Vibration Control of an Overhead Crane by the Elimination Method of the Natural Frequency Component

(Path Planning for the Trolley in the Horizontal Plane)

Abstract

An overhead crane is widely used at factories, and it plays an important role in the mass transportation system. The main trouble in operation of the overhead crane is that the residual vibration of a cargo often occurs at the end of motion. In addition, the development of the automatic operation system is desired for an efficient and safe transportation. In this 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 contain any component 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 trajectory of the trolley of the overhead crane which enables complete prevention of the residual vibration of the cargo. Also, in order to reduce the rapid velocity change of the trolley and large swinging of the cargo during transportation, the authors optimized the trajectory of the trolley by using the method of Lagrange multiplier. This paper deals with a 2-dimensional overhead crane and design routing path for obstacle avoidance, then applies the vibration control method. The results show that the trolley moves along the path planned in advance, preventing the residual vibration.