Designing a Fault Detection and Isolation Unit for a Helicopter System

Helicopters are complex systems consisting several interdependent elements. Any faults in such complex systems may lead to physical damage and loss of life. Therefore, it is essential to design a mechanism for timely detection and isolation of faults, prior to any further action. In this study, a Fault Detection and Isolation (FDI) unit based on state observers’ theory is suggested in order to deal with electronic faults in the main and tail actuator circuits. Our suggested unit utilizes N + 1 observers, where one observer is used for fault detection and the rest for isolation. A fault is isolated when the residue signal corresponding to its observer does not exceed its threshold level, whilst at least one of the residue signals corresponding to other observers does. Furthermore, residue signals in the suggested unit are designed adaptively to eliminate modeling uncertainties in FDI process. For simulation, a helicopter model with 6 DOF (Degree Of Freedom) is considered which occupies parametric uncertainties. Simulation results indicate system’s ability to detect and isolate faults

Keywords:

Helicopter , Fault Detection and Isolation , Adaptive Threshold , State Observer