Abstract
This paper takes the motion units of the series-parallel machine tool (SPMT) as the basic research objects. Combined with the meta-action theory, the FMA-MBS structure model is proposed to describe the spatial structure relationships and motion transfer relationships of SPMT. Based on the simplified model, the kinematics characteristics of the machine tool are gradually researched from four layers: joint layer, limb layer, subsystem layer, and the whole machine. According to the twist system of limbs and moving platform, the parallel motion system can be simplified into a virtual motion chain with specific constraints. Then, the kinematics model of SPMT is constructed in twist exponential form. By introducing two virtual degrees of freedom (DOFs), the unified expressions of active and passive joint errors are obtained. All motion systems error models are derived based on three basic error terms of the meta-action layer. Based on the error mapping relationships, the precision of the machine tool can be calculated and evaluated. In order to illustrate the applicability and effectiveness of the proposed method, a sample library of common SPMTs and a case study of a 5-axis series-parallel machining center are provided.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
