Design of MIMO integral variable structure controllers

The MIMO integral variable structure control (MIMOIVSC) scheme is proposed for a class of linear MIMO dynamic systems with nonlinear matched perturbat ions. This scheme is composed of two types of controllers. One is variable structure controller, which gives robust stability for system in the presen ce of parameter variations, uncertainties, and/or disturbances. The other i s integral controller, which can eliminate steady-state error for step trac king. When the system is in the sliding mode, the dynamic equations of the closed-loop system can be reduced to a linear form and its eigenvalues can be arbitrarily assigned. In addition, an observer can be employed for state estimation, so that the state variables need not be measured. The fulfillm ent of sliding condition, including the case when estimated states are used , is verified. Two numerical examples are given to demonstrate the applicab ility of the proposed control scheme, (C) 1999 The Franklin Institute. Publ ished by Elsevier Science Ltd. All rights reserved.