Improvement of the Generalized Force Criterion Optimization of Overhead Cranes Movement Modes

Abstract

During the operation of overhead cranes, pendulum oscillations of the payload are often observed, which causes uneven movement of these cranes, their trolleys, loads on the ropes and power elements of the cranes, which, in turn, create various inconveniences during their operation, reduce the reliability of the functioning of both the crane as a whole and its individual elements. It is clear that all of these factors must be taken into account in the refined calculations of cranes (especially in the modes of their optimal (with the minimum driving force required for this) start/braking). The paper uses a standard methodology and scheme for calculating pendulum oscillations of a payload on the cables of an overhead crane, which are usually carried out within a two-mass model of a crane system. Further refinements and improvements to the above methodology have been made on the basis of a well-founded generalized force criterion for the quality of crane movement. The dependencies describing the law of motion of the crane system and the law of change in time of the applied driving force during the startup/braking stages were obtained, which satisfy the above-mentioned power criterion and ensure high-quality (smooth) movement of the system during its startup or braking. The law of motion of the crane rotation mechanism (crane drive) at its stopping, as well as the law of motion of the cargo at its lifting by the corresponding crane mechanism and sharp braking, at which the dynamic loads in the drive and in the crane rope, respectively, are minimized, is established. The results obtained in the work can be further used to clarify and improve the existing engineering methods for calculating the start-up modes of overhead cranes both at the stages of their design and in the modes of real operation.