A discrete multi-estimation adaptive control scheme for stabilizing non-inversely stable continuous-time plants using fractional holds

This paper presents a discrete-time adaptive control strategy for stabilizing potentially non-inversely stable, continuous-time, linear and unstable time- invariant plants. Such a strategy is based on a set of discretized plant models and a supervisor which activates online one of them, which parameterizes an adaptive controller for matching asymptotically a stable discrete-time reference model. The active model is maintained in operation at least a minimum residence time for stability purposes. This multiple model adaptive control scheme improves the behavior of the system in the inter-sample times with respect to a single model adaptive control scheme.