Sensor and actuator fault detection and isolation for a high performance aircraft engine bleed air temperature control system

In this paper, an unscented Kalman filter (UKF) based method is developed to detect and isolate both sensor and actuator faults and applied to a high performance aircraft bleed air temperature control system. Known UKF based fault detection and isolation methods deal with sensor faults or actuator faults only. For the aircraft bleed air temperature control system studied in this paper, potential faults associated with both the temperature sensor and valve actuators of the control system need to be considered. The proposed method contains two unscented Kalman filters: one is used to detect sensor fault and the other is dedicated to actuator fault. Nonlinear state space equations describing the engine bleed air temperature control system dynamics are derived and utilized in the design and analysis of the proposed fault detection and isolation method. Computer simulations and experiments have been conducted, and the proposed fault detection method is shown to be effective in detecting and isolating sensor and actuator faults.