The Error Compensation Strategy of 3-TPT Parallel Machine Tool Based on Semi-Closed Loop Control

This paper took a kind of 3-TPT Parallel Machine Tool (PMT) as the object of research; it mainly introduced the process of establishing the compensation strategy for this PMT. Firstly the kinematics equation of this PMT was established on the basis of kinematics analysis, the results showed that the kinematics equation of this PMT have characteristics that are simple calculation, explicit expression and unique solution. Then according to the structural characteristics and the results of kinematics analysis, the error compensation strategy of feedback correction type with the semi-closed loop control mode was used in the error compensation for this PMT by the method of assembling the gratings on the driving rods, namely the compensation way of “parallel driving and parallel feedback” was adopted. The research results in this paper provided a theoretical basis for realizing error compensation of this PMT, and had important practical significance for improving machining precision of PMT.