Mechanical arm universal arc instruction position and posture transition synchronous planning method and system

Abstract

The invention discloses a mechanical arm general arc instruction position and posture transition synchronous planning method and system.The method comprises the steps that the circle center and the radius are determined based on user data, and the user data comprise a starting point, an ending point and a space reference point; a target arc is obtained based on the spatial reference point and the circle center, and the target arc is proportionally divided to obtain different arc lengths; determining a synchronization condition, specifically including obtaining a transition starting point and a transition ending point by multiplying a set transition section parameter with different arc lengths; and curve speed planning is conducted according to the total arc length of the arcs, position and posture values are determined according to the interpolation points, and a joint control command of the robotic arm is generated based on the position and posture values. According to the method, high-order smoothness of attitude transition can be realized based on geometric characteristic interpolation, dynamic adjustment and no additional design of attitude interpolation, and attitude change is associated with arc length parameters of an arc path through synchronous mapping, so that attitude transition is more natural, and abrupt rotation is avoided.

Description

Technical Field

[0001] The present invention relates to the field of robot control technology, and more specifically, to a method and system for synchronously planning the position and posture transition of a general arc instruction of a robot arm. Background Art

[0002] In the field of motion control of robots and manipulators, arc command planning is an important part of achieving synchronous control of complex trajectories and postures. Arc motion is usually used by industrial robots for welding, gluing, cutting and other applications, requiring the end of the manipulator to move along an arc trajectory, and the posture changes must be synchronized with the position.

[0003] At present, the use scheme in the prior art is as follows: 1. Use geometric relationships to directly calculate arc paths. Usually, the arc trajectory is determined by knowing the starting point, end point, and reference point, and then the rotation matrix or quaternion is used to describe the posture. Advantages: simple calculation, direct use of the mathematical properties of the arc, high calculation efficiency, and easy implementation. It is suitable for regular arc paths with fixed center and radius. At the same time, there are obvious disadvantages, namely, the posture planning is not flexible, and the interpolation of the posture often requires additional design, which may lead to uneven posture transition, lack of dynamic optimization, and inability to handle speed and acceleration constraints well. 2. Generate continuous and smooth paths and postures through spline interpolation or parameterization methods. Among them, Euler angle interpolation or quaternion interpolation is often used for posture interpolation. The advantages are good smoothness, good continuity and smoothness of position and posture on the trajectory, high flexibility, and support for the planning of complex trajectories and diverse postures. There are also obvious disadvantages, namely, high computational complexity, interpolation calculation requires more resources, especially in scenarios with high real-time requirements, and possible distortion. When the number of key points is insufficient or the distribution is unreasonable, it may cause path distortion or posture error. Summary of the invention

[0004] The purpose of the present invention is to provide a method and system for synchronous planning of general arc command position and posture transition of a robotic arm, which is based on geometric characteristic interpolation and can be dynamically adjusted without the need for additional design of posture interpolation. It can also achieve high-order smoothness of posture transition. Through synchronous mapping, the change of posture is associated with the arc length parameter of the arc path, making the posture transition more natural without abrupt rotation.

[0005] A first aspect of the present invention provides a method for synchronously planning a general arc command position and posture transition of a robotic arm, comprising the following steps: Determine the center and radius of the circle based on user data, wherein the user data includes a start point, an end point, and a spatial reference point; A target arc is obtained based on the spatial reference point combined with the center of the circle, and the target arc is proportionally divided to obtain different arc lengths; Determine the synchronization conditions, specifically including obtaining the set transition segment parameters and multiplying them by different arc lengths to obtain the transition start point and transition end point; The curve speed is planned according to the total arc length, and the position and attitude values ​​are determined according to the interpolation points, and the joint control commands of the robot arm are generated based on the position and attitude values.

[0006] In this solution, the center and radius of the circle are determined based on user data, wherein the user data includes a starting point, an end point, and a spatial reference point, specifically including: Get spatial reference points P1, P2, and P3, where P1: (x1, y1, z1, a1, b1, c1), P2: (x2, y2, z2, a2, b2, c2), and P3: (x3, y3, z3, a3, b3, c3); Determine the plane and the plane normal vector based on the spatial reference points P1, P2 and P3; After the plane is determined, the center of the circle is obtained by combining equidistance constraints and plane constraints, and the radius is calculated simultaneously.

[0007] In this solution, the target arc is obtained based on the spatial reference point combined with the center of the circle, and the target arc is proportionally divided to obtain different arc lengths, specifically including: Calculate the attitude difference of spatial reference points P1, P2 and P3 to obtain the synchronous planning value; The target arc obtained by the spatial reference points P1, P2 and P3 and the center of the circle is divided into different arc lengths based on different positions, wherein the segment of the spatial reference points P1 and P2 is arcL1, and the segment of the spatial reference points P2 and P3 is arcL2.

[0008] In this solution, the synchronization condition is determined by obtaining the set transition segment parameters and multiplying them by different arc lengths to obtain the transition start point and transition end point, which specifically includes: Get the blend-ratio parameter of the transition segment, which is a value in the interval [0,1] and the maximum length does not exceed half of the shortest arc length of the two arc lengths; The different arc lengths are multiplied by the transition segment parameter blend-ratio to obtain arc length positions corresponding to the transition start point and the transition end point.

[0009] In this solution, the curve speed is planned according to the total arc length, and the position and attitude values ​​are determined according to the interpolation points. The joint control commands of the robot arm are generated based on the position and attitude values, which specifically include: Performing S-curve velocity planning according to the total arc length to determine a displacement function and a velocity function; Determine the interpolation point corresponding to the total arc length of the arc based on the displacement function and the speed function; Based on the interpolation points, position and posture synchronous proportional mapping movement is performed to obtain the position and posture values ​​for interpolation movement, wherein the position and posture values ​​are specifically decomposed into different joint control commands corresponding to the current robot arm to control the movement of the robot arm.

[0010] In this solution, the method further includes connecting two transition segments of arc length by a fifth-order polynomial during the interpolation point movement process, wherein the fifth-order polynomial is as follows: x(t)= a_0 + a_1 t + a_2 t^2 + a_3 t^3 + a_4 t^4 + a_5 t^5; Where x(t) is the displacement at time t; a_0, a_1, a_2, a_3, a_4, a_5 are the coefficients of the polynomial, and t is time.

[0011] The second aspect of the present invention further provides a system for synchronous planning of general circular arc instruction position and attitude transition of a robot arm, comprising a memory and a processor, wherein the memory comprises a method program for synchronous planning of general circular arc instruction position and attitude transition of a robot arm, and when the method program for synchronous planning of general circular arc instruction position and attitude transition of a robot arm is executed by the processor, the following steps are implemented: Determine the center and radius of the circle based on user data, wherein the user data includes a start point, an end point, and a spatial reference point; A target arc is obtained based on the spatial reference point combined with the center of the circle, and the target arc is proportionally divided to obtain different arc lengths; Determine the synchronization conditions, specifically including obtaining the set transition segment parameters and multiplying them by different arc lengths to obtain the transition start point and transition end point; The curve speed is planned according to the total arc length, and the position and attitude values ​​are determined according to the interpolation points, and the joint control commands of the robot arm are generated based on the position and attitude values.

[0012] In this solution, the center and radius of the circle are determined based on user data, wherein the user data includes a starting point, an end point, and a spatial reference point, specifically including: Get spatial reference points P1, P2, and P3, where P1: (x1, y1, z1, a1, b1, c1), P2: (x2, y2, z2, a2, b2, c2), and P3: (x3, y3, z3, a3, b3, c3); Determine the plane and the plane normal vector based on the spatial reference points P1, P2 and P3; After the plane is determined, the center of the circle is obtained by combining equidistance constraints and plane constraints, and the radius is calculated simultaneously.

[0013] In this solution, the target arc is obtained based on the spatial reference point combined with the center of the circle, and the target arc is proportionally divided to obtain different arc lengths, specifically including: Calculate the attitude difference of spatial reference points P1, P2 and P3 to obtain the synchronous planning value; The target arc obtained by the spatial reference points P1, P2 and P3 and the center of the circle is divided into different arc lengths based on different positions, wherein the segment between the spatial reference points P1 and P2 is arcL1, and the segment between the spatial reference points P2 and P3 is arcL2.

[0014] In this solution, the synchronization condition is determined by obtaining the set transition segment parameters and multiplying them by different arc lengths to obtain the transition start point and transition end point, which specifically includes: Get the blend-ratio parameter of the transition segment, which is a value in the interval [0,1] and the maximum length does not exceed half of the shortest arc length of the two arc lengths; The different arc lengths are multiplied by the transition segment parameter blend-ratio to obtain arc length positions corresponding to the transition start point and the transition end point.

[0015] In this solution, the curve speed is planned according to the total arc length, and the position and attitude values ​​are determined according to the interpolation points. The joint control commands of the robot arm are generated based on the position and attitude values, which specifically include: Performing S-curve velocity planning according to the total arc length to determine a displacement function and a velocity function; Determine the interpolation point corresponding to the total arc length of the arc based on the displacement function and the speed function; Based on the interpolation points, position and posture synchronous proportional mapping movement is performed to obtain the position and posture values ​​for interpolation movement, wherein the position and posture values ​​are specifically decomposed into different joint control commands corresponding to the current robot arm to control the movement of the robot arm.

[0016] In this solution, the method further includes connecting two transition segments of arc length by a fifth-order polynomial during the interpolation point movement process, wherein the fifth-order polynomial is as follows: x(t)= a_0 + a_1 t + a_2 t^2 + a_3 t^3 + a_4 t^4 + a_5 t^5; Where x(t) is the displacement at time t; a_0, a_1, a_2, a_3, a_4, a_5 are the coefficients of the polynomial, and t is time.

[0017] The third aspect of the present invention provides a computer-readable storage medium, which includes a general circular arc command position and posture transition synchronization planning method program for a machine robot arm. When the general circular arc command position and posture transition synchronization planning method program for a machine robot arm is executed by a processor, the steps of a general circular arc command position and posture transition synchronization planning method for a machine robot arm as described in any one of the above items are implemented.

[0018] The present invention discloses a method and system for synchronously planning the position and attitude transition of a general circular arc instruction of a robotic arm. The method and system are based on geometric characteristic interpolation and can be adjusted dynamically. No additional design of attitude interpolation is required. High-order smoothness of attitude transition can be achieved. The calculation is simple and does not require much additional computing power.

[0019] Among them, through synchronous mapping, the change of posture is associated with the arc length parameter of the arc path, making the posture transition more natural without abrupt rotation. Synchronous mapping can ensure the continuity of the first-order, second-order and even higher-order derivatives of position and posture on the path, and improve the overall smoothness of the trajectory.

[0020] In addition, the movement is highly coordinated. Through mapping, the changes in posture and position are directly related, avoiding the problem of posture not following after the path is completed. It allows the speed of posture changes with the path to be adjusted proportionally to adapt to different task requirements. For example, increasing the speed of posture changes at key points can ensure that the relationship between posture and position remains consistent throughout the entire arc trajectory, and local incoordination is less likely to occur. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A flowchart of a method for synchronously planning the position and posture transition of a general arc instruction of a robot arm according to the present invention is shown; Figure 2 A block diagram of a system for synchronously planning the position and posture transition of a general circular arc instruction of a robot arm according to the present invention is shown. DETAILED DESCRIPTION

[0022] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0023] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0024] Figure 1A flow chart of a method for synchronously planning the position and posture transition of a general arc instruction of a robot arm of the present application is shown.

[0025] like Figure 1 As shown, the present application discloses a method for synchronously planning the position and attitude transition of a general arc instruction of a robotic arm, comprising the following steps: S102, determining a center and a radius of a circle based on user data, wherein the user data includes a start point, an end point, and a spatial reference point; S104, obtaining a target arc based on the spatial reference point combined with the center of the circle, and dividing the target arc into different arc lengths; S106, determining synchronization conditions, specifically including obtaining a set transition segment parameter and multiplying it by different arc lengths to obtain a transition start point and a transition end point; S108, performing curve velocity planning according to the total arc length, determining the position and attitude values ​​according to the interpolation points, and generating joint control commands for the robot arm based on the position and attitude values.

[0026] It should be noted that in this embodiment, the center and radius of the circle are determined specifically according to the starting point, the end point and the reference space point, so as to calculate the arc line and directly generate the arc trajectory. The arc length and the attitude difference are proportionally distributed, and then the generated position interpolation ratio is synchronized to the attitude planning and presented in the form of Euler angles. Under the conditions of limited examples, good position and attitude synchronization can be achieved, and the attitude transition with non-zero speed can be achieved.

[0027] Specifically, the center and radius are first determined based on user data, wherein the user data includes a starting point, an end point, and a spatial reference point provided by the user, wherein the number of spatial reference points is at least three. Accordingly, in this embodiment, there are three spatial reference points P1, P2, and P3, a plane is determined by these three points, and then the center and radius are calculated from the determined plane.

[0028] Furthermore, a target arc is obtained based on the spatial reference point combined with the center of the circle, the target arc is proportionally divided to obtain different arc lengths, and synchronization conditions are determined, specifically including obtaining the set transition segment parameters and multiplying them with different arc lengths to obtain a transition start point and a transition end point. Finally, curve speed planning is performed according to the total arc length, and the position and attitude values ​​are determined according to the interpolation points, and joint control commands for the robot arm are generated based on the position and attitude values.

[0029] According to an embodiment of the present invention, the determining of the center and radius based on user data, wherein the user data includes a starting point, an end point, and a spatial reference point, specifically includes: Get spatial reference points P1, P2, and P3, where P1: (x1, y1, z1, a1, b1, c1), P2: (x2, y2, z2, a2, b2, c2), and P3: (x3, y3, z3, a3, b3, c3); Determine the plane and the plane normal vector based on the spatial reference points P1, P2 and P3; After the plane is determined, the center of the circle is obtained by combining equidistance constraints and plane constraints, and the radius is calculated simultaneously.

[0030] It should be noted that, in this embodiment, when a plane is determined by three spatial reference points P1, P2 and P3, a plane normal vector is first determined, wherein the plane normal vector is obtained by the difference product of two vectors, as follows: ; Among them, n=((y2-y1)×(z3-z1)-(z2-z1)×(y3-y1), (z2-z1)×(x3-x1)-(x2-x1)×(z3-z1), (x2-x1)×(y3-y1)-(y2-y1)×(x3-x1)); Correspondingly, the obtained plane equation is: nx(x-x1)+ny(y-y1)+nz(z-z1)=0. After the plane is determined, the center of the circle is obtained by jointly constraining equidistance constraints and plane constraints, and the radius is calculated simultaneously.

[0031] According to an embodiment of the present invention, obtaining a target arc based on a spatial reference point combined with the center of the circle, and dividing the target arc proportionally to obtain different arc lengths specifically includes: Calculate the attitude difference of spatial reference points P1, P2 and P3 to obtain the synchronous planning value; The target arc obtained by the spatial reference points P1, P2 and P3 and the center of the circle is divided into different arc lengths based on different positions, wherein the segment between the spatial reference points P1 and P2 is arcL1, and the segment between the spatial reference points P2 and P3 is arcL2.

[0032] It should be noted that, in this embodiment, the posture differences of the spatial reference points P1, P2 and P3 are calculated. , , select the largest value among the three attitude differences as the synchronization planning value, and divide the arc generated by the position into proportions, such as arcL1 for the p1-p2 segment, arcL2 for the p2-p3 segment, and the total arc length is arcL=arcL1 + arcL2.

[0033] According to an embodiment of the present invention, the determining of the synchronization condition specifically includes obtaining a set transition segment parameter and multiplying it by different arc lengths to obtain a transition start point and a transition end point, specifically including: Get the blend-ratio parameter of the transition segment, which is a value in the interval [0,1] and the maximum length does not exceed half of the shortest arc length of the two arc lengths; The different arc lengths are multiplied by the transition segment parameter blend-ratio to obtain arc length positions corresponding to the transition start point and the transition end point.

[0034] It should be noted that in this embodiment, in order to meet the synchronization conditions of position and posture, certain conditions need to be met during planning. By obtaining the set transition segment parameter blend-ratio, specifically the value in the [0,1] interval, the maximum length is set to not exceed half of the shortest arc length of the two arc lengths. Then, by multiplying the different arc lengths with the blend-ratio, the arc length positions of the transition starting point and the transition ending point can be obtained to provide data support for subsequent planning.

[0035] According to an embodiment of the present invention, curve velocity planning is performed according to the total arc length, and the position and attitude values ​​are determined according to the interpolation points, and the joint control commands of the robot arm are generated based on the position and attitude values, which specifically includes: Performing S-curve velocity planning according to the total arc length to determine a displacement function and a velocity function; Determine the interpolation point corresponding to the total arc length of the arc based on the displacement function and the speed function; Based on the interpolation points, position and posture synchronous proportional mapping movement is performed to obtain the position and posture values ​​for interpolation movement, wherein the position and posture values ​​are specifically decomposed into different joint control commands corresponding to the current robot arm to control the movement of the robot arm.

[0036] It should be noted that, in this embodiment, the scheme is mainly based on position planning, supplemented by posture synchronization planning. S-curve speed planning is performed according to the total arc length of the arc, wherein S-curve speed planning is a speed control method commonly used in robotic arms, robots, automation systems and vehicle path planning. Its main advantage is that it can provide a smooth acceleration and deceleration process, reduce the vibration and stress of the mechanical system, and optimize the smoothness of the movement. Specifically, S-curve speed planning avoids the instantaneous changes that may be caused by traditional linear acceleration and deceleration planning by adopting smooth acceleration and deceleration curves (acceleration and deceleration change in an S shape on the time axis). This smooth transition method can significantly reduce the vibration and irregular inertial force of the mechanical system, making the movement smoother. In practical applications, it can perform tasks such as precise grasping, welding, spraying, and cutting.

[0037] Specifically, the displacement function and the velocity function are prior arts, which are only used in this embodiment and are not described in detail. It should be noted that the displacement function is as follows: ; ; The speed function is as follows: ; in, represents the initial speed, J represents the agility, a represents the acceleration, v represents the maximum speed, and T represents the movement time of each segment. Indicates the first exercise time. Indicates the second exercise time. Indicates the third exercise time. Indicates the fourth exercise time. Indicates the fifth exercise time. Indicates the sixth exercise time. Indicates the seventh exercise time.

[0038] Furthermore, the interpolation point corresponding to the total arc length is determined based on the displacement function and the velocity function, and the position and posture synchronous proportional mapping movement is performed according to the interpolation point. For example, the arc length interpolation value at a certain moment is Δs, and the interpolation value is compared with arcL1. If it is greater than, it means that the movement is to the p2-p3 arc segment at this time, otherwise it means that the movement is to the p1-p2 arc segment. If this is defined as the first arc segment, the ratio Δs / (arcL1) is calculated to obtain the ratio of the interpolation value to the p1-p2 arc segment arcL1, and it is synchronously mapped to Δθ / , where Δθ is the attitude interpolation value corresponding to the arc interpolation value, which can ensure the synchronous movement of position and attitude. At this time, the interpolation movement continues. When it reaches the transition section, the interpolation speed, acceleration and interpolation attitude value of the starting point of the transition section are obtained, and the position interpolation speed, acceleration and interpolation attitude value at the end of the transition are calculated.

[0039] According to an embodiment of the present invention, the method further includes connecting two transition segments of arc length by a fifth-order polynomial during the interpolation point motion process, wherein the fifth-order polynomial is as follows: x(t)= a_0 + a_1 t + a_2 t^2 + a_3 t^3 + a_4 t^4 + a_5 t^5; Where x(t) is the displacement at time t; a_0, a_1, a_2, a_3, a_4, a_5 are the coefficients of the polynomial, and t is time.

[0040] It should be noted that in this embodiment, the transition segment is connected by quintic polynomial planning. The purpose is to solve the problem of attitude speed jump at the connection point between the two arc lengths and the two attitudes in the proportional mapping. The speed and acceleration can be connected without jumps through polynomial connection. Among them, the quintic polynomial is widely used in motion planning, which can simultaneously control the starting and end constraints of displacement, velocity and acceleration, and is suitable for trajectory planning that requires smooth transition.

[0041] Specifically, the general form of the quintic polynomial is as follows: x(t)= a_0 + a_1 t + a_2 t^2 + a_3 t^3 + a_4 t^4 + a_5 t^5; Where: x(t) is the displacement at a certain time t; a_0, a_1, a_2, a_3, a_4, a_5 are the coefficients of the polynomial, and t is time. Further, the transition segment is connected through a quintic polynomial and the interpolation position and interpolation posture are output, which can smoothly transition to the second arc length and the second posture. Then, according to (Δs-arcL1) / (arcL2), the ratio of the interpolation value to the p2-p3 arc arcL2 is obtained, and synchronously mapped to Δθ / , where Δθ is the attitude interpolation value corresponding to the arc interpolation value. Until the entire arc motion is completed, the attitude motion also stops accordingly.

[0042] Figure 2 A block diagram of a system for synchronously planning the position and posture transition of a general circular arc instruction of a robot arm according to the present invention is shown.

[0043] like Figure 2 As shown, the present invention discloses a system for synchronous planning of general circular arc instruction position and attitude transition of a robot arm, comprising a memory and a processor, wherein the memory comprises a method program for synchronous planning of general circular arc instruction position and attitude transition of a robot arm, and when the method program for synchronous planning of general circular arc instruction position and attitude transition of a robot arm is executed by the processor, the following steps are implemented: Determine the center and radius of the circle based on user data, wherein the user data includes a start point, an end point, and a spatial reference point; A target arc is obtained based on the spatial reference point combined with the center of the circle, and the target arc is proportionally divided to obtain different arc lengths; Determine the synchronization conditions, specifically including obtaining the set transition segment parameters and multiplying them by different arc lengths to obtain the transition start point and transition end point; The curve speed is planned according to the total arc length, and the position and attitude values ​​are determined according to the interpolation points, and the joint control commands of the robot arm are generated based on the position and attitude values.

[0044] It should be noted that in this embodiment, the center and radius of the circle are determined specifically according to the starting point, the end point and the reference space point, so as to calculate the arc line and directly generate the arc trajectory. The arc length and the attitude difference are proportionally distributed, and then the generated position interpolation ratio is synchronized to the attitude planning and presented in the form of Euler angles. Under the conditions of limited examples, good position and attitude synchronization can be achieved, and the attitude transition with non-zero speed can be achieved.

[0045] Specifically, the center and radius are first determined based on user data, wherein the user data includes a starting point, an end point, and a spatial reference point provided by the user, wherein the number of spatial reference points is at least three. Accordingly, in this embodiment, there are three spatial reference points P1, P2, and P3, a plane is determined by these three points, and then the center and radius are calculated from the determined plane.

[0046] Furthermore, a target arc is obtained based on the spatial reference point combined with the center of the circle, the target arc is proportionally divided to obtain different arc lengths, and synchronization conditions are determined, specifically including obtaining the set transition segment parameters and multiplying them with different arc lengths to obtain a transition start point and a transition end point. Finally, curve speed planning is performed according to the total arc length, and the position and attitude values ​​are determined according to the interpolation points, and joint control commands for the robot arm are generated based on the position and attitude values.

[0047] According to an embodiment of the present invention, the determining of the center and radius based on user data, wherein the user data includes a starting point, an end point, and a spatial reference point, specifically includes: Get spatial reference points P1, P2, and P3, where P1: (x1, y1, z1, a1, b1, c1), P2: (x2, y2, z2, a2, b2, c2), and P3: (x3, y3, z3, a3, b3, c3); Determine the plane and the plane normal vector based on the spatial reference points P1, P2 and P3; After the plane is determined, the center of the circle is obtained by combining equidistance constraints and plane constraints, and the radius is calculated simultaneously.

[0048] It should be noted that, in this embodiment, when a plane is determined by three spatial reference points P1, P2 and P3, a plane normal vector is first determined, wherein the plane normal vector is obtained by the difference product of two vectors, as follows: ; Among them, n=((y2-y1)×(z3-z1)-(z2-z1)×(y3-y1), (z2-z1)×(x3-x1)-(x2-x1)×(z3-z1), (x2-x1)×(y3-y1)-(y2-y1)×(x3-x1)); Correspondingly, the obtained plane equation is: nx(x-x1)+ny(y-y1)+nz(z-z1)=0. After the plane is determined, the center of the circle is obtained by jointly constraining equidistance constraints and plane constraints, and the radius is calculated simultaneously.

[0049] According to an embodiment of the present invention, obtaining a target arc based on a spatial reference point combined with the center of the circle, and dividing the target arc proportionally to obtain different arc lengths specifically includes: Calculate the attitude difference of spatial reference points P1, P2 and P3 to obtain the synchronous planning value; The target arc obtained by the spatial reference points P1, P2 and P3 and the center of the circle is divided into different arc lengths based on different positions, wherein the segment between the spatial reference points P1 and P2 is arcL1, and the segment between the spatial reference points P2 and P3 is arcL2.

[0050] It should be noted that, in this embodiment, the posture differences of the spatial reference points P1, P2 and P3 are calculated. , , select the largest value among the three attitude differences as the synchronization planning value, and divide the arc generated by the position into proportions, such as the p1-p2 segment is arcL1, the p2-p3 segment is arcL2, and the total arc length is arcL=arcL1+arcL2.

[0051] According to an embodiment of the present invention, the determining of the synchronization condition specifically includes obtaining a set transition segment parameter and multiplying it by different arc lengths to obtain a transition start point and a transition end point, specifically including: Get the blend-ratio parameter of the transition segment, which is a value in the interval [0,1] and the maximum length does not exceed half of the shortest arc length of the two arc lengths; The different arc lengths are multiplied by the transition segment parameter blend-ratio to obtain arc length positions corresponding to the transition start point and the transition end point.

[0052] It should be noted that in this embodiment, in order to meet the synchronization conditions of position and posture, certain conditions need to be met during planning. By obtaining the set transition segment parameter blend-ratio, specifically the value in the [0,1] interval, the maximum length is set to not exceed half of the shortest arc length of the two arc lengths. Then, by multiplying the different arc lengths with the blend-ratio, the arc length positions of the transition starting point and the transition ending point can be obtained to provide data support for subsequent planning.

[0053] According to an embodiment of the present invention, curve velocity planning is performed according to the total arc length, and the position and attitude values ​​are determined according to the interpolation points, and the joint control commands of the robot arm are generated based on the position and attitude values, which specifically includes: Performing S-curve velocity planning according to the total arc length to determine a displacement function and a velocity function; Determine the interpolation point corresponding to the total arc length of the arc based on the displacement function and the speed function; Based on the interpolation points, position and posture synchronous proportional mapping movement is performed to obtain the position and posture values ​​for interpolation movement, wherein the position and posture values ​​are specifically decomposed into different joint control commands corresponding to the current robot arm to control the movement of the robot arm.

[0054] It should be noted that, in this embodiment, the scheme is mainly based on position planning, supplemented by posture synchronization planning. S-curve speed planning is performed according to the total arc length of the arc, wherein S-curve speed planning is a speed control method commonly used in robotic arms, robots, automation systems and vehicle path planning. Its main advantage is that it can provide a smooth acceleration and deceleration process, reduce the vibration and stress of the mechanical system, and optimize the smoothness of the movement. Specifically, S-curve speed planning avoids the instantaneous changes that may be caused by traditional linear acceleration and deceleration planning by adopting smooth acceleration and deceleration curves (acceleration and deceleration change in an S shape on the time axis). This smooth transition method can significantly reduce the vibration and irregular inertial force of the mechanical system, making the movement smoother. In practical applications, it can perform tasks such as precise grasping, welding, spraying, and cutting.

[0055] Specifically, the displacement function and the velocity function are prior arts, which are only used in this embodiment and are not described in detail. It should be noted that the displacement function is as follows: ; ; The speed function is as follows: ; in, represents the initial speed, J represents the agility, a represents the acceleration, v represents the maximum speed, and T represents the movement time of each segment. Indicates the first exercise time. Indicates the second exercise time. Indicates the third exercise time. Indicates the fourth exercise time. Indicates the fifth exercise time. Indicates the sixth exercise time. Indicates the seventh exercise time.

[0056] Furthermore, the interpolation point corresponding to the total arc length is determined based on the displacement function and the velocity function, and the position and posture synchronous proportional mapping movement is performed according to the interpolation point. For example, the arc length interpolation value at a certain moment is Δs, and the interpolation value is compared with arcL1. If it is greater than, it means that the movement is to the p2-p3 arc segment at this time, otherwise it means that the movement is to the p1-p2 arc segment. If this is defined as the first arc segment, the ratio Δs / (arcL1) is calculated to obtain the ratio of the interpolation value to the p1-p2 arc segment arcL1, and it is synchronously mapped to Δθ / , where Δθ is the attitude interpolation value corresponding to the arc interpolation value, which can ensure the synchronous movement of position and attitude. At this time, the interpolation movement continues. When it reaches the transition section, the interpolation speed, acceleration and interpolation attitude value of the starting point of the transition section are obtained, and the position interpolation speed, acceleration and interpolation attitude value at the end of the transition are calculated.

[0057] According to an embodiment of the present invention, the method further includes connecting two transition segments of arc length by a fifth-order polynomial during the interpolation point motion process, wherein the fifth-order polynomial is as follows: x(t)= a_0 + a_1 t + a_2 t^2 + a_3 t^3 + a_4 t^4 + a_5 t^5; Where x(t) is the displacement at time t; a_0, a_1, a_2, a_3, a_4, a_5 are the coefficients of the polynomial, and t is time.

[0058] It should be noted that in this embodiment, the transition segment is connected by quintic polynomial planning. The purpose is to solve the problem of attitude speed jump at the connection point between the two arc lengths and the two attitudes in the proportional mapping. The speed and acceleration can be connected without jumps through polynomial connection. Among them, the quintic polynomial is widely used in motion planning, which can simultaneously control the starting and end constraints of displacement, velocity and acceleration, and is suitable for trajectory planning that requires smooth transition.

[0059] Specifically, the general form of the quintic polynomial is as follows: x(t)= a_0 + a_1 t + a_2 t^2 + a_3 t^3 + a_4 t^4 + a_5 t^5; Where: x(t) is the displacement at a certain time t; a_0, a_1, a_2, a_3, a_4, a_5 are the coefficients of the polynomial, and t is time. Further, the transition segment is connected through a quintic polynomial and the interpolation position and interpolation posture are output, which can smoothly transition to the second arc length and the second posture. Then, according to (Δs-arcL1) / (arcL2), the ratio of the interpolation value to the p2-p3 arc arcL2 is obtained, and synchronously mapped to Δθ / , where Δθ is the attitude interpolation value corresponding to the arc interpolation value. Until the entire arc motion is completed, the attitude motion also stops accordingly.

[0060] The third aspect of the present invention provides a computer-readable storage medium, which includes a method program for synchronously planning the position and attitude transition of a general arc instruction for a robot arm. When the method program for synchronously planning the position and attitude transition of a general arc instruction for a robot arm is executed by a processor, the steps of a method for synchronously planning the position and attitude transition of a general arc instruction for a robot arm as described in any one of the above items are implemented.

[0061] The present invention discloses a method and system for synchronously planning the position and attitude transition of a general circular arc instruction of a robotic arm. The method and system are based on geometric characteristic interpolation and can be adjusted dynamically. No additional design of attitude interpolation is required. High-order smoothness of attitude transition can be achieved. The calculation is simple and does not require much additional computing power.

[0062] Among them, through synchronous mapping, the change of posture is associated with the arc length parameter of the arc path, making the posture transition more natural without abrupt rotation. Synchronous mapping can ensure the continuity of the first-order, second-order and even higher-order derivatives of position and posture on the path, and improve the overall smoothness of the trajectory.

[0063] In addition, the movement is highly coordinated. Through mapping, the changes in posture and position are directly related, avoiding the problem of posture not following after the path is completed. It allows the speed of posture changes with the path to be adjusted proportionally to adapt to different task requirements. For example, increasing the speed of posture changes at key points can ensure that the relationship between posture and position remains consistent throughout the entire arc trajectory, and local incoordination is less likely to occur.

[0064] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0065] The units described above as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units; they may be located in one place or distributed on multiple network units; some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0066] In addition, all functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may be separately used as a unit, or two or more units may be integrated into one unit; the above-mentioned integrated units may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0067] A person of ordinary skill in the art can understand that: all or part of the steps of implementing the above method embodiment can be completed by hardware related to program instructions, and the aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it executes the steps of the above method embodiment; and the aforementioned storage medium includes: a mobile storage device, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and other media that can store program codes.

[0068] Alternatively, if the above-mentioned integrated unit of the present invention is implemented in the form of a software function module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the embodiment of the present invention can be essentially or partly reflected in the form of a software product that contributes to the prior art. The computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as mobile storage devices, ROM, RAM, magnetic disks or optical disks.

Claims

1. A method for synchronous planning of general arc command position and posture transition of a robot arm, characterized in that: The following steps are involved: Determine the center and radius of the circle based on user data, wherein the user data includes a start point, an end point, and a spatial reference point; A target arc is obtained based on the spatial reference point combined with the center of the circle, and the target arc is proportionally divided to obtain different arc lengths; Determine the synchronization conditions, specifically including obtaining the set transition segment parameters and multiplying them by different arc lengths to obtain the transition start point and transition end point; The curve speed is planned according to the total arc length, and the position and attitude values ​​are determined according to the interpolation points, and the joint control commands of the robot arm are generated based on the position and attitude values.

2. A method for synchronously planning the position and posture transition of a general arc command of a robot arm according to claim 1, characterized in that: The determining of the center and radius of the circle based on user data, wherein the user data includes a starting point, an end point, and a spatial reference point, specifically includes: Get spatial reference points P1, P2 and P3; Determine the plane and the plane normal vector based on the spatial reference points P1, P2 and P3; After the plane is determined, the center of the circle is obtained by combining equidistance constraints and plane constraints, and the radius is calculated simultaneously.

3. A method for synchronously planning the position and posture transition of a general arc command of a robot arm according to claim 2, characterized in that: The step of obtaining a target arc based on the spatial reference point combined with the center of the circle and dividing the target arc proportionally to obtain different arc lengths specifically includes: Calculate the attitude difference of spatial reference points P1, P2 and P3 to obtain the synchronous planning value; The target arc obtained by the spatial reference points P1, P2 and P3 and the center of the circle is divided into different arc lengths based on different positions, wherein the segment between the spatial reference points P1 and P2 is arcL1, and the segment between the spatial reference points P2 and P3 is arcL2.

4. A method for synchronously planning the position and posture transition of a general arc command of a robot arm according to claim 3, characterized in that: Determining the synchronization condition specifically includes obtaining the set transition segment parameters and multiplying them by different arc lengths to obtain the transition start point and the transition end point, specifically including: Get the blend-ratio parameter of the transition segment, which is a value in the interval [0,1] and the maximum length does not exceed half of the shortest arc length of the two arc lengths; The different arc lengths are multiplied by the transition segment parameter blend-ratio to obtain arc length positions corresponding to the transition start point and the transition end point.

5. A method for synchronously planning the position and posture transition of a general arc command of a robot arm according to claim 4, characterized in that: The curve speed is planned according to the total arc length, and the position and attitude values ​​are determined according to the interpolation points. The joint control commands of the robot arm are generated based on the position and attitude values, which specifically include: Performing S-curve velocity planning according to the total arc length to determine a displacement function and a velocity function; Determine the interpolation point corresponding to the total arc length of the arc based on the displacement function and the speed function; Based on the interpolation points, position and posture synchronous proportional mapping movement is performed to obtain the position and posture values ​​for interpolation movement, wherein the position and posture values ​​are specifically decomposed into different joint control commands corresponding to the current robot arm to control the movement of the robot arm.

6. A method for synchronously planning the position and posture transition of a general arc command of a robot arm according to claim 5, characterized in that: The method further includes: in the process of interpolation point motion, connecting two transition segments of arc length by a fifth-order polynomial, wherein the fifth-order polynomial is as follows: x(t)= a_0 + a_1 t + a_2 t^2 + a_3 t^3 + a_4 t^4 + a_5 t^5; Where x(t) is the displacement at time t; a_0, a_1, a_2, a_3, a_4, a_5 are the coefficients of the polynomial, and t is time.

7. A robot arm universal arc command position and posture transition synchronization planning system, characterized in that: The invention comprises a memory and a processor, wherein the memory comprises a method program for synchronously planning a general circular arc instruction position and a posture transition of a robot arm, and when the method program for synchronously planning a general circular arc instruction position and a posture transition of a robot arm is executed by the processor, the following steps are implemented: Determine the center and radius of the circle based on user data, wherein the user data includes a start point, an end point, and a spatial reference point; A target arc is obtained based on the spatial reference point combined with the center of the circle, and the target arc is proportionally divided to obtain different arc lengths; Determine the synchronization conditions, specifically including obtaining the set transition segment parameters and multiplying them by different arc lengths to obtain the transition start point and transition end point; The curve speed is planned according to the total arc length, and the position and attitude values ​​are determined according to the interpolation points, and the joint control commands of the robot arm are generated based on the position and attitude values.

8. A robot arm general arc command position and posture transition synchronization planning system according to claim 7, characterized in that: The determining of the center and radius of the circle based on user data, wherein the user data includes a starting point, an end point, and a spatial reference point, specifically includes: Get spatial reference points P1, P2 and P3; Determine the plane and the plane normal vector based on the spatial reference points P1, P2 and P3; After the plane is determined, the center of the circle is obtained by combining equidistance constraints and plane constraints, and the radius is calculated simultaneously.

9. A robot arm general arc command position and posture transition synchronization planning system according to claim 8, characterized in that: The step of obtaining a target arc based on the spatial reference point combined with the center of the circle and dividing the target arc proportionally to obtain different arc lengths specifically includes: Calculate the attitude difference of spatial reference points P1, P2 and P3 to obtain the synchronous planning value; The target arc obtained by the spatial reference points P1, P2 and P3 and the center of the circle is divided into different arc lengths based on different positions, wherein the segment between the spatial reference points P1 and P2 is arcL1, and the segment between the spatial reference points P2 and P3 is arcL2.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a method program for synchronously planning the position and posture transition of a general circular arc instruction for a robot arm. When the method program for synchronously planning the position and posture transition of a general circular arc instruction for a robot arm is executed by a processor, the steps of a method for synchronously planning the position and posture transition of a general circular arc instruction for a robot arm as described in any one of claims 1 to 6 are implemented.

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