Robust Online Control Allocation-Based FTC With Aircraft-in-the-Loop Validation

This article proposes a holistic actuator fault tolerant control (FTC) scheme and validates it using the Japan Aerospace Exploration Agency's Multi-Purpose Aviation Laboratory (MuPAL-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\alpha$</tex-math></inline-formula>) Aircraft-in-the-Loop platform. The motivation for this work is to increase the technology readiness level associated with FTC technology, whilst improving the sustainability of future aircraft. The overall scheme uses bespoke sliding mode observers at a (local) individual actuator level to assess the health and the effectiveness level of each of the actuators. These estimates are aggregated and used in the control allocation mechanism to distribute a virtual control signal, designed using sliding mode control concepts, to the physical actuators. The overall closed-loop system stability is rigorously analyzed. The validation results show that the actuator effectiveness is well reconstructed and near nominal lateral-directional control performance is retained in the face of a class of actuator faults.