Adaptive output feedback actuator nonlinearity compensation for multivariable systems

This paper develops a framework of adaptive compensation of actuator nonlinearities with unknown parameters, for output feedback control of unknown multi-input multi-output linear time-invariant dynamic systems. A new controller parametrization is derived to deal with bilinear parameters from the actuator nonlinearity parameters and the dynamic system parameters, which, based on the LDU decomposition of the system high frequency gain matrix, is capable of overcoming the difficulty caused by a nondiagonal high frequency gain matrix and a special actuator nonlinearity parameter structure. The adaptive actuator nonlinearity compensation control scheme is a model reference adaptive control based design, employing an adaptive output feedback control law combined with an adaptive actuator nonlinearity inverse, to deal with parameter uncertainties in the system dynamics and actuator nonlinearities. Simulation results show the desired adaptive control system performance.