Passive and active nonlinear fault-tolerant control of a quadrotor unmanned aerial vehicle based on the sliding mode control technique

In this paper, an augmented sliding mode-based fault-tolerant control is designed theoretically, implemented practically and tested experimentally in a quadrotor unmanned aerial vehicle testbed under propeller damage and actuator fault conditions for tracking control. In view of the significant feature of robustness inherent to the sliding mode control technique, the developed sliding mode-based fault-tolerant control strategies have been designed and implemented in the two currently and widely used types of fault-tolerant control strategy, i.e. passive and active, with the intention to investigate and compare the advantages, disadvantages and application considerations and limitations of these two different fault-tolerant control strategies in the tracking control problem of a quadrotor unmanned aerial vehicle application. Therefore, these two types of controller have been carried out in both theory and practice with and without the presence of faults. Both theoretical and experimental analyses demonstrated the effectiveness of the two sliding mode-based fault-tolerant control strategies in the application to the quadrotor unmanned aerial vehicle under a small level of actuator faults or damage. Detailed comparisons are also provided in the paper to demonstrate the capabilities, advantages and disadvantages of the two types of fault-tolerant tracking controller under different flight conditions in the presence of actuator faults and propeller damage.