Stability and performance verification before switching in new controllers using closed-loop data

Consider an interconnection of an unknown or partially known linear plant and a known linear stabilizing controller, and assume that some knowledge of the closed-loop system is available. Suppose, on the basis of that knowledge, the use of a new controller appears attractive. We provide analysis and introduce novel tests utilizing a limited amount of experimental and possibly noisy data obtained from the existing closed-loop for verifying that the introduction of a proposed new controller will not only stabilize the plant but also provide assurance for the closed-loop performance before the insertion of a new controller. The importance of this capability arises in iterative identification and control algorithms, multiple-model adaptive control, and multi-controller adaptive switching.