Performance Analysis Of Industrial Robot Mechanism And Optimization Of Workpiece Setup

With the development of industry and application in the field of industrial robots,industrial robots have become an indispensable tool of modern industrial manufacturing.At the same time,the requirements with efficiency and accuracy of industrial robot machining are more demanding,so the two problems of inaccessibility and singularity of the robot manipulator are needed to be solved in the process of robot machining.In dealing with the singularity problem of robot end-effectot,the appropriate point in the neighborhood of the singular point is often used instead of the singular point,so as to avoid the singularity to complete the whole process in machining.However this will reduce the precision of machining robot.A method to optimize the position and orientation of workpiece setup is proposed.It can avoid the singularity without changing the machining trajectory,so it increases the efficiency and precision of robot machining effectively.In this paper,a study is reported on the optimal design of the position and orientation of workpiece setup with Qianjiang robot as the object of study:Firstly,according to the basic knowledge of robot kinematics,the kinematics model of industrial robot is deeply analyzed,and the forward kinematics model and the inverse kinematics model are established.The combination of joint angle value is generated through joint angle within each joint angle range of industrial robots and the robot workspace can be resolved by analytical method.Then,the values of the position of the workspace center point can be calculated by least mean square,and the trajectory bounding box is formulated according to machining trajectory.The position of workpiece setup is optimized through optimizing the center point of trajectory bounding box to the center point of workspace,in order to eliminate the inaccessibility of robot manipulator.Secondly,after the position optimization of workpiece setup,the orientation of center point of trajectory bounding box is required to be transformed if there is still singularity.The tabu search algorithm is used to optimize the orientation of workpiece setup in each quadrant directions of eight quadrant orientation in three-dimensional space,which try to meet the demand of the machining trajectory without singularity andinaccessibility to complete the orientation optimization,in order to eliminate the singularity of robot manipulator.Finally,the experimental verification on least mean square(LMS)and tabu search algorithm optimizing the position and orientation of workpiece setup is conducted in the robot off-line programming software.The test results show that there is no unreachable points and singularity under the optimized workpiece setup.The method in this paper is proved to be feasible and robust through the analysis of experimental results,and it can effectively improve the accuracy and efficiency of machining process.