A discrete-time multiple-model MRAC scheme for adaptive actuator failure compensation

A new discrete-time actuator failure compensation control scheme is developed, using a multiple-model adaptive control approach which has the capacity to achieve faster and more accurate compensation of failure uncertainties. An individual adaptive system, for each possible failure pattern in a failure pattern set of interest for compensation, is designed using an indirect model reference adaptive control (MRAC) scheme for actuator failure compensation. A multiple-model control switching mechanism for discrete-time systems is set up by finding the minimal performance index to select the most appropriate control law. The performance index is based on the adaptive estimation errors of individual parametrized systems with actuator failures. Simulation results from an aircraft flight control system example are presented to show the desired closed-loop system stability and tracking performance despite the presence of uncertain actuator failures.