Synchronous control of linear servo systems for CNC machine tools

This paper presents a synchronous control scheme for a high-speed machine tool using linear servomotors. The gantry machine tool is mainly composed of three linear servomotors: one for the X-axis and the other two as a parallel pair for the Y-axis. The advantage of such a structure with two parallel linear servomotors for a single axis is to enable the machine to operate at high speed and acceleration and to increase the stiffness and precision. However, the major concern is the precisely synchronous movement of the pair of linear servomotors, and to overcome this problem, a master/slave control technique is applied. Repetitive control for periodic errors compensation is also considered here. Experimental results are presented to demonstrate the effectiveness of the proposed control systems.