A disturbance decoupled adaptive observer and its application to faulty parameters estimation of a hydraulic driven elevator

In this paper, a robust adaptive observer for joint state-parameter estimations has been designed for systems with unknown disturbances. By integrating the unknown input observer (UIO), a disturbance decoupled estimation of both states and parameters is achieved. An auxiliary input is added to the UIO in coping with the estimation errors so that the exponential stability and convergence are guaranteed. The proposed observer is applied to the faulty parameter estimation of a hydraulic driven elevator. The simulation results show the accuracy of the observer and its robustness to both disturbances and measurement noises.