Study of the Direct Drive Feed System with Fuzzy Reasoning Self-adjusting Control

High speed cutting has been used in manufacturing industry more and more extensively. For a high-speed cutting CNC machine tool, the high velocity feed system is a must. The direct drive feed system by linear motors is an ideal solution to realize the high-speed feed. But in this system, the cutting force and load mass of the moving parts are directly imposed on the system and are direct disturbance. The variation of the moving mass and cutting force may affect the control system to be unstable and to reduce the system´s positioning accuracy. In this paper, a new control method with off-line fuzzy reasoning and on-line self-adjusting is introduced into this system to improve the dynamic performance of the system. Firstly, a fuzzy controller is designed to self-adjust the direct drive system´s control parameter. Based on the real time requirements of the system, the fuzzy controller is realized by an off-line enquiry table. Secondly, the calculation process of the off-line enquiry table is described in detail. Thirdly, the simulation analysis with MATLAB on a practical system with this fuzzy controller is realized. The simulation results show this method can improve the stability and dynamic performance of direct drive feed system distinctly