Load-swing suppression control using an omnidirectionally movable multi-rotor in 2D-horizontal plane

In this paper, a method for controlling the swing of loads is proposed by applying forces to a suspended load directly, instead of controlling a suspending machine itself, such as a helicopter and a crane. A special multi-rotor capable of moving in the level surface is developed to control the swing of loads. First, to create a model for controlling the swing of loads, a drone model is used to model a multi-rotor that can generate forces in ( x , y )-directions and also produce a torque for yaw-rotation, and has four special coaxial rotors, while a double spherical pendulum is used as a rope model which hangs the multi-rotor. Moreover, in what is called a control allocation problem that determines the number of revolutions of each rotor, assume that the number of revolutions for each rotor consists of one for generating two forces in translational motion, and of one for generating one torque in rotational motion. Then, the number of revolutions for plane movement is first decided at the 1st step, and the number of revolutions for a torque required for yaw motion is next decided from the difference between the torque generated by the translational forces decided at the 1st step and the target torque. Finally, the validity of the proposed load-swing suppression control is verified with simulations.