Precision motion control for the parallel mechanism of a virtual axis machine tool

The precision motion control problem of a virtual axis machine tool is addressed in this paper, which is still one of the biggest obstacles of commercialization of the virtual axis machine tool. Firstly, the kinematics analysis of the parallel mechanism of a 6-DOF virtual axis machine tool is made. Secondly, a joint-space trajectory planning based on the cycloid movement is conducted to ensure the stability of the mechanism movement. Finally, according to the characteristics of the parallel mechanism of the virtual axis machine tool, a novel completely chattering-free sliding mode control system is designed to achieve the high-precision control of the virtual axis machine tool. The simulation results show that the control system has a good performance in tracking and anti-interference and can achieve the accurate control of the branches of the virtual axis machine tool. Furthermore, it is not necessary to establish the accurate mathematical model of the parallel mechanism of the virtual axis machine tool and easy to design and implement.