An Adaptive Filter-Based Equivalent-Input-Disturbance Approach for Networked Control Systems With Measurement Noise

This article addresses the disturbance rejection problem for networked control systems subject to time-varying delays and measurement noise. First, the uncertainty caused by the delay is modeled to be a delay-induced disturbance and treated as part of the lumped disturbance. Second, an adaptive-filter-based EID estimator is proposed to estimate this lumped disturbance under the effect of measurement noise. A new filter is designed by introducing an adjustable zero. Then, an adaptive characteristics-adjustment mechanism is constructed for the filter to resolve the contradiction between fast disturbance reconstruction and measurement noise attenuation. Finally, experimental results reveal the superiority of the proposed method.