Hierarchical FTSMC of a Class of Under-actuated Systems

Analysis of the control and decision method for the asymptotic stability of a class of under-actuated nonlinear systems with disturbances is presented.Based on fast terminal sliding mode control(FTSMC),a hierarchical control——hierarchical fast terminal sliding mode control(HFTSMC)——is proposed,which divides the system into subsystems according to the coupling of state variables and implements fast terminal sliding mode control respectively.Lyapunov method is adopted for designing the controller.A new decision method of the asymptotic stability of all sliding planes is proposed,and two approaches for designing the 2nd sliding surface are given.Matlab simulations and experiments of a rotary inverted pendulum system show the validity and effectiveness of the proposed controller and the decision method.