Research On Servo Control Performance And Dynamic Characteristics For Machine Tool

CNC technology is widely used in mechanical manufacturing industry at present. The stability and responsiveness of machine tool in processing are very important. Due to these reasons, the dynamic characteristic of machine tool is required to study. The dynamic analysis of machine tool is mainly to study the capacity which against the dynamic force. The better performance of machine tool against vibration makes the machine tool work better. Servo feed system affects not only the stability of machine tool, but also the response of machine tool. Efficient and stable servo feed system can improve machine process ability. The aim of this thesis is to study the stability and the response of servo system in processing. The following aspects are studied in this thesis:(1)Composition unit of the servo system are analyzed, the mathematical model of servo drives part and mechanical transmission are established. A complete servo feed system mathematical model is established;(2)The mathematical model of the servo system is simplified. The influence of Servo system characteristics on the machining accuracy is analyzed. According to the result, the dynamic characteristics of machine tool are analyzed;(3) Some parameters of the servo system which are from the bench of self-made three-axis NC machining tool are calculated. The parameters are designed to parameterization. Then the parameters are calculated to adapt different machine tools and servomotors. SIMULINK is used to establish model and simulation.(4)Methods of PID controller optimizing are compared. The PID parameters are optimized by using genetic algorithm. The actual process is done on a self-made three-axis NC machine tool and simulation curve of two different PID controller parameters are compared to evaluate the optimization results.The right servo system model is gained. The PID controller parameters of servo system are optimized by using genetic algorithm. On one side, the cutting surface is compared to show the difference of the effect of optimizing. On the other side, simulation curve of two different PID controller parameters are compared. The result shows that PID parameters optimizing can make the servo system work better.