Fault diagnosis and fault-tolerant control for system with fast time-varying delay

Xiao-Ye Xi,Jian-Fei Zhao,Ting-Zhang Liu,Li-Min Yan

doi:10.1080/00051144.2019.1639122

Xiao-Ye Xi, Jian-Fei Zhao + Show 2 more

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https://doi.org/10.1080/00051144.2019.1639122

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Journal: Automatika	Publication Date: Jul 28, 2019
Citations: 8	License type: open-access

Affiliation: Shanghai University

Abstract

This paper proposes a fault diagnosis and fault-tolerant control method for a system with a fast time-varying delay and time-varying parameters. A fault observer is designed to estimate faults, and an improved fast adaptive fault estimation (FAFE) algorithm is developed to reduce the relevant constraints in the general form of this algorithm. With newly introduced relaxation matrices, this study estimates faults in a system exhibiting a fast time-varying delay. Based on the estimated faults, an output feedback controller is designed to accommodate the faults. The fault-tolerant control is realized using the introduced relaxation matrices. An algorithm is derived to solve for the observer and controller. Finally, the theory and method are validated using a real example of a helicopter system.

Highlights

With the increasing complexity of control systems in modern industrial processes and the increasing requirements of reliable systems [1,2], the diagnosis and accommodation of faults for dynamic systems have become more important.The diagnosis and accommodation of faults for systems with a time delay is an important and challenging task [3,4,5] because many realistic systems exhibit a time delay [6]
The method is unsuitable for systems with a fast time-varying delay [12]
In the fast adaptive fault estimation (FAFE) algorithm, the corresponding constraints need to be calculated via an approximate method

Summary

Introduction

With the increasing complexity of control systems in modern industrial processes and the increasing requirements of reliable systems [1,2], the diagnosis and accommodation of faults for dynamic systems have become more important.The diagnosis and accommodation of faults for systems with a time delay is an important and challenging task [3,4,5] because many realistic systems exhibit a time delay [6]. A sliding mode observer has been designed to estimate faults; in this method, the system demand is so high that its applicability is poor [9]. It is only suitable for systems with a constant or a slow time-varying delay. An adaptive observer was designed to estimate faults in a system with a time-varying delay using the common adaptive fault estimation (CAFE) algorithm. This method is simple and effective while being less restrictive on the system and faults. No method has been provided for fault-tolerant control of the system [13]

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Conclusion