Path planning method for end effector of six-degree-of-freedom collaborative robot

Abstract

The invention relates to the field of industrial robot control, in particular to a path planning method for an end effector of a six-degree-of-freedom collaborative robot, and the method comprises the steps: obtaining the length and position of a preset peripheral wiring, calculating to obtain a torsion range, and obtaining the path of the end effector of the six-degree-of-freedom collaborative robot based on a first six-dimensional coordinate and a second six-dimensional coordinate; the path of the end effector is planned by adopting an inverse kinematics algorithm, the rotation angle and the rotation direction of the wrist joint are obtained, and the final execution path is calculated by combining the torsion range, so that the problem of external winding of the end effector under the condition that a flange plate of the robot is parallel to the ground and the end effector is axisymmetric is avoided; the labor cost is reduced, and the operation efficiency is improved.

Description

Technical Field

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

[0002] A six-degree-of-freedom robot, also known as a six-axis robot, is a highly flexible industrial robot with six independent rotating joints that can adjust any position and posture in three-dimensional space. This type of robot is widely used in industrial automation fields such as welding, assembly, spraying, and handling, and is favored for its high precision, high efficiency, and flexibility. Whether in traditional dismantling and stacking work or other operations of six-degree-of-freedom robots controlled by conventional host computers, the end effector of the collaborative robot (manipulator, fixture, or suction cup, etc.) will always encounter a contradiction between the corresponding relationship between the axis angle and the yaw angle. Specifically, after the desired end position of the end effector of the robot is given, when the path of the end of the robot is planned by the inverse solution algorithm, the yaw angle of the robot is periodic, resulting in physical over-limit of the axis angle and peripheral winding of the end effector. The periodicity is due to the fact that the domain of the yaw angle is ±180°, so when the yaw angle changes from +180° to -180°, or from -180° to +180°, from the perspective of mathematics and physics, the direction of the robot end effector is the same.

[0003] The current method to solve the physical over-limit of axis angle and the peripheral winding of end effector is to manually add restrictions at the input and output 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 is too dependent on manpower, resulting in low operation efficiency; the restriction parameters are based on preset rules or simple pattern recognition settings, lacking in-depth analysis of the current status of robot operation, and therefore lacking flexibility and adaptability, that is, it is 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 robot's end effector from winding or axis group exceeding the limit is an urgent problem that needs to be solved. Summary of the invention

[0005] The present application provides a path planning method for the end effector of a six-degree-of-freedom collaborative robot. By acquiring the length and position of the peripheral wiring of the end effector, its torsion range is calculated, and combined with the axial symmetry of the end effector, the robot's operating path is intelligently calculated, avoiding the problems of physical over-limit of the end effector's axis group and peripheral winding when the robot's flange is parallel to the ground and the end effector is axially symmetrical.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

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

[0008] Collect the first six-dimensional coordinates and the second six-dimensional coordinates of the material;

[0009] Constructing a flange coordinate system, wherein the flange coordinate system is based on a flange parallel to the ground;

[0010] Obtaining a preset length and position of the peripheral wiring, and calculating a torsion range according to the length and position of the peripheral wiring, wherein the length of the peripheral wiring is the length of the peripheral wiring, and the position is the position of the connection line of the two end interfaces of the peripheral wiring in the flange coordinate system;

[0011] Based on the first six-dimensional coordinate and the second six-dimensional coordinate, an inverse kinematics algorithm is used to plan the path of the end effector to obtain a rotation angle and a rotation direction of the wrist joint, wherein the rotation direction is a clockwise direction or a counterclockwise direction;

[0012] When the rotation angle is within the torsion range, the rotation angle and the rotation direction are used as the final execution path; when the rotation angle is not within the torsion range, the complementary angle of the rotation angle and the opposite direction of the rotation direction are used as the final execution path.

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

[0014] A preset physical limit value is obtained, and the torsion range is calculated by combining the physical limit value with the length and position of the peripheral connection.

[0015] In a preferred example of the present application, it can be further configured that the torsion range is equal to 0° to 180°.

[0016] In a preferred example of the present application, it can be further configured that the torsion range is equal to 0° to 360°.

[0017] In a preferred example of the present application, it can be further configured that the first six-dimensional coordinate and the second six-dimensional coordinate of the collected material include:

[0018] The first six-dimensional coordinates and the second six-dimensional coordinates of the material are collected from the host computer of the six-degree-of-freedom collaborative robot.

[0019] In a preferred example of the present application, it can be further configured that the obtaining of a preset physical limit value includes:

[0020] The physical limit values ​​are collected from the sensors of the robot's wrist joint axis group.

[0021] In a second aspect, the present application provides a path planning device for an end effector of a six-degree-of-freedom collaborative robot, the device comprising:

[0022] A data acquisition module, used for acquiring the first six-dimensional coordinates and the second six-dimensional coordinates of the material;

[0023] A coordinate system building module, used to build a flange coordinate system, wherein the flange coordinate system is based on a flange parallel to the ground;

[0024] The peripheral module is used to obtain the length and position of the preset peripheral wiring, and calculate the torsion range according to the length and position of the peripheral wiring, wherein the length of the peripheral wiring is the length of the peripheral wiring, and the position is the position of the connection line of the two end interfaces of the peripheral wiring in the flange coordinate system;

[0025] A path planning module is used to plan the path of the end effector based on the first six-dimensional coordinate and the second six-dimensional coordinate by using an inverse kinematics algorithm to obtain a rotation angle and a rotation direction of the wrist joint, wherein the rotation direction is a clockwise direction or a counterclockwise direction;

[0026] A selection module is used to use the rotation angle and the rotation direction as the final execution path when the rotation angle is within the torsion range, and to use the complementary 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] In a third aspect, the present application provides a computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the path planning method for the end effector of a six-degree-of-freedom collaborative robot as described in any one of the above items are implemented.

[0028] In a fourth aspect, the present application provides a computer-readable storage medium having a program stored thereon, wherein when the program is executed by a processor, a path planning method for an end effector of a six-degree-of-freedom collaborative robot as described in any one of the above items is implemented.

[0029] In a fifth aspect, the present application provides a computer program product, comprising computer instructions, which, when executed by a processor, implement the steps of the path planning method for the end effector of a six-degree-of-freedom collaborative robot as described in any one of the above items.

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

[0031] The present application provides a path planning method for the end effector of a six-degree-of-freedom collaborative robot. The method obtains the length and position of the peripheral wiring of a preset end effector, calculates its torsion range, and plans the path of the end effector using an inverse kinematics algorithm based on the first six-dimensional coordinate and the second six-dimensional coordinate to obtain the rotation angle and rotation direction of the wrist joint. The final execution path is calculated in combination with the value of the peripheral wiring, thereby avoiding the problem of peripheral winding 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A flowchart of a path planning method for an end effector of a six-degree-of-freedom collaborative robot provided in one embodiment of the present application.

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

[0034] Figure 3 A structural diagram of a path planning device for an end effector of a six-degree-of-freedom collaborative robot provided in one embodiment of the present application. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0036] In one embodiment of the present application, a path planning method for an end effector of a six-degree-of-freedom collaborative robot is provided. Figure 1 As shown, the method includes:

[0037] S100: Collecting the first six-dimensional coordinates and the second six-dimensional coordinates of the 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 of which are six-dimensional coordinates;

[0039] S200: constructing a flange coordinate system, wherein the flange coordinate system takes the flange parallel to the ground as a reference;

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

[0041] S300: Obtaining a preset length and position of an external wiring, and calculating a torsion range according to the length and position of the external wiring, wherein the length of the external wiring is the length of the external wiring, and the position is the position of a connection line of two end interfaces of the external wiring in the flange coordinate system;

[0042] Specifically, the user first observes the peripheral wiring situation, and then sets the length and position of the peripheral wiring, which can be expressed as a vector. The method obtains this vector to obtain the preset length and position of the peripheral wiring. The direction of the peripheral wiring is the position of the connection line of the two end interfaces of the peripheral wiring in the flange coordinate system, which can be expressed in spatial coordinates, and the length is the length of the peripheral wiring. The torsion range is the angle range that the end effector can rotate to in the flange coordinate system, which can be calculated according to 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 coordinate and the second six-dimensional coordinate, an inverse kinematics algorithm is used to plan a path of the end effector to obtain a rotation angle and a rotation direction of the wrist joint, where the rotation direction is a clockwise direction or a counterclockwise direction;

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

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

[0046] Specifically, see Figure 2 As shown, the rotation angle obtained by the inverse kinematics algorithm is always the shortest path, such as Figure 2 Assuming the rotation range is the first and second quadrants, that is, 0° to 180°, the end effector rotates to the fourth quadrant after rotating in the direction of F1, which exceeds the rotation range. Figure 2F2 in the figure is used as the final execution path. The end effector can be rotated to the second quadrant. From the perspective of an end effector with axisymmetry, such as a suction cup or a fixture, the final position reached by the two rotation methods is the same. This overcomes the periodicity of the yaw angle and prevents the problem of peripheral winding.

[0047] In this embodiment, by obtaining the size and direction values ​​of the preset peripheral connections, 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, and the rotation angle and rotation direction of the wrist joint are obtained. The final execution path is calculated in combination with the value of the peripheral connections, which avoids the problem of peripheral winding of the end effector when the robot's flange is parallel to the ground and the end effector is axially symmetrical, reduces labor costs, and improves work efficiency.

[0048] In some embodiments, it also includes:

[0049] A preset physical limit value is obtained, and the torsion range is calculated by combining the physical limit value with the length and position of the peripheral connection.

[0050] In this embodiment, by adding a physical limit value, that is, a mechanical limit value, into the calculation of the torsion range, the physical over-limit of the end effector is prevented, thereby improving the accuracy of the 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 six-dimensional coordinates and the 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 a preset physical limit value includes:

[0055] The physical limit values ​​are collected from the sensors of the robot's wrist joint axis group.

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

[0057] This application also provides a path planning device for the end effector of a six-degree-of-freedom collaborative robot. Figure 3 As shown, the device comprises:

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

[0059] A coordinate system construction module 200 is used to construct a flange coordinate system, wherein the flange coordinate system is based on a flange parallel to the ground;

[0060] The peripheral module 300 is used to obtain the length and position of a preset peripheral wiring, and calculate the torsion range according to the length and position of the peripheral wiring, wherein the length of the peripheral wiring is the length of the peripheral wiring, and the position is the position of the connection line of the two end interfaces of the peripheral wiring in the flange coordinate system;

[0061] A path planning module 400 is used to plan the path of the end effector based on the first six-dimensional coordinate and the second six-dimensional coordinate by using an inverse kinematics algorithm to obtain a rotation angle and a rotation direction of the wrist joint, wherein the rotation direction is a clockwise direction or a counterclockwise direction;

[0062] The selection module 500 is used to use the rotation angle and the rotation direction as the final execution path when the rotation angle is within the torsion range, and use the complementary 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 functional implementation of each module in the path planning device of the above-mentioned six-degree-of-freedom collaborative robot end effector corresponds to the steps in the above-mentioned path planning method embodiment of the six-degree-of-freedom collaborative robot end effector, and its functions and implementation processes will not be repeated here one by one.

[0064] The present 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 when the processor executes the computer program, the steps of the path planning method for the end effector of a six-degree-of-freedom collaborative robot as described in any of the above embodiments are implemented.

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

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

[0067] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in the present 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. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0068] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above-mentioned embodiments only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several deformations and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of this application shall be based on the attached claims.

Claims

1. A path planning method for an end effector of a six-degree-of-freedom collaborative robot, characterized in that: include: Collect the first six-dimensional coordinates and the second six-dimensional coordinates of the material; Constructing a flange coordinate system, wherein the flange coordinate system is based on a flange parallel to the ground; Obtaining a preset length and position of the peripheral wiring, and calculating a torsion range according to the length and position of the peripheral wiring, wherein the length of the peripheral wiring is the length of the peripheral wiring, and the position is the position of the connection line of the two end interfaces of the peripheral wiring in the flange coordinate system; Based on the first six-dimensional coordinate and the second six-dimensional coordinate, an inverse kinematics algorithm is used to plan the path of the end effector to obtain a rotation angle and a rotation direction of the wrist joint, wherein the rotation direction is a clockwise direction or a counterclockwise direction; When the rotation angle is within the torsion range, the rotation angle and the rotation direction are used as the final execution path; when the rotation angle is not within the torsion range, the complementary 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 the end effector of a six-degree-of-freedom collaborative robot according to claim 1, characterized in that: Also includes: A preset physical limit value is obtained, and the torsion range is calculated by combining the physical limit value with the length and position of the peripheral connection.

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 six-dimensional coordinate and the second six-dimensional coordinate of the collected material include: The first six-dimensional coordinates and the 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 the end effector of a six-degree-of-freedom collaborative robot according to claim 2, characterized in that: The step of obtaining a preset physical limit value includes: The physical limit values ​​are collected from the sensors of the robot's wrist joint axis group.

7. A path planning device for an end effector of a six-degree-of-freedom collaborative robot, characterized in that: include: A data acquisition module, used for acquiring the first six-dimensional coordinates and the second six-dimensional coordinates of the material; A coordinate system building module, used to build a flange coordinate system, wherein the flange coordinate system is based on a flange parallel to the ground; The peripheral module is used to obtain the length and position of the preset peripheral wiring, and calculate the torsion range according to the length and position of the peripheral wiring, wherein the length of the peripheral wiring is the length of the peripheral wiring, and the position is the position of the connection line of the two end interfaces of the peripheral wiring in the flange coordinate system; A path planning module is used to plan the path of the end effector based on the first six-dimensional coordinate and the second six-dimensional coordinate by using an inverse kinematics algorithm to obtain a rotation angle and a rotation direction of the wrist joint, wherein the rotation direction is a clockwise direction or a counterclockwise direction; A selection module is used to use the rotation angle and the rotation direction as the final execution path when the rotation angle is within the torsion range, and to use the complementary 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, the steps of the path planning method for the end effector of a six-degree-of-freedom collaborative robot are implemented 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 the processor, the path planning method for the end effector of a six-degree-of-freedom collaborative robot according to any one of claims 1 to 6 is implemented.

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 end effector of a six-degree-of-freedom collaborative robot as described in claims 1 to 6.

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