Nonlinear High Precision Control Of Servo Turntable

Servo turntable is an important device which has been used in numerous fields. It is a basic component of CNC machining center, industrial robot, radar equipment, etc. The performance of the servo turntable directly affects the overall performance of this device. Therefore, the research on the high precision control of the servo turntable is an important direction in the field of automation.This thesis first analyzes the development and application of the servo turntable, and design the single axis servo turntable experimental system. The servo turntable is built in the open source design method, a industrial computer is used as the control core, and high performance servo driver and AC servo motor are selected as actuator. Using VS 2010 developed a set of servo control software. On the basis of the above, a nonlinear NP-ID control law is proposed and applied to the servo turntable. The tracking accuracy of the proposed algorithm is greatly improved compared to the linear PID control law. However, the closed loop stability of the servo turntable can not be guaranteed by this NP-ID law. To get ride of the above problem, a sliding mode control method is proposed, and the global asymptotic stability of the control system is proved by using Lyapunov direct method. The experimental results show that the proposed algorithm can improve the tracking accuracy.Considering the introduction of switching function in sliding mode control may lead to high frequency chattering, and the method of eliminating this chattering by using saturation function in practical operation can not guarantee asymptotic stability of the system, a adaptive control law is designed to solve the problem. The experimental results on the servo turntable experimental setup show it can further improve the tracking accuracy of the servo turntable.