Research On The Application Of Intelligent PID Control Algorithm In Economical Closed Loop NC System

At present, economical computer numerical control machine tools are mostly Open Loop NC system. The Closed Loop NC machine tools have many problems such as low manufacturing precision, low real-time performance. Thus, this paper proposes an open architecture Closed Loop NC system based on the IPC+DSP Motion Controlling Card.This paper discusses the developing history of NC system and its status, the character of economical NC system and its developing trends. Based on this, we choose the IPC+DSP controlling structure. The basic theory of Fuzzy PID control, the principle of Fuzzy PID control and the structure and the design of Fuzzy PID control are introduced. Then the feeding model of NC machine tools is analyzed. Based on this, Fuzzy PID controller + Pre-feed controller is designed and is simulated with MATLAB. Analysis in detail of the control effect shows that Fuzzy PID controller is appropriate to nonlinear control objects such as NC machine tools. System hardware structure introduces hardware research & development,and straight line,arches interpolation and velocity controlling are discussed as well. The software design includes the data structure of data transportation, the DSP main program, the Fuzzy PID program and the drive program of the Motion Controlling Card etc.