Active Disturbance Rejection Approach for Robust Fault-Tolerant Control via Observer Assisted Sliding Mode Control

Hebertt Sira-Ramírez,Alberto Luviano-Juárez,Horacio Coral-Enriquez,Harvey Rojas-Cubides,John Cortés-Romero

doi:10.1155/2013/609523

Abstract

This work proposes an active disturbance rejection approach for the establishment of a sliding mode control strategy in fault-tolerant operations. The core of the proposed active disturbance rejection assistance is a Generalized Proportional Integral (GPI) observer which is in charge of the active estimation of lumped nonlinear endogenous and exogenous disturbance inputs related to the creation of local sliding regimes with limited control authority. Possibilities are explored for the GPI observer assisted sliding mode control in fault-tolerant schemes. Convincing improvements are presented with respect to classical sliding mode control strategies. As a collateral advantage, the observer-based control architecture offers the possibility of chattering reduction given that a significant part of the control signal is of the continuous type. The case study considers a classical DC motor control affected by actuator faults, parametric failures, and perturbations. Experimental results and comparisons with other established sliding mode controller design methodologies, which validate the proposed approach, are provided.

Highlights

The main challenge of the Fault-Tolerant Control is to guarantee high performance and reliability in the most adverse operations such as the presence of perturbations, disturbances, dynamic miss-modeling, and actuator faults among others
In this work we propose an approach of passive faulttolerant control based on a classic sliding mode controller assisted by a Generalized Proportional Integral (GPI) observer under the context of the active disturbance rejection
We describe the experiments that were carried out to assess the performance of the proposed GPI observer assisted sliding mode control (SMC+GPIobs) against the classic sliding mode control (SMC) applied to a mechatronic system affected by perturbations and faults

Summary

Introduction

The main challenge of the Fault-Tolerant Control is to guarantee high performance and reliability in the most adverse operations such as the presence of perturbations, disturbances, dynamic miss-modeling, and actuator faults among others. Passive techniques exploit the robustness of some types of controllers without requiring changes in their structure and can operate satisfactorily without information about system failures. These techniques are usually simple in implementation but are not usually suitable for severe cases of failures [1]. The robust characteristics of the sliding mode technique provide a natural environment for the use of such techniques on passive FTC schemes This technique has been properly used in different control schemes and assisted by other effective control strategies which have shown proper performance under fault-tolerant operations (see [1,2,3,4] as representative examples). Considerable attention has been paid to the design of linear/nonlinear disturbance observers for sliding mode controller assistance in order to overcome several issues like chattering [5,6,7,8], disturbances and system uncertainties [8,9,10], coupling of MIMO systems [11], or uncertainties, disturbances, and actuator faults [12]

Methods

Results

Conclusion