A path planning method for a six-degree-of-freedom collaborative robot end effector

Abstract

The application relates to the field of industrial robot control, in particular to a path planning method for a six-degree-of-freedom collaborative robot end effector, which obtains the length and position of a preset peripheral wiring, calculates a torsion range, plans the path of the end effector based on a first six-dimensional coordinate and a second six-dimensional coordinate by using an inverse kinematics algorithm, obtains the rotation angle and rotation direction of a wrist joint, and calculates a final execution path in combination with the torsion range, thereby avoiding the peripheral wiring winding problem of the end effector under the condition that the flange plate of the robot is parallel to the ground and the end effector is axisymmetric, reducing the labor cost and improving the work efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of industrial robot control, in particular to a path planning method for a six-degree-of-freedom collaborative robot end effector. BACKGROUND

[0002] A six-degree-of-freedom robot, also known as a six-axis robot, is a highly flexible industrial robot with six independent rotary joints, capable of adjusting the position and attitude at any position in three-dimensional space. This robot is widely used in welding, assembly, spraying, handling and other industrial automation fields, and is favored for its high precision, high efficiency and flexibility. Whether in the traditional picking and stacking work or in the work process of other conventional six-degree-of-freedom robots controlled by the host computer, the end effector (mechanical hand, clamp or suction cup, etc.) of the collaborative robot will encounter the contradiction between the shaft angle and the yaw angle. Specifically, after the desired end pose of the end effector of the robot is given, the path of the robot end is planned by inverse algorithm, because the yaw angle of the robot has periodicity, resulting in physical over-limit of shaft angle, winding of end effector peripherals, etc. The periodicity is due to the definition domain of the yaw angle being ±180°, so when the yaw angle changes from +180° to -180°, or from -180° to +180°, the direction of the robot end effector is the same from the mathematical and physical point of view.

[0003] The current method to solve the physical over-limit of shaft angle and the winding of end effector peripherals is to artificially add restrictions at the input and output ends of the control program to ensure that the yaw angle does not change too much during the robot operation. However, this method has the following defects: it relies too much on manpower, resulting in low operating efficiency; the limitation parameters are set based on pre-set rules or simple pattern recognition, lacking in-depth analysis of the current situation of the robot operation, thus lacking flexibility and adaptability, i.e. not intelligent enough.

[0004] Therefore, when controlling the operation of a six-degree-of-freedom collaborative robot, how to more efficiently and intelligently avoid the winding or shaft group over-limit of the end effector of the robot is a problem that needs to be solved. SUMMARY

[0005] The present application provides a path planning method for a six-degree-of-freedom collaborative robot end effector, which calculates the twist range of the end effector by obtaining the peripheral wiring length and position of the end effector, and intelligently calculates the operating path of the robot in combination with the axial symmetry of the end effector, thereby avoiding the problems of physical over-limit of the shaft group and winding of peripherals of the end effector when the flange plate of the robot is parallel to the ground and the end effector is axially symmetric.

[0006] To achieve the above purpose, the present application adopts the following technical solutions:

[0007] In a first aspect, the present application provides a path planning method for a six-degree-of-freedom collaborative robot end effector, the method comprising:

[0008] acquiring a first six-dimensional coordinate and a second six-dimensional coordinate of the material;

[0009] constructing a flange coordinate system, the flange coordinate system being based on a flange parallel to the ground;

[0010] obtaining a preset length and position of the peripheral wiring, and calculating a twist range based on the length and position of the peripheral wiring, the length being the length of the peripheral wiring, and the position being the position of the line connecting the two end interfaces of the peripheral wiring in the flange coordinate system;

[0011] planning a path of the end effector based on the first six-dimensional coordinate and the second six-dimensional coordinate using an inverse kinematics algorithm to obtain a rotation angle and a rotation direction of the wrist joint, the rotation direction being a clockwise direction or a counterclockwise direction;

[0012] when the rotation angle is within the twist range, taking the rotation angle and the rotation direction as the final execution path, and when the rotation angle is not within the twist range, taking the supplementary angle of the rotation angle and the opposite direction of the rotation direction as the final execution path.

[0013] In a preferred example of the present application, it can be further provided to further comprise:

[0014] obtaining a preset physical limit value, and calculating the twist range in combination with the physical limit value and the length and position of the peripheral wiring.

[0015] In a preferred example of the present application, the twist range can be equal to 0° to 180°.

[0016] In a preferred example of the present application, the twist range can be equal to 0° to 360°.

[0017] In a preferred example of the present application, the acquisition of the first six-dimensional coordinate and the second six-dimensional coordinate of the material can comprise:

[0018] acquiring the first six-dimensional coordinate and the second six-dimensional coordinate of the material from a host computer of the six-degree-of-freedom collaborative robot.

[0019] In a preferred example of the present application, the acquisition of the preset physical limit value can comprise:

[0020] acquiring the physical limit value from a sensor of the wrist joint shaft group of the robot.

[0021] Secondly, this application provides a path planning device for a six-degree-of-freedom collaborative robot end effector, the device comprising:

[0022] The data acquisition module is used to collect the first and second six-dimensional coordinates of the material.

[0023] A coordinate system construction module is used to construct a flange coordinate system, which is based on a flange parallel to the ground.

[0024] The peripheral module is used to obtain the preset length and position of the peripheral wiring, and calculate the torsion range based on the length and position of the peripheral wiring. The length of the peripheral wiring is the length of the peripheral wiring, and the position is the position of the connection between the two ends of the peripheral wiring in the flange coordinate system.

[0025] The path planning module is used to plan the path of the end effector based on the first six-dimensional coordinates and the second six-dimensional coordinates using an inverse kinematics algorithm, so as to obtain the rotation angle and rotation direction of the wrist joint, wherein the rotation direction is either clockwise or counterclockwise.

[0026] The selection module is used to select the rotation angle and rotation direction as the final execution path when the rotation angle is within the torsion range, and to select the supplementary angle of the rotation angle and the opposite direction of the rotation direction as the final execution path when the rotation angle is not within the torsion range.

[0027] Thirdly, this application provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the path planning method for a six-degree-of-freedom collaborative robot end effector as described in any of the preceding claims.

[0028] Fourthly, this application provides a computer-readable storage medium storing a program, wherein when the program is executed by a processor, it implements the path planning method for a six-degree-of-freedom collaborative robot end effector as described in any of the preceding claims.

[0029] Fifthly, this application provides a computer program product including computer instructions that, when executed by a processor, implement the steps of the path planning method for a six-degree-of-freedom collaborative robot end effector as described in any of the preceding claims.

[0030] In summary, compared with the prior art, the beneficial effects of the technical solution provided in this application include at least the following:

[0031] This application provides a path planning method for a six-degree-of-freedom collaborative robot end effector. By obtaining the preset length and position of the peripheral wiring of the end effector, its torsional range is calculated. Based on the first and second six-dimensional coordinates, an inverse kinematics algorithm is used to plan the path of the end effector, obtaining the rotation angle and direction of the wrist joint. Combined with the value of the peripheral wiring, the final execution path is calculated. This method avoids the problem of peripheral wiring detour of the end effector when the robot's flange is parallel to the ground and the end effector is axisymmetric, reducing labor costs and improving work efficiency. Attached Figure Description

[0032] Figure 1 A flowchart illustrating a path planning method for a six-degree-of-freedom collaborative robot end effector, as provided in one embodiment of this application.

[0033] Figure 2 A comparison diagram of the final execution paths of a path planning method for a six-degree-of-freedom collaborative robot end effector provided in one embodiment of this application.

[0034] Figure 3 This is a structural diagram of a path planning device for a six-degree-of-freedom collaborative robot end effector, provided in one embodiment of this application. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] In one embodiment of this application, a path planning method for a six-degree-of-freedom collaborative robot end effector is provided. Please refer to [link to relevant documentation]. Figure 1 As shown, the method includes:

[0037] S100: The first and second six-dimensional coordinates of the collected material;

[0038] Specifically, the first six-dimensional coordinate is the original coordinate of the material to be moved, and the second six-dimensional coordinate is the expected coordinate of the material to be moved; both are six-dimensional coordinates.

[0039] S200: Construct a flange coordinate system, which is based on a flange parallel to the ground;

[0040] Specifically, the flange is a crucial component connecting the end effector of the six-degree-of-freedom collaborative robot to the robot body. In this embodiment, the plane of the flange is set parallel to the ground. Then, a spatial coordinate system is established based on the plane of the flange, with the origin being the center of the flange.

[0041] S300: Obtain the preset length and position of the peripheral wiring, and calculate the torsion range based on the length and position of the peripheral wiring. The length of the peripheral wiring is the length of the peripheral wiring, and the position is the position of the connection between the two ends of the peripheral wiring in the flange coordinate system.

[0042] Specifically, the user first observes the peripheral wiring, then sets the length and position of the peripheral wiring, which can be represented as a vector. The method obtains this vector to get the preset length and position of the peripheral wiring. The direction of the peripheral wiring is the position of the line connecting the two ends of the peripheral wiring interface in the flange coordinate system, which can be represented by spatial coordinates, and the length is the length of the peripheral wiring. The torsion range is the range of angles that the end effector can rotate to in the flange coordinate system, which can be calculated based on the diameter, height, length, and other data of the end effector, combined with the length and position of the peripheral wiring.

[0043] S400: Based on the first six-dimensional coordinates and the second six-dimensional coordinates, the inverse kinematics algorithm is used to plan the path of the end effector to obtain the rotation angle and rotation direction of the wrist joint, wherein the rotation direction is either clockwise or counterclockwise.

[0044] Specifically, the wrist joint is the connection between the end effector and the six-degree-of-freedom robot body. The wrist joint has the flange. Since the flange is parallel to the ground in this embodiment, the rotation direction is either clockwise or counterclockwise with the flange as the plane.

[0045] S500: When the rotation angle is within the torsion range, the rotation angle and rotation direction are used as the final execution path; when the rotation angle is not within the torsion range, the supplementary angle of the rotation angle and the opposite direction of the rotation direction are used as the final execution path.

[0046] Specifically, please refer to Figure 2 As shown, because the rotation angle planned by the inverse kinematics algorithm is always the shortest path, such as Figure 2 The path shown by F1, assuming the rotation range is in the first and second quadrants (0° to 180°), after rotating in the direction of F1, the end effector rotates to the fourth quadrant, exceeding the rotation range. Therefore, Figure 2F2 is used as the final execution path. The end effector can rotate to the second quadrant. From the perspective of an end effector with axisymmetric properties, such as a suction cup or a clamp, the two rotation methods eventually reach the same position. Therefore, the periodicity of the yaw angle is overcome and the problem of peripheral winding is prevented.

[0047] In this embodiment, by obtaining the preset size and direction values ​​of the peripheral wiring, and based on the first and second six-dimensional coordinates, the path of the end effector is planned using an inverse kinematics algorithm to obtain the rotation angle and direction of the wrist joint. Combined with the values ​​of the peripheral wiring, the final execution path is calculated, which avoids the problem of peripheral wiring of the end effector when the robot's flange is parallel to the ground and the end effector is axially symmetric, thereby reducing labor costs and improving work efficiency.

[0048] In some embodiments, it also includes:

[0049] Obtain the preset physical limit value, and calculate the torsion range by combining the physical limit value with the length and position of the peripheral wiring.

[0050] In this embodiment, by adding physical limit values, i.e. mechanical limit values, to the torsion range calculation, the physical over-limit of the end effector is prevented, thereby improving the accuracy of path planning.

[0051] In some embodiments, the first six-dimensional coordinates and the second six-dimensional coordinates of the collected material include:

[0052] The first and second six-dimensional coordinates of the material are collected from the host computer of the six-degree-of-freedom collaborative robot.

[0053] In this embodiment, the applicability of the method is improved.

[0054] In some embodiments, obtaining the preset physical limit value includes:

[0055] Physical limit values ​​are collected from sensors in the robot's wrist joint axis assembly.

[0056] In this embodiment, the applicability of the method is improved.

[0057] This application also provides a path planning device for a six-degree-of-freedom collaborative robot end effector. Please refer to [link to relevant documentation]. Figure 3 As shown, the device includes:

[0058] Data acquisition module 100 is used to acquire the first six-dimensional coordinates and the second six-dimensional coordinates of the material;

[0059] The coordinate system construction module 200 is used to construct a flange coordinate system, which is based on a flange parallel to the ground.

[0060] Peripheral module 300 is used to obtain the preset length and position of peripheral wiring, and calculate the torsion range based on the length and position of peripheral wiring. The length of peripheral wiring is the length of peripheral wiring, and the position is the position of the connection between the two ends of the peripheral wiring in the flange coordinate system.

[0061] The path planning module 400 is used to plan the path of the end effector based on the first six-dimensional coordinates and the second six-dimensional coordinates using an inverse kinematics algorithm, so as to obtain the rotation angle and rotation direction of the wrist joint, wherein the rotation direction is either clockwise or counterclockwise.

[0062] The selection module 500 is used to select the rotation angle and rotation direction as the final execution path when the rotation angle is within the torsion range, and to select the supplementary angle of the rotation angle and the opposite direction of the rotation direction as the final execution path when the rotation angle is not within the torsion range.

[0063] The functions of each module in the path planning device of the above-mentioned six-degree-of-freedom collaborative robot end effector correspond to the steps in the above-mentioned path planning method embodiment of the six-degree-of-freedom collaborative robot end effector, and their functions and implementation processes will not be described in detail here.

[0064] This application also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the path planning method for a six-degree-of-freedom collaborative robot end effector as described in any of the above embodiments.

[0065] This application also provides a computer-readable storage medium storing a program. The computer-readable storage medium refers to a data storage medium, which may include, but is not limited to, floppy disks, optical disks, hard disks, flash memory, USB flash drives, and / or Memory Sticks. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The working process, details, and technical effects of the computer-readable storage medium provided in this embodiment can be found in the above embodiment regarding a path planning method for a six-degree-of-freedom collaborative robot end effector, and will not be repeated here.

[0066] The application also provides a computer program product, including computer instructions that, when executed by a processor, implement the steps of the path planning method for a six-degree-of-freedom collaborative robot end effector as described in any of the above embodiments.

[0067] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM).

[0068] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. The above embodiments only illustrate several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A path planning method for the end effector of a six-degree-of-freedom collaborative robot, characterized in that, Applications include: end effectors with axisymmetric properties, including: Collect the first and second six-dimensional coordinates of the material; Construct a flange coordinate system, which is based on a flange parallel to the ground; Obtain the preset length and position of the peripheral wiring, and obtain the diameter, height and length of the end effector, wherein the end effector is an axisymmetric end effector; Based on the length and position of the peripheral wiring, and in conjunction with the diameter, height, and length of the end effector, the torsion range is calculated. The torsion range is the range of angles that the end effector can rotate to in the flange coordinate system. The length of the peripheral wiring is the length of the peripheral wiring itself. The position is the position of the line connecting the two ends of the peripheral wiring in the flange coordinate system. Based on the first and second six-dimensional coordinates, the path of the end effector is planned using an inverse kinematics algorithm to obtain the rotation angle and rotation direction of the wrist joint, wherein the rotation direction is either clockwise or counterclockwise. When the rotation angle is within the torsion range, the rotation angle and rotation direction are used as the final execution path; when the rotation angle is not within the torsion range, the supplementary angle of the rotation angle and the opposite direction of the rotation direction are used as the final execution path.

2. The path planning method for a six-degree-of-freedom collaborative robot end effector according to claim 1, characterized in that, Also includes: Obtain the preset physical limit value, and calculate the torsion range by combining the physical limit value with the length and position of the peripheral wiring.

3. The path planning method for the end effector of a six-degree-of-freedom collaborative robot according to claim 1, characterized in that, The torsion range is equal to 0° to 180°.

4. The path planning method for the end effector of a six-degree-of-freedom collaborative robot according to claim 1, characterized in that, The torsion range is equal to 0° to 360°.

5. The path planning method for the end effector of a six-degree-of-freedom collaborative robot according to claim 1, characterized in that, The first and second six-dimensional coordinates of the collected material include: The first and second six-dimensional coordinates of the material are collected from the host computer of the six-degree-of-freedom collaborative robot.

6. The path planning method for a six-degree-of-freedom collaborative robot end effector according to claim 2, characterized in that, The process of obtaining the preset physical limit value includes: Physical limit values ​​are collected from sensors in the robot's wrist joint axis assembly.

7. A path planning device for a six-degree-of-freedom collaborative robot end effector, characterized in that, Applications include: end effectors with axisymmetric properties, including: The data acquisition module is used to collect the first and second six-dimensional coordinates of the material. A coordinate system construction module is used to construct a flange coordinate system, which is based on a flange parallel to the ground. The peripheral module is used to obtain the preset length and position of the peripheral wiring, and to obtain the diameter, height and length of the end effector, wherein the end effector is an axisymmetric end effector; based on the length and position of the peripheral wiring, combined with the diameter, height and length of the end effector, the torsion range is calculated, wherein the torsion range is the range of angles to which the end effector can rotate in the flange coordinate system, the length of the peripheral wiring is the length of the peripheral wiring, and the position is the position of the line connecting the two ends of the peripheral wiring in the flange coordinate system; The path planning module is used to plan the path of the end effector based on the first six-dimensional coordinates and the second six-dimensional coordinates using an inverse kinematics algorithm, so as to obtain the rotation angle and rotation direction of the wrist joint, wherein the rotation direction is either clockwise or counterclockwise. The selection module is used to select the rotation angle and rotation direction as the final execution path when the rotation angle is within the torsion range, and to select the supplementary angle of the rotation angle and the opposite direction of the rotation direction as the final execution path when the rotation angle is not within the torsion range.

8. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the path planning method for the six-degree-of-freedom collaborative robot end effector as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a program, wherein when the program is executed by a processor, it implements the path planning method for a six-degree-of-freedom collaborative robot end effector as described in any one of claims 1 to 6.

10. A computer program product comprising computer instructions, characterized in that, When executed by a processor, the computer instructions implement the steps of the path planning method for the six-degree-of-freedom collaborative robot end effector as described in any one of claims 1 to 6.

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