Cost-detectability and Stability of Adaptive Control Systems

Hysteresis switching adaptive control systems designed using certain types of L2e-gain type cost functions are shown to be robustly stabilizing if and only if certain plant-independent conditions are satisfied by the candidate controllers. These properties ensure closed-loop stability for the switched multi-controller adaptive control (MCAC) system whenever stabilization is feasible. The result is a safe adaptive control system that has the property that closing the adaptive loop can never induce instability provided only that at least one of the candidate controllers is capable of stabilizing the plant.