Adaptive Compensation of Actuator Failures using Multiple Models

Abstract

In this paper, a novel actuator failure compensation scheme is proposed for affine nonlinear uncertain systems subject to actuator faults/failures unknown in time, magnitude and pattern. The proposed control methodology utilizes a backstepping procedure integrated with multiple estimation models to estimate failure induced parametric uncertainties and unknown system parameters. Relative to existing direct adaptive backstepping based fault compensation strategies, the proposed fault tolerant control (FTC) method yields a faithful accommodation of uncertain actuator failures while ensuring satisfactory output transient and steady state performances. Further, compared to multiple model based adaptive FTC design, the proposed methodology circumvents the issues of stability due to switching between different models and utilizes a minimum number of estimation models for parameter estimation without sacrificing the output performance and thereby reducing the computational burden. Simulation results illustrate the effectiveness and applicability of the proposed method to FTC design problem for longitudinal pitch control of Boeing 747-100/200 aircraft.