Adaptive output feedback control for MIMO plants with unknown orders

This paper deals with the design problem of adaptive stabilizing controllers for MIMO plants with unknown orders. A design scheme for an output feedback based adaptive control system, which has hierarchical structures derived from backstepping strategies, is proposed for MIMO plants with unknown orders but with known relative MacMillan degrees (relative degrees for SISO plants). It is also shown that all the signals in the resulting control system are bounded, and the output of the plant converges to zero asymptotically.