The Design And Simulation Of AC Servo Control System On NC Machine

Servo system drived by PMSM is the middle connect segment between numerical control setting and machine tools. This paper researches on the AC servo system of numerically controlled machine tools. The PID controller model of current circle, speed circle and position circle in the AC servo system are established. The PID parameter optimization theory and fuzzy adaptive control theory are applied for optimization the PID parameters. The result of simulated by MATLAB/SIMULINK has indicated that the efficiency and accuracy can be evidently improved and dynamic characteristic can be greatly reformed.This thesis first introduces the mathematic model of PMSM. Then the operation principle of PMSM and the basic theory of Vector Control for PMSM are all illuminated. The control model of PMSM and current circle, speed circle and position circle in the AC servo system of numerically controlled machine tools are established. Based on these, PID parameters of multi-closed loop system is adjusted according to the control theory. The result of simulated has indicated that the whole model is correct. Then we adopt an optimal algorithm for PID tuning based on the synthesize performance and analyze the results of the three optimization-rules. The simulation results indicated that the IGISE rule is the most adaptable to optimize the PID parameters of the AC servo system of PMSM. The novel method offers the new platform for the optimization of the servo system. Then the feeding model of NC machine tools is analyzed. Being aimed at the requirement of high precision of NC machine tools, we construct the modern analyse method utilizing computer aided designing and simulation. It describes T-domain characteristics and S-domain characteristics more precisely and conveniently. It describes the influence of multi-parameters change. At last, being directed against nonlinear and random control objects such as NC machine tools, a fuzzy controller with self-tuning parameter was implemented in the AC servo system of numerically controlled machine tools in this paper. This controller is capable of automatically adjusting the three parameter of PID controller according to the tracking error e and the change in error ec. The robustness can be improved greatly in AC servo control system and the following error can be reduced substantially.These novel methods can provide thought and technique for the design and test of servo control system .