关键词: 并联机构, 位姿误差, 奇异值分解法

Abstract: To evaluate the motion accuracy of machine tool, a method for determining the actual pose of rigid body based on Singular Value Decomposition(SVD) method was proposed. The moving platform of 3RPS parallel machine was considered as a rigid body in space, by measuring the coordinate value of multi-points (5~10) in moving platform with laser tracker, the actual pose of the moving platform was obtained by SVD method. The moving platform pose errors were detected in practice by comparing real pose to the corresponding theoretical one. The sum of squares of body points position errors obtained after pose transformation was used as objective function for analyzing the measurements, and bad point was rejected according to the objective function value, so that the effect of bad points on the result was removed. The proposed method avoided bad result which was calculated just from three points because of bad point. Practical examples verified the rationality and feasibility of SVD method, which was applicable to the study of pose errors detection of a rigid body in space.

Key words: parallel mechanism, pose error, singular value decomposition method, measurements, machine tools