Research And Application Of Global Robust Sliding Mode Control Theory

At present, the sliding mode variable structure control has become an importantbranch of modern control theory, and has formed a relatively complete andindependent research system.The sliding mode variable structure control has verystrong robustness and insensitivity to reject parameter perturbation and interference ofthe system of the control system;because of the advantages of less demanding on themathematical model of the system and simple design method, it has been widespreadconcern of home and abroad scholars.The movement of the sliding mode variable structure control system can bedivided into two stages, one is approach stage of the system state along a certaintrajectory reaching the switching surface, the two is the sliding mode phase of thesystem state along the switching surface moving to a stable point or equilibriumpoint.Sliding mode control has the advantages of the robustness of sliding mode phase,namely in the sliding mode phase it is not sensitive to parameter perturbation andexternal disturbance of the system.However, in the approach reaching phase of thesystem it is difficult to ensure the robustness.In addition, in the actual control system,inertial and delaying time of the system makes the sliding mode variable structurecontrol system inevitable to the emergence of the high frequency chattering.Thechattering phenomenon may affect the accuracy of the system and stimulateunmodeled high frequency of the system, thus undermining the performance of thecontrol system.This article summarizes the origin development and research status of the slidingmode control technique at home and abroad, analyzed the characteristics of slidingmode control and the shortcomings of current research.On this basis, it discusses thebasic theory and design method of global robust sliding mode control.This paperpresents three kinds designing method of the global robust sliding mode controller, inthe design of the sliding mode surface, introducing the exponential function and the integral term,combining the global robust sliding mode control with fuzzycontrol, estimating the switching gain, weakening chattering and using MATLAB tobuild a global sliding mode control system.Simulation results show that three kindsdesigning method of global robust sliding mode control obtaine successful applicationin servo control and speed control in the PMSM and DIFG no-load cutting control.