Estimation/decoupling approach for robust Takagi–Sugeno UIO-based fault reconstruction in nonlinear systems affected by a simultaneous time-varying actuator and sensor faults

ABSTRACT

This paper presents a robust design of Takagi–Sugeno Multiple-Integral Unknown Input Observer (TSMIUIO) for nonlinear systems affected by a simultaneous time-varying actuator and sensor faults, sensor noise and unknown input by using novel estimation/decoupling approach. In comparison to the available literature, the motivation for this approach is to: (1) attain robust fault reconstruction against the effects of bi-directional interaction accompanying the use of extended state observer (ESO) to simultaneously estimate actuator and sensor faults. (2) Guarantee accurate fault reconstruction despite the time behaviour of the fault. (3) Reduce the order of the TSMIUIO by avoiding the use of ESO for estimating all faults. The ${\mathcal{L}}_2$-norm minimisation has been exploited to ensure robust global stability against system disturbances. The design algorithm has been formulated using linear matrix inequality framework. Finally, the effectiveness of the proposal is illustrated by using a single-link flexible joint robot.

KEYWORDS:

• Robust fault estimation
• robust observer design
• T–S fuzzy model
• nonlinear observer
• unknown input observer

Additional information

Notes on contributors

Ali Saad Hadi

Ali Saad Hadi was born in Baghdad in 1994. He received a BSc degree in electronic engineering and MSc degree in electronic and communication engineering from the University of Technology, Baghdad, Iraq, in 2016 and 2018, respectively. His research interests include robust fault estimation, fault detection and diagnosis, robust observer design, nonlinear observer, fault tolerant control, estimation and compensation, wind turbine and renewable energy systems.

Montadher Sami Shaker

Montadher Sami Shaker was born in Baghdad in 1979. He graduated at the Electrical Engineering Department, University of Technology-Iraq (EEDUOT) with BSc and MSc degrees in Electronic and Communication Engineering in 2001 and 2005, respectively. He completed his PhD in Electrical Engineering in 2012 at the School of Engineering, University of Hull, UK. He is a member of the academic staff at the EEDUOT since 2005. Currently, he is Assistant Professor at the EEDUOT with research interest in fault tolerant control, model-based fault diagnosis methods, sliding mode control, and control of renewable energy systems.

Qusay A. Jawad

Qusay A. Jawad received his BSc in 1993, MSc in 1998, and PhD in 2008 from the University of Technology-Iraq. He is Assistant Professor at the Energy and Renewable Energy Research Center with research interest in power, thermal energy, and heat transfer.