Unmanned AerialVehicles (UAV) has historically shown to be unreliable when
compared to their manned counterparts. Part of the reason is they may not be
able to a ord the redundancies required to handle faults from system or cost
constraints. This research explores instances when actuator fault handling may
be improved with integrated approaches for small UAVs which have limited
actuator redundancy.
The research started with examining the possibility of handling the case where
no actuator redundancy remains post fault. Two fault recovery schemes, combing
control allocation and hardware means, for a Quad Rotor UAV with no redundancy
upon fault event are developed to enable safe emergency landing.
Inspired by the integrated approach, a proposed integrated actuator control
scheme is developed, and shown to reduce the magnitude of the error dynamics
when input saturation faults occur. Geometrical insights to the proposed actuator
scheme are obtained. Simulations using an Aerosonde UAV model with the
proposed scheme showed significant improvements to the fault tolerant stuck
fault range and improved guidance tracking performance.
While much research literature has previously been focused on the controller
to handle actuator faults, fault tolerant guidance schemes may also be utilized to
accommodate the fault. One possible advantage of using fault tolerant guidance
is that it may consider the fault degradation e ects on the overall mission.
A fault tolerant guidance reconfiguration method is developed for a path following
mission. The method provides an additional degree of freedom in design,
which allows more flexibility to the designer to meet mission requirements.
This research has provided fresh insights into the handling UAV extremal
actuator faults through integrated approaches. The impact of this work is to expand
on the possibilities a practitioner may have for improving the fault handling
capabilities of a UAV
