Feedforward controller design and trajectory planning for point to point CNC system

Most point to point CNC systems employ traditional feedback controller such as PID controller. However, there exists the shortcoming that the transient time is too long. In order to overcome the shortcoming, we designed a feedforward controller and a motion trajectory. First, zero error characteristic of the step response of system with zero phase error tracking controller (ZPETC) is proved. Then, Based on the characteristic and the requirement of the point to point motion, the ZPETC is applied to design the feedforward controller and plan the motion trajectory. The trajectory is composed of motion and location period. So the stability, rapidity and accuracy are assured. Fig. (5) gives simulation results. They show that the control strategy and the motion trajectory are effective when the mathematical model of the plant is accurate.