Global improved integral fuzzy sliding mode control of a class of underactuated system

In order to keep a class of underactuated uncertain system's good robustness and dynamic performance against system uncertainties and external disturbances,aglobal improved integral fuzzy sliding mode control(SMC)method is proposed.Improved integral SMC method reduces the integral term by adjusting factor outside the boundary layer and softens the control input,which reduces the conventional SMC's inherent steady-state error and prevents integral SMC's integrator windup.On this basis,aglobal integral slide mode is designed to make the system lie on the sliding-mode at the initial stage and achieve the full robustness of the system.In order to solve the problem that factor adjustment must be continuously tested to obtain satisfactory dynamic performance,a fuzzy interface system is designed to reduce the complexity of the process.Finally,the steady-state performance of this method is analyzed.Theoretical analysis and simulation results prove that the method is effective.