关键词: 并联机构, 误差模型, 姿态约束, 运动学标定

Abstract: To improve the kinematic accuracy of a 6-PSS parallel mechanism, its error analysis and calibration were researched. The error model of 6-DOF parallel mechanism was established by vector method, and the sensitivity of structure parameters to the pose error of the moving platform was obtained by MATLAB tool. Through comprehensive analysis for mechanism's error, on the basis of this mechanism, a new kinematic calibration method based on pose constraints of mechanism coordinate-axis was proposed combining with the forward and inverse of kinematics. According to initial measurement value, the calibration values of mechanism were obtained by using calibration algorithm. The displacement and angle error before calibration and after calibration were obtained with external measuring equipment, and the displacement error was improved from 10 mm to 1 mm and angular error was improved from 0.3°to 0.1°after calibration. The experimental results showed that the proposed calibration method was valid and effective, and could improve the kinematic accuracy of parallel mechanism.

Key words: parallel mechanism, error models, orientation constraint