Research On Control System Of Servo Turntable For Optical Communication

With the rapid development of astronautics and aeronautics technologies,the demand of servo turntable for optical communication is increasing.In this thesis,based on a type of servo turntable for optical communication,the control system and the friction compensation technique are studied to guarantee that the turntable can track target with high accuracy.The research result shows that friction interference can be suppressed for improving the dynamic tracking performance,which is of great academic and application value.Firstly,based on the Kinematics and Dynamics,the mathematical model of turntable is established with taking consideration of the influence of friction torque and saturation nonlinearity,and also,the Stribeck model is used to approximate the system friction torque.According to the technical index requirements and characteristics of servo turntable,the main components of the control system are selected.And the fiction parameters are also determined by the utilization of the Stribeck friction model.All these works lay the foundation for the main research results.Secondly,the whole scheme of servo turntable control system is designed and the switching control scheme is designed for tackling the instability problem of the precise position system at the large deviation input.In the aspect of hardware,the hardware circuits such as the DSP minimum system,the SCI communication module,A/D and D/A conversion module and the EPLD module are introduced in detail.In software,the controllers of the turntable in different working modes are designed based on the classical control theory and the performance requirements;then,the corresponding digital controllers are obtained based on the bilinear transform theory.Furthermore,the control system timing interrupt program module,SCI communication module and other function modules are programmed and debugged on the CCS software platform.At last,the system coordination and performance testing are carried out.Finally,in view of the large friction moment interference of the turntable system,a method of friction compensation based on model reference fuzzyadaptiveness is proposed.Based on the mathematical model of the azimuth axis of the turntable,the friction compensation method is simulated and verified.The simulation results show that the friction compensation method can effectively suppress the adverse effect of friction interference and improve the low speed servo accuracy of the turntable azimuth axis.