Title: Root cause analysis of actuator fault based on invertibility of interconnected system

Authors: Mei Zhang; Ze-tao Li; Michel Cabassud; Boutaïeb Dahhou

Addresses: Electrical Engineering School, Guizhou University, 550025, Guiyang, China; CNRS, Laboratoire de Génie Chimique, F-31030 Toulouse, France; UPS, Laboratoire de Génie Chimique, Univ de Toulouse, F-31030 Toulouse, France ' Electrical Engineering School, Guizhou University, 550025, Guiyang, China ' CNRS, Laboratoire de Génie Chimique, F-31030 Toulouse, France; UPS, Laboratoire de Génie Chimique, Univ de Toulouse, F-31030 Toulouse, France ' CNRS, LAAS, F-31400 Toulouse, France; UPS, LAAS, Univ de Toulouse, F-31400 Toulouse, France

Abstract: This paper addresses the problem of root cause analysis (RCA) of actuator fault. By considering an actuator as an individual dynamic subsystem connected with process dynamic subsystem in cascade, an interconnected system is then constituted. The fault detection and diagnosis (FDD) algorithm is carried out in actuator subsystem and aims at identifying the root causes of actuator faults. According to real plant, outputs of the actuator subsystem are assumed inaccessible and are reconstructed by measurements of the global system, thus providing a means of monitoring and diagnosis of the plant at both local and global level. A condition of invertibility of the interconnected system is first developed to guarantee that faults occurring in the actuator subsystem will affect the measured output of the global system distinguishably. For that, a necessary and sufficient condition is proposed to ensure invertibility of the interconnected system. Effectiveness of the proposed approach is demonstrated on an intensified HEX reactor.

Keywords: root cause analysis; RCA; interconnected system; invertibility; fault detection and diagnosis; FDD; actuator FDD; input reconstruction; left invertibility; control valve; actuator subsystem; process subsystem; adaptive observer.

DOI: 10.1504/IJMIC.2017.084723

International Journal of Modelling, Identification and Control, 2017 Vol.27 No.4, pp.256 - 270

Received: 16 Dec 2015
Accepted: 09 Jun 2016
Published online: 22 Jun 2017 *

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