Maturation and in-flight testing of H fault detection and accommodation for a model-scale autonomous aircraft

This paper describes the maturation and in-flight testing of a recently developed fault detection (FD) system for a model scale unmanned aerial vehicle (UAV). The FD system design methodology is based on H techniques and exploits an LFT description of the aircraft (A/C) longitudinal dynamics. The maturation of the FD system, presented in the paper, introduces a fault isolation logic to distinguish between bias and stuck-in-place faults in the elevator, and a fault accommodation strategy to recover the nominal operation of the controller, thus attaining fault detection and isolation (FDI) and fault tolerant control (FTC). An overview of the experimental setup of the FDI/FTC system is described, presenting the high-fidelity Functional Engineering Simulator (FES) development environment, the UAV platform, and the flight test plan definition. Results are presented for the FDI/FTC system tested in real-time and onboard the UAV, for typical maneuvers of climbing/descent, turning, cruising and waypoint following, covering the expected flight envelope. Extension of the system for a planetary exploration glider is also briefly discussed.