Disturbance decoupled fault reconstruction using cascaded sliding mode observers

• Published in: Automatica (Oxford) Vol. 48; no. 5; pp. 794 - 799
• Main Authors: Ng, Kok Yew, Tan, Chee Pin, Oetomo, Denny
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.05.2012; Elsevier
• Subjects: Applied sciences; Computer science; control theory; systems; Control theory. Systems; Design engineering; Diagnosis; Disturbance rejection; Disturbances; Exact sciences and technology; Fault diagnosis; Fault Isolation; Faults; Feasibility; Mathematical analysis; Modelling and identification; Observers; Reconstruction; Sliding mode; Fault diagnosis; Observers; Disturbance rejection; Sliding mode; Variable structure control; Observer; Feasibility; System identification; Fault diagnostic
• ISSN: 0005-1098; 1873-2836; 1873-2836
• DOI: 10.1016/j.automatica.2012.02.005

This paper presents a disturbance decoupled fault reconstruction (DDFR) scheme using cascaded sliding mode observers (SMOs). The processed signals from a SMO are found to be the output of a fictitious system which treats the faults and disturbances as inputs; the ‘outputs’ are then fed into the next SMO. This process is repeated until the attainment of a fictitious system which satisfies the conditions that guarantee DDFR. It is found that this scheme is less restrictive and enables DDFR for a wider class of systems compared to previous work when only one or two SMOs were used. This paper also presents a systematic routine to check for the feasibility of the scheme and to calculate the required number of SMOs from the outset and also to design the DDFR scheme. A design example verifies its effectiveness.