Adaptive Disturbance Accommodating Control using Kalman Filter Estimator

The disturbance accommodating control theory provides a method for designing feedback controllers which automatically detect and minimize the effect of waveform-structured disturbances. This paper presents a disturbance accommodating controller which utilizes a Kalman estimator to determine the necessary corrections to the nominal control input and thus minimizes the adverse effects of model uncertainties and external disturbances on the controlled system. The control technique presented here is based on the idea that all the external disturbance and model uncertainties can be lumped into a disturbanceterm. A deterministic Lyapunov stability analysis conducted on the controlled system reveals a lower bound requirement on the estimator parameter to ensure the stability of the closed-loop system when the nominal control action on the true plant is unstable. Validity of the stability analysis is verified by implementing the proposed technique on a two degree-of-freedom helicopter.