Robust Disturbance Rejection Based Control with Extended-state Resonant Observer for Sway Reduction in Uncertain Tower-cranes

In this paper, the problem of load transportation and robust mitigation of payload oscillations in uncertain tower-cranes is addressed. This problem is tackled through a control scheme based on the philosophy of active-disturbance-rejection. Here, a general disturbance model built with two dominant components: polynomial and harmonic, is stated. Then, a disturbance observer is formulated through state-vector augmentation of the tower-crane model. Thus, better performance of estimations for system states and disturbances is achieved. The control law is then formulated to actively reject the disturbances but also to accommodate the closed-loop system dynamics even under system uncertainty. The proposed control schema is validated via experimentation using a small-scale tower-crane,and compared with other relevant active disturbance rejection control(ADRC)-based techniques. The experimental results show that the proposed control scheme is robust under parametric uncertainty of the system, and provides improved attenuation of payload oscillations even under system uncertainty.

Data-driven disturbance observer-based control: an active disturbance rejection approach

In this paper,a data-driven method for disturbance estimation and rejection is presented.The proposed approach is divided into two stages:an inner stabilization loop,to set the desired reference model,together with an outer loop for disturbance estimation and compensation.Inspired by the active disturbance rejection control framework,the exogenous and endogenous disturbances are lumped into a lotal disturbance signal.This signal is estimaed using an on-line algorithm based on a data-driven predictor scheme,whose parameters are chosen Io salisfy high robustnessperformance criteria.The above process is presented as a novel enhancement lo design a disturbance observer,w hich constitutes the main contribution of the paper.In addition,the control strategy is completely presented in discrete time,avoiding the use of discretization methods for its digital implementation.As a case study,the voltage control of a DC-DC synchronous buck converter aflected by disturbances in the input voltage and the load is considered.Finally,experimental results that validate the proposed stralegy and some comparisons with the classical disturbance observer-based control are presented.