A Fault-Tolerant Control Scheme for Fixed-Wing UAVs with Flight Envelope Awareness

In this work a vertically integrated fault-tolerant control scheme for fixed-wing Unmanned Aerial Vehicles (UAVs) is presented. At its core, an online approximate Trim Flight Envelope generator yields the motion constraints of the UAV. Given fault information, it remains always up-to-date in view of emerging faults. The controller stack comprises of Nonlinear Model Predictive Controllers for angular velocity, linear velocity and position. Path Planning is achieved by Simple Sparse Rapidly-exploring Random Trees (SST). Both the controllers and the planner are aware of the flight constraints and are hence tolerant to faults. A large set of sensor and actuator faults, common to UAVs are considered and the controllability of the UAV is examined. Detailed simulations using real-time implementations of the controllers are carried out.