Research On Stabilization And Disturbance Estimation Control Of A Benchmark System

Underactuated systems,which have less available control inputs than degrees of freedom,are widely used in various fields,because underactated systems have advantages of simple structure,low energy consumption,high flexibility,and so on.Translational Oscillator with Rotation Oscillator(TORA)is one of the typical underactuated benchmark systems,which is used to investigate and examine nonlinear control problem.Therefore,studying the control problems of TORA system has important theoretical and practical significance.This thesis studies the stabilization control problem of the 2DTORA system and disturbance estimation control of the TORA system mainly.Compared with the TORA system,the two-dimensional TORA system(2DTORA)has more complex dynamic characteristics,and the controller design of 2DTORA system is more difficult.In practice,the angle of the 2DTORA system may exist the unwinding behavior,which means that the ?(t)= 0 and ?(t)= 2n? represent the same angle in the same physical space.But most of existing control methods can't distinguish the two angle.To solve this problem,this thesis will propose a output-feedback controller,and considers the physical actuator may has the maximum value and the velocity signal is not measurable in the meanwhile.Finally,the simulation in MATLAB are provided to illustrate that the proposed controller can achieve the expected control performanceIn the practical control systems,disturbances is general.For the TORA system in existence of disturbances,this thesis studies the disturbances estimation problem of this system by using the sliding mode control method and the disturbance observer.In order to reduce the chatting of the traditional sliding control method,this thesis propose a disturbance observer.Then,it is well known that the robustness to disturbances and parameter uncertainties of the traditional sliding control method only exists in the sliding phase.Therefore,on basis of the disturbance observer,a global sliding mode controller is proposed in this thesis,which is eliminating the reaching phase and has global robustness.Finally,by using MATLAB,the simulation tests show that the proposed controller not only has effective control performance,but also can reduce the chattering.