Design and implementation of command and friction feedforward control for CNC motion controllers

Motion controllers play a pivotal role in the development of high-performance CNC machines. Precision motion control is achieved with a control structure employing S-curve motion planning on the velocity command before interpolation, command feedforward and friction feedforward compensation. To evaluate the performance of the proposed control scheme, a servomechanism is controlled to track a circular curve in the form of nonuniform rational B-splines, where the desired motion information such as velocity and acceleration are also provided. Experimental results indicate that the proposed motion-control structure exhibits a better performance, when compared with conventional motion-control schemes.