Detection and accommodation of sensor faults in UAVs- a comparison of NN and EKF based approaches

In this paper we propose two schemes for sensor fault detection and accommodation (SFDA); one based on a neural network (NN) and the other an extended Kalman filter (EKF). The objective is to compare both approaches in terms of execution time, robustness to poorly modelled dynamics and sensitivity to different fault types. The schemes are tested on an unmanned air vehicle (UAV) application where traditional sensor redundancy methods can be too heavy and/or costly. In an attempt to reduce the false alarm rates and the number of undetected faults, a modified residual generator, originally proposed in [11], is implemented. Simulation work is presented for use on a UAV demonstrator under construction with support from BAE Systems and EPSRC. Results have shown that the NN-SFDA scheme outperforms the EKF-SFDA scheme with only 1 missed fault, zero false alarms and an average estimation error of 0.31deg/s for 112 different test conditions.