivalent modifications or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. A control method for a rope-driven parallel robot, characterized in that: For controlling eight motors of a rope-pulled parallel robot, for any target motor, the control method includes: Acquire the current position of the target motor; the target motor is the motor that moves first; The target motor is controlled to move at a first speed, and when the distance difference between the current position and the preset target position is less than or equal to a first preset threshold, the first speed is adjusted to a second speed; wherein the second speed is less than the first speed.

2. A control method for a rope-driven parallel robot according to claim 1, characterized in that: The control method further includes: when a distance difference between the current position of the target motor and the target position is greater than a first preset threshold, controlling the motor to move at the first speed.

3. The control method of a rope-pulled parallel robot according to claim 1, characterized in that: The first speed and the second speed satisfy the following relationship: V1 = V0 / N; Wherein V1 is the second speed, V0 is the first speed, N is 2≤N≤10, and N is an integer.

4. The control method of a rope-pulled parallel robot according to claim 1, characterized in that: The step of adjusting the first speed to the second speed when the distance difference between the current position and the preset target position is less than or equal to a first preset threshold value specifically includes: For any one of the target motors, when the distance difference between the current position of the motor movement and the preset target position is less than or equal to a first preset threshold, the speed of the target motor is adjusted from the first speed to the second speed, and the motor is controlled at the second speed until the positions of the remaining seven motors reach the first preset position.

5. A rope-pulled parallel robot control method according to claim 4, characterized in that: The control method further comprises: When the distance difference between the position of any one of the target motors and the target position is less than or equal to the first preset threshold, and the distance difference between the positions of the remaining seven motors and the second preset position is less than or equal to the second preset threshold, the eight motors are controlled to move at a third speed.

6. A rope-pulled parallel robot control method according to claim 5, characterized in that: The third speed is greater than the second speed.

7. A rope-pulled parallel robot control system, characterized in that: Used to control eight motors of the rope-pulled parallel robot, the system includes: An acquisition unit, used for acquiring the current position of the target motor movement; A first control unit is used to control the movement of the target motor at a first speed, and when the distance difference between the current position and the preset target position is less than or equal to a first preset threshold, the first speed is adjusted to a second speed; wherein the second speed is less than the first speed.

8. A rope-pulled parallel robot control system according to claim 7, characterized in that: The system further includes: a second control unit, configured to control the motor to move at the first speed when the distance difference between the current position and the preset target position is greater than a first preset threshold.

9. A rope-pulled parallel robot control device, characterized in that include: at least one processor; at least one memory for storing at least one program; When the at least one program is executed by the at least one processor, the at least one processor implements the rope-traction parallel robot control method as described in any one of claims 1-6.

10. A storage medium storing instructions executable by a processor, characterized in that: The processor-executable instructions are used to execute a rope-traction parallel robot control method as described in any one of claims 1-6 when executed by the processor.

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