ROBUST STABILIZATION OF MIMO NONLINEAR TIME-VARYING MISMATCHED UNCERTAIN SYSTEMS

This paper considers the problem of robust stabilization of multi-inpu t-multi-output (MIMO) nonlinear systems in the presence of mismatched time-varying uncertainties. Combining the differential geometric feedb ack linearization with the deterministic approach, it derives two robu st stabilizing controllers, i.e. the high-gain feedback controller and the variable structure controller. These two controllers only require the knowledge of the nominal system and the bounds of the uncertainti es. Therefore, they are more feasible to be implemented. Both controll ers reduce the effects of arbitrarily large bounded mismatched uncerta inties successfully to achieve uniform ultimate boundedness stabilizat ion of the MIMO nonlinear time-varying uncertain systems. (C) 1997 Els evier Science Ltd.