An advanced position control of overhead crane by sway suppression method emulating natural damping

Overhead crane is widely used to convey the payload due to its convenience. However it is hard to control the crane because of its underactuated structure. The most important control requirement is to make the trolley position converge to target position accurately with suppressing payload sway. This makes it possible to achieve the purpose of overhead crane which is to convey payload to target position stably. In the practical implementation, however, the achievement of both conveying trolley to target position and suppressing payload sway is not always easy. In this paper, emulating natural damping method is proposed. The natural damping is defined as energy damping of crane system caused by trolley friction. Not only trolley but also payload energy is damped by natural damping effect. The proposed approach brings to achieve both trolley position convergence and payload sway suppression.