| With the development of advanced technology and science, the performance requirements of the servo system also increased dramatically, the nonlinear friction is one of the most important factors to affect the performance of the servo system, especially when the speed is low, it’s esaily to cause waveform distortion phenomena and creeping phenomenon.The topics of this thesis is designed adaptive robust control of servo system for nonlinear friction based on the LuGre model of friction. As a theoretical foundation, the friction characteristics and models is detailed analyzed. Based on this, used the LuGre model of friction to created the dynamics model of servo system.The traditional PID control and the Sliding Mode Control were designed for the servo system based on the LuGre model of friction, and researched the theoretical analysis and the simulation, the result of simulation shows that the PID control of the low-speed performance is poor,and the Sliding Mode Control has chattering.In order to overcome the parameter uncertainties, external disturbances and unmodeled dynamics in actual servo system, the Adaptive Robust Controll was designed. which contains the Adaptive Controll, the linear feedback part and the Deterministic Robust Control. the Adaptive Controll has a high tracking accuracy, but poor robustness; the Deterministic Robust Control has a strong robustness, but there is a larger steady state error. On this basis, the Adaptive Robust Rontrol was designed, theoretical analysis shows that it can effectively overcome the friction nonlinear system uncertainties and external disturbances, the tracking error within the required range, the simulation results also verify the validity of the method. Further consider the impact of measurement noise on the system, the Desired Compensation Adaptive Robust Control was designed, it can effectively inhibited the influence of measure-ment noise, and its effectiveness is verified by simulation. |
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