Fuzzy-PID-Based Improvement Controller for CNC Feed Servo System

The feed servo system is one of the most important mechatronics parts in CNC machine tools. However, it is very difficult to model its control system accurately because of time-varying parameters in continuous-time nonlinear system and load disturbances. This paper introduces the control methods on feed servo system aimed to promote higher precision for CNC milling machine. The main objective of our research is focus on the improvement of Fuzzy PID (FPID) controller applied to feed servo system of CNC milling machine. The performances between the developed FPID controller and conventional PID controller have been compared and evaluated on MATLAB/SIMULINK simulation. The simulation results of AC servo system with the FPID controller show that this control method not only has more robustness but also has a better adaptation capability. Furthermore, the proposed control method has been tested in the TI developed board with one horsepower Yaskawa AC servo motor. The experimental results demonstrate that the accuracy of the motion precision of CNC milling machine's axis using the proposed control system with one horsepower AC motor can achieve about 8-10 mu m.