Model-based fault detection and control design – applied to a pneumatic industrial application

In safety critical applications it is important to detect faults that may compromise system safety and to take appropriate action. This paper discusses research carried-out on the development and validation of a model-based fault detection and isolation (FDI) system for a pneumatically actuated Stewart platform. The FDI scheme is based on combining parity equation and Kalman filter based techniques. The parity and Kalman filter equations are formulated and used to generate residuals that, in turn, are analysed to determine whether faults are present in the system. Details of the design process are given and the experimental results are compared. The results demonstrate that both approaches when combined can successfully detect and isolate and in some cases accommodate faults associated with the sensors, actuators (servo-valves and piping) and the pneumatic system itself.