Variable Structure Control Based On Sliding Mode Prediction For Inverted Pendulum Systems

Sliding mode variable structure control (SMVSC) which is an important branch ofnonlinear control theory, has attracted more and more attention because of its perfectfeatures of arbitrary robustness and complete adaptation to matching uncertainties andexternal disturbances. In recent years, in order to overcome the shortcoming ofSMVSC and apply it into more actual productions, SMVSC is conbined with othercontrol theories by many researchers. Variable structure control (VSC) based onsliding mode prediction uses receding horizon optimization and feedback correctionto optimize the reaching process of sliding mode for the purpose of chatteringelimination and enhancing robustness. Some problems of VSC based on sliding modeprediction are studied in this thesis, and the main contents of it are outlined asfollows,ⅰ) A new discrete reaching law is presented in order to deal with the flaw whichexits in conventional variable structure reaching law method. The convergence ofnew reaching law for nominal and uncertain systems is proved. Good performanceand robustness of this reaching law is showed by simulations.ⅱ) The method of sliding mode prediction controller designed and the guidelinefor tuning parameters is introduced. The module of sliding mode prediction isonstructed to achieve the real-time simulation. Finally, the result of comparisonwith conventional variable control showes that the method of sliding modeprediction has smaller steady-state error and good robustness when the uncertaintyand external disturbance of systems are strong.ⅲ) Sliding mode prediction controller is used for the research of balancing andself-erecting control of single pendulum. The experiment results are illustrated theinfluence of the predictive domain and the good performance of sliding modeprediction.ⅳ) Based on the foregoing chapters, the method of sliding mode prediction issuccessfully used to the double pendulum. The experiment has confirmed thismethod possesses robustness to the higher order nonlinear system and laid thefoundation for more complexed pendulum.The last chapter summarizes the thesis and gives perspective.