Dynamic Output Feedback Variable Structure Control for System Stabilization

The use of the so-called simplex type dynamic output feedback variable structure control for stabilizing a class of multivariable linear time-invariant plants is analyzed. Two types of controllers are considered; a compensator type and an observer type. It is shown that while the compensator type controller stabilizes the plant only if the plant is minimum-phase, the observer type controller does not face the same restriction. In addition, the design of low-order observer type controllers is considered.