Fault Tolerant Control of Octorotor Using Sliding Mode Control Allocation
This paper presents a fault tolerant control scheme using sliding mode control allocation for an octorotor UAV. Compared to the existing literature on quadrotor or octorotor UAVs, the scheme in this paper takes full advantage of the redundant rotors to handle more than one rotor failure. A sliding mode approach is used as the core baseline controller, which is robust against uncertainty in the input channels – including faults to any of the rotors. Even when total failures occur, no reconfiguration is required to the baseline controller, and the control signals are simply re-allocated to the remaining healthy rotors using control allocation, to maintain nominal fault-free performance. To highlight the efficacy of the scheme, various types of rotor fault/failure scenarios have been tested on a nonlinear model. The results show no visible change in performance when compared to the fault-free case.