Positioning Error Analysis And Compensation Under The Constraint Condition Of The S-R-S Seven-Dof Serial Robot

With the widespread application of serial robots in industrialization,industrial robots and rehabilitation robots are becoming more and more popular.The pose accuracy of the end effector is an important indicator to measure the performance of robots.How to improve the accuracy of the end pose has attracted wide attention.Due to various error,the actual end pose and the theoretical end pose of the serial robot have certain error.These error seriously affect the application of the serial robot in high precision applications.This paper will mainly study the influence of structural parameters on the end positioning accuracy,aiming at improving the end precision,and performing positioning error analysis and compensation under the constraint conditions.The main work of the thesis is as follows:(1)D-H kinematic modeling,forward and inverse kinematic analysis and simulation verification,and computational verification of Jacobian matrix are firstly carried out for the S-R-S serial robot.(2)Aiming at the problem that the kinematic parameters of the robot have less influence on the accuracy of the end pose,Sobol global sensitivity analysis is used to eliminate these parameters that have less influence on the accuracy of the end pose.According to the actual application,three different dimensionality-reduction D-H error models of end pose are established for different accuracy requirements.(3)Aiming at the problem that the task space in practical application is generally smaller than the working space of the serial robot and the excessive working space is not conducive to improving the accuracy of the end pose.This paper proposes a calibration method based on task space.(4)In this paper,a constrained model based on Cartesian space is proposed.By adding different kinds of constraint method at different joints,the robot's moving workspace is limited and the accuracy of the end effector is improved.(5)Aiming at the proposed dimensionality reduction error model,calibration method based on the task space and constrained model based on Cartesian space.In order to complete the calibration,the articulated arm three-dimensional measuring machine is used as the measuring tool,and the least square method is used to identify the parameters and compensate these error.After simulation verification,the accuracy is improved by about 87.5%.