Isolation and handling of sensor faults in nonlinear systems

• Published in: Automatica (Oxford) Vol. 50; no. 4; pp. 1066 - 1074
• Main Authors: Du, Miao, Mhaskar, Prashant
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.04.2014; Elsevier
• Subjects: Adaptative systems; Applied sciences; Computer science; control theory; systems; Control theory. Systems; Design engineering; Dynamical systems; Exact sciences and technology; Fault diagnosis; Fault isolation; Fault tolerance; Fault-tolerant systems; Faults; Industrial metrology. Testing; Logic; Mechanical engineering. Machine design; Modelling and identification; Nonlinear dynamics; Nonlinear systems; Observers; Output feedback; Sensor failures; Sensors; State observers; Fault isolation; Fault diagnosis; Fault-tolerant systems; State observers; Sensor failures; Nonlinear systems; Output feedback; High gain observer; Non linear control; Feedback regulation; Fault tolerance; Chemical reactor; System identification; Incomplete information; State estimation; Measurement error; Fault tolerant system; Closed loop; Redundancy; Measurement sensor; Forming; Non linear system; Fault diagnostic; Logic model; Defect detection; Handling
• ISSN: 0005-1098; 1873-2836
• DOI: 10.1016/j.automatica.2014.02.017

This work considers the problem of sensor fault isolation and fault-tolerant control for nonlinear systems subject to input constraints. The key idea is to design fault detection residuals and fault isolation logic by exploiting model-based sensor redundancy through a state observer. To this end, a high-gain observer is first presented, for which the convergence property is rigorously established, forming the basis of the residual design. A bank of residuals are then designed using a bank of observers, with each driven by a subset of measured outputs. A fault is isolated by checking which residuals breach their thresholds according to a logic rule. After the fault is isolated, the state estimate generated using measurements from the healthy sensors is used in closed-loop to maintain nominal operation. The implementation of the fault isolation and handling framework subject to uncertainty and measurement noise is illustrated using a chemical reactor example.