Global Sliding Mode Variable Structure Control And Its Application Research For Inverted Pendulum Control

Inverted pendulum is an unstable, multi-variable, nonlinear and strong-coupling system, so a valid control method must be used to keep it stable.Global sliding mode variable structure control inherits a series of advantages ofsliding mode variable structure control, and has whole robustness onuncertainty of parameter and disturbance outside. So that the research onapplying it to inverted pendulum control is made.In the thesis, based on dynamics analysis on single inverted pendulumsystem, mathematical model is established, which is also the basic of controllerdesign. Using global sliding mode variable structure control theory, severalkinds of global sliding mode variable structure controller were designed. Firstly,one kind of global sliding mode variable structure controller is based on usualdiscrete reaching law and choosing suitable global sliding mode factor to buildswitch function. The approach guarantees that the trajectory of the system fromdiscretional initial state arrives at the sliding surface at the very beginning.Secondly, aiming to the problem of discrete reaching law, improved discretereaching law is offered. And based on the new theory, one kind of globalsliding mode variable structure controller was designed. Thirdly, according tothe characteristics of global sliding mode variable structure, one kind of globalsliding mode variable structure controller is designed by adopting equivalentcontrol method. This controller has simple form and easy to be realized. It canalso solve the problem of system vibration on previous controller, which wasdesigned based on discrete reaching law method. At last, aiming at invertedpendulum controlled object with uncertainty, one kind of global sliding modevariable structure controller is designed. Regarding to uncertainty of parameterand unknown disturbance outside, another kind of controller is designed byapplying delay characteristic to estimate this uncertainty on-line and usingequivalent control method. This method can overcome the limit on previouscontrol method, which must be based on known uncertainty and meet matchingconditions. Both theory analysis and simulation on inverted pendulum canprove the validity of these methods.