Vibration Control of Overhead Traveling Crane by the Eliminating Method of the Component of Natural Frequency

(Optimization of Trolley Orbit)

Abstract

An overhead traveling crane is widely used at ports and factories, and it plays an important role in the mass transportation system. The main trouble in operation of the overhead traveling crane is that the residual vibration of a cargo often occurs at the end of motion. At present, the prevention of the residual vibration has to depend on the proficient skills of operators. Therefore, the automatic operation system of the overhead traveling crane is strongly desired for an efficient and safe transportation. In our former research, a new type of open-loop control method has been proposed for suppressing the residual vibration. This method is based on the dynamical property that the residual vibration does not occur in a linear undamped system when it is excited by an external force which does not involve the components of natural frequencies of the system. The authors have applied this property to a nonlinear damped system and developed an efficient method to derive an adequate orbit of the trolley of the overhead traveling crane which enables complete prevention of the residual vibration of the cargo. However, there is a problem that fast motion of the trolley results in large swing motion of the cargo. This paper proposes an optimization method to design the motion of the trolley which minimizes the angular displacement of the cargo during transportation.