Simulation Of Dynamic Behavior And Parameter Optimization For Servo System On CNC

The computer numerical control (CNC) system can realize the automation of production process with high precision, reliability, and efficiency. It embodies the development of technology and economy of one country. Thus the CNC system is widely studied and several key technologies, such as curve interpolation, acceleration/deceleration control, servo control and contour control have always been the research topics for the last decades. Among these technologies, servo control is especially important for high-performance CNC system. The rapidity, stability and accuracy of CNC system are highly determined by the servo system.The servo system driven by servo-motor serves as the link between the numerical control device and machine tools. In this thesis, the alternating-current (AC) servo system is studied, and mathematical models of the control system components are established. Based on that, the parameters of the control device of three closed-loop controls, namely the current-loop, speed-loop and position-loop are designed and tuned. To improve the efficiency and accuracy of the designed system, the dynamic simulations are then performed using the tool of Matlab/Simulink.In the beginning of this paper, the servo system model is found on the operational and physical principles of the servo-motor, and several main component models and transfer functions are introduced. Then the dynamic simulation models of three closed-loop controls are built, and the regulator parameters of current-loop, speed-loop are adjusted using the coordinated-control scheme method. After that, to verify the rationality of the system, the PID-regulator of position-loop is adjusted and simulated employing the genetic algorithm and improved-complex method, based on the three optimization rules of ITAE, ITSE and GISE. Simulation results show that GISE is the most appropriate rule for design. At last, the more complex double-position and double-strain control systems are built on the basis of the single-servo control system, which are simulated by the optimization algorithm for a further verification of the algorithm.