Uniting Two Output-Feedback Controllers with Different Objectives

The problem of robustly, globally stabilizing a point (or set) with two nonlinear output-feedback hybrid controllers is considered. These control laws may have different objectives, e.g., both closed-loop systems may have different attractors. We provide a control algorithm that combines the two hybrid controllers to accomplish the task. It consists of a hybrid supervisor that, based on the values of plant's outputs and state estimates, selects the hybrid controller that should be applied to the plant. The accomplishment of the stabilization task relies on an output-to-state stability property induced by the controllers, which enables us to construct an estimator for the norm of the plant's state.