IJCAS

In this work, a robust adaptive anti-swing control strategy is proposed for the quadrotor slung-load system (QSLS) with constrained flight states and unknown disturbances. Based on the online trajectory planning approach, the smooth reference trajectory is generated. Different from the traditional extended state observer method, a novel compensation function observer is developed to handle the unknown disturbances, which has better observation accuracy. Meanwhile, by means of the barrier Lyapunov function (BLF) technique, the boundary of the state errors can be guaranteed within the specified range. Especially, the presented method can solve the singularity problem that the denominator of the BLF reaches zero at some point. Following the design flow of backstepping methodology, an adaptive tracking control scheme is developed for the QSLS such that the swing angles are stable with time and the constrained flight states are not violated invariably. Finally, contrastive simulation results validate the validity of the proposed control algorithm.

Keywords: Compensation function observer, quadrotor slung-load system, state constraints, tracking control, trajectory planning.