CN-121989259-A - Singular point avoiding method, system, equipment, medium and product of redundant mechanical arm

Abstract

The application discloses a singular point avoiding method, a system, equipment, a medium and a product of a redundant mechanical arm, which are applied to the field of redundant mechanical arm control, wherein the method comprises the steps of obtaining pose, kinematic parameters and a plurality of control constraint conditions of the redundant mechanical arm in the process of executing a main task in a robot; the method comprises the steps of determining a jacobian matrix corresponding to a redundant mechanical arm based on pose and kinematic parameters, carrying out pseudo-inverse solution on the jacobian matrix to obtain a first control quantity used for controlling execution of a main task, calculating a distance index between the pose and kinematic singular points, solving an optimization model when the distance index is smaller than a preset threshold value to obtain a second control quantity used for controlling each control constraint condition of execution of the main task, fusing the first control quantity with the second control quantity to generate an articulation control instruction, and driving the redundant mechanical arm to avoid the singular points based on the articulation control instruction. The method can improve the track precision of the redundant mechanical arm near the singular point.

Inventors

• SUN WENXING
• XU GANG
• ZHANG MIN
• Zhang Peirun
• NING XUEFENG
• WU XIAOLIANG
• LU HUAQING
• HE YUXIANG
• HE ZHONGSHAN
• LI DUANJIAO
• CHEN BIN
• LIU JIANMING
• QIN GUANGSHENG
• JIA ZIRAN
• YUE XIAO
• LIANG YONGCHAO
• Yao Juanwen

Assignees

• 广东电网有限责任公司

Dates

Publication Date

20260508

Application Date

20260408

Claims (10)

1. 1. The singular point avoiding method of the redundant mechanical arm is characterized by comprising the following steps of: Acquiring pose, kinematic parameters and a plurality of control constraint conditions of a redundant mechanical arm in the robot in the process of executing a main task; determining a jacobian matrix corresponding to the redundant mechanical arm based on the pose and the kinematic parameters, and performing pseudo-inverse solution on the jacobian matrix to obtain a first control quantity for controlling the execution of the main task; Calculating a distance index between the pose and a preset kinematic singular point, solving an optimization model to obtain a second control quantity of each control constraint condition for controlling the execution of a main task when the distance index is smaller than a preset threshold value, and fusing the first control quantity with the second control quantity to generate an articulation control instruction, wherein the optimization model is obtained by weighting each real-time priority weight and each optimization objective function, each real-time priority weight is obtained by dynamically adjusting each control constraint condition based on the distance index, and each optimization objective function is obtained by determining the optimization direction of each control constraint condition; And driving the redundant mechanical arm to avoid the singular point based on the articulation control instruction.
2. 2. The method for avoiding singular points of a redundant manipulator according to claim 1, wherein determining a jacobian matrix corresponding to the redundant manipulator based on the pose and the kinematic parameter comprises: Determining a positive kinematic model for characterizing a mapping relationship between joint space variables and end effector task space poses based on the poses and the kinematic parameters; and deriving the positive kinematic model to obtain the jacobian matrix corresponding to the redundant mechanical arm.
3. 3. The method for avoiding singular points of a redundant manipulator according to claim 1, wherein said performing pseudo-inverse solution on the jacobian matrix to obtain a first control amount for controlling execution of a primary task includes: performing pseudo-inverse operation on the jacobian matrix to obtain a corresponding jacobian pseudo-inverse matrix; determining an expected motion control amount of the main task in a task space based on a preset execution precision requirement of the main task; and carrying out mapping operation on the expected motion control quantity and the jacobian pseudo-inverse matrix to obtain a first control quantity for controlling the execution of the main task.
4. 4. The method for avoiding singular points of a redundant robot arm according to claim 1, wherein solving an optimization model when the distance index is smaller than a preset threshold value to obtain a second control amount of each control constraint condition for controlling execution of a main task, comprises: When the distance index is smaller than a preset threshold value, respectively determining a corresponding optimization objective function based on each control constraint condition; weighting each real-time priority weight and each optimization objective function to obtain the optimization model; And solving the optimization model through a gradient descent algorithm to obtain a second control quantity of each control constraint condition for controlling the execution of the main task.
5. 5. The method for avoiding singular points of a redundant robot arm according to claim 3, wherein the dynamic adjustment of each control constraint condition by each real-time priority weight based on the distance index comprises: Calculating a condition number based on the jacobian matrix and the jacobian pseudo-inverse matrix, and determining a distance index between the pose and a preset kinematic singular point based on the condition number; When the distance index is smaller than or equal to a preset first threshold value, the priority weight corresponding to the obstacle avoidance constraint condition for guaranteeing the operation safety of the redundant mechanical arm is lifted, and a first weight distribution result is determined; when the distance index is larger than a preset first threshold value and smaller than or equal to a preset second threshold value, distributing each priority weight corresponding to each control constraint condition according to a preset proportion, and determining a second weight distribution result; When the distance index is larger than a preset second threshold value, the priority weight corresponding to the energy consumption constraint condition for optimizing the operation energy consumption of the redundant mechanical arm is lifted, and a third weight distribution result is determined; And determining each real-time priority weight based on the first weight distribution result, the second weight distribution result and the third weight distribution result, wherein each control constraint condition comprises the obstacle avoidance constraint condition, the energy consumption constraint condition and the gesture constraint condition.
6. 6. The method for avoiding singular points of a redundant robot arm according to claim 1, wherein the fusing the first control amount with the second control amount to generate an articulation control instruction includes: linearly superposing the first control quantity and the second control quantity to obtain an initial joint movement control instruction; And performing joint motion constraint verification on the initial joint motion control instruction to judge whether the initial joint motion control instruction exceeds a preset joint displacement limit, and if so, performing scaling processing on the initial joint motion control instruction to obtain the joint motion control instruction.
7. 7. The singular point avoidance system of the redundant mechanical arm is characterized by comprising an acquisition module, a solving module, a control module and an avoidance module; The acquisition module is used for acquiring the pose, the kinematic parameters and a plurality of control constraint conditions of the redundant mechanical arm in the robot in the process of executing the main task; The solving module is used for determining a jacobian matrix corresponding to the redundant mechanical arm based on the pose and the kinematic parameters, and carrying out pseudo-inverse solving on the jacobian matrix to obtain a first control quantity for controlling the execution of the main task; The control module is used for calculating a distance index between the pose and a preset kinematic singular point, solving an optimization model to obtain a second control quantity of each control constraint condition for controlling the execution of a main task when the distance index is smaller than a preset threshold value, fusing the first control quantity with the second control quantity to generate an articulation control instruction, wherein the optimization model is obtained by weighting each real-time priority weight and each optimization objective function, each real-time priority weight is obtained by dynamically adjusting each control constraint condition based on the distance index, and each optimization objective function is obtained by determining the optimization direction of each control constraint condition; and the avoidance module is used for driving the redundant mechanical arm to avoid the singular point based on the joint motion control instruction.
8. 8. A terminal device comprising a processor, a memory and a computer program stored in the memory and configured to be executed by the processor, the processor implementing the singular point avoidance method of the redundant manipulator of any one of claims 1-6 when the computer program is executed.
9. 9. A computer readable storage medium comprising a stored computer program, wherein the computer program, when run, controls a device in which the computer readable storage medium is located to perform the singular point avoidance method of the redundant manipulator of any one of claims 1-6.
10. 10. A computer program product comprising a computer program or instructions which, when executed by a communication device, implements a method of singularity avoidance for a redundant manipulator according to any one of claims 1 to 6.

Description

Singular point avoiding method, system, equipment, medium and product of redundant mechanical arm Technical Field The invention relates to the field of redundant mechanical arm control, in particular to a singular point avoiding method, a system, equipment, a medium and a product of a redundant mechanical arm. Background Along with the wide application of the robot technology in the scenes of assembly, grabbing, cooperative operation and the like, the requirements on the movement flexibility and the track precision of the mechanical arm are continuously improved. The redundant mechanical arm is a mechanical arm structure with the number of joint degrees of freedom larger than the task space dimension of the end effector, and the mechanical arm still has additional degrees of freedom for adjusting the mechanical arm configuration while finishing a given main task (such as end position or gesture control), so that the mechanical arm has stronger adaptability in a complex working environment. However, since the kinematic mapping relationship of the redundant robot arm has a nonlinear characteristic, the robot arm inevitably approaches or passes through a kinematic singular point in the process of performing a high-precision trajectory tracking task. The kinematic singular point refers to a state that the Jacobian matrix of the mechanical arm is reduced in rank or pathologically changed under a specific configuration, at the moment, the mapping relation between the joint space and the task space is unstable, and the tiny joint movement can cause the obvious change of the pose of the end effector, so that the track precision is adversely affected. The existing control method for the redundant mechanical arm mostly adopts a control strategy based on Jacobian pseudo-inverse or conventional zero space decomposition, and can realize a better track tracking effect when the control strategy is far away from a singular point, but when the control strategy is close to the singular point, the control solution is highly sensitive to noise and model errors due to the fact that the Jacobian matrix condition number is increased sharply, so that track jitter, offset and even instantaneous instability of an end effector are easy to cause, and track precision is reduced remarkably. In addition, the existing method generally adopts a fixed or static zero-space control strategy, lacks a dynamic adjustment mechanism aiming at a singular region, cannot effectively coordinate the relation between the control quantity of the main task and the adjustment of the redundancy degree of freedom near a singular point, and causes that the main task track is difficult to continuously and smoothly maintain the set precision near the singular region, and is difficult to meet the requirement of high-precision operation. Disclosure of Invention The invention provides a singular point avoiding method, a system, equipment, a medium and a product of a redundant mechanical arm, which can improve the track precision of the redundant mechanical arm near the singular point. In a first aspect, an embodiment of the present invention provides a method for avoiding singular points of a redundant mechanical arm, including: Acquiring pose, kinematic parameters and a plurality of control constraint conditions of a redundant mechanical arm in the robot in the process of executing a main task; determining a jacobian matrix corresponding to the redundant mechanical arm based on the pose and the kinematic parameters, and performing pseudo-inverse solution on the jacobian matrix to obtain a first control quantity for controlling the execution of the main task; Calculating a distance index between the pose and a preset kinematic singular point, solving an optimization model to obtain a second control quantity of each control constraint condition for controlling the execution of a main task when the distance index is smaller than a preset threshold value, and fusing the first control quantity with the second control quantity to generate an articulation control instruction, wherein the optimization model is obtained by weighting each real-time priority weight and each optimization objective function, each real-time priority weight is obtained by dynamically adjusting each control constraint condition based on the distance index, and each optimization objective function is obtained by determining the optimization direction of each control constraint condition; And driving the redundant mechanical arm to avoid the singular point based on the articulation control instruction. The embodiment of the invention lays a data foundation for realizing high-precision track control nearby a singular point by simultaneously mastering the real-time motion state, the structural kinematics characteristic and various constraint requirements required to be met by task execution of the redundant mechanical arm in the control process, avoiding control deviation caused by only depending on