Adaptive actuator failure compensation using multiple-model switching

A new adaptive actuator failure compensation control scheme is developed, using a multi-layer multiple-model and switching approach, for effective and faster compensation of failure uncertainties, and improvement of system transient performance. A basic-layer multiple-model adaptive compensation control structure is first developed to ensure effective failure compensation, by using a set of basic multiple adaptive controllers, each designed for one failure pattern from a failure pattern set. Then, a multi-layer multiple-model adaptive control scheme is employed to improve system transient performance, using multiple groups of adaptive controllers. Each group is designed by expanding each basic controller structure to a set of subgroups of controllers, with controllers from different subgroups initialized from different parameter subregions, and controllers within each subgroup updated by different adaptation gains. A control switching mechanism is designed based on cost functions formed from tracking error related estimation errors, and selects the applied control input from the multiple control signals, which corresponds to the minimal cost function. Simulation results from an aircraft flight control example are presented to show the desired system performance despite the presence of uncertain actuator failures.