Abstract
A new control system is proposed for the helicopter-slung load system near hover flight. It consists of two controllers: tracking and anti-swing. The anti-swing controller is fuzzy based and its outputs are additional displacements that are added to the helicopter trajectory in the longitudinal and lateral directions. Hence, its implementation is simple; it just needs a small modification to the software of the helicopter position controller. The rules of the anti-swing controller are derived to mimic the performance of a time-delayed feedback controller. The distribution of the fuzzy membership functions is optimally tuned using the method of particle swarms. The function of the tracking controller is to stabilize the helicopter and track the trajectory generated by the anti-swing controller. The simulation results show the effectiveness of the proposed controller in stabilizing the helicopter slung load system and suppressing the load oscillation. Moreover, the proposed fuzzy controller has better performance compared with the time-delayed feedback controller and the classical PD fuzzy controller.