.6-the Thrt Parallel Robot Calibration

In order to improve the accuracy of the 6-THRT parallel manipulator, kinematic calibration is needed. In this paper, Using the D-H (Denavit-Hartenberg) establish the ideal and actual kinematic model. A method of pose measurement is present by a additional central measure-axle. It is used to directly measure the position and orientations of the parallel manipulator. Making an Analysis about source of errors and the characteristic of the measurement mechanism. The explicit formulation of the 6-THRT parallel manipulator is given by the measurement model. Establishing a goal function through reverse kinematic model. Using the iterative least squares algorithm to identify the actual structural parameter of the parallel manipulator. The results of computer simulation for kinematic calibration of the parallel robot shown that the measurement precision of the measurement mechanism is better ,and that the actual structural parameter of the parallel manipulator can be fast and efficiently identified by the method of calibration.