Fault-tolerant control for the multi-quadrotors cooperative transportation under suspension failures

Abstract

This paper focuses on the fault-tolerant control of the multi-quadrotors cooperative payload transportation under suspension failures. A dynamic load reassignment and control strategy is proposed for the cooperative quadrotors by incorporating the high-order sliding mode disturbance observer into a dynamic surface control-based backstepping design. The dynamics of the cable-suspended payload transportation with multiple quadrotors are formulated. The unmeasurable suspension cable tensions, which will greatly impact the quadrotors' dynamics and stability, are respectively viewed as one part of the lumped disturbance and estimated by the super-twisting sliding mode-based finite-time disturbance observers. With the estimated disturbance compensation, the dynamic surface control laws are established for the cooperative quadrotors. Moreover, to guarantee the fault-tolerant control under suspension cable broken, a dynamic load assignment strategy is proposed to stably recover the cooperative load transportation. Finally, the stability of tethered quadrotors' flight control systems is analyzed. The simulation results show the effectiveness of the proposed algorithm under suspension failures.