Study of Precision Calibration of 3TPS Type Parallel Robot

Abstract

Structural parameters error due to the manufacture and installation of the robot components affect the positioning accuracy and precision of the agency. The approach of kinematic calibration will be used to assure the accuracy of the 3TPS parallel manipulators in the paper. Error model of kinematics calibration base on kinematics equation is set up to identify sources of error, and the point coordinates of tool nose are measured by the SGC- 4.2 grating ruler etc. The nonlinear error equation is solved to identify the error parameter by using the Least Square Method, and the error will be compensated. Calibration results are verified with precision, standard deviation, root mean square error, maximum error. The kinematic calibration experiment is performed on the prototype of a 3-TPS-PT machine tool. Experiment results show that the kinematic calibration method can lead to a better accuracy of the manipulator. The study of this paper is meaningful in kinematic calibration of other parallel manipulators.