Controlling motion of metal bascule structures by fluid power system (exemplified by lifting of bascule bridge span)

Abstract

This article discusses the dynamics of power processes upon motion of bascule metal structures peculiar for many lifting heavy-duty mechanisms. Due to the forces of inertia, during the acceleration of the mechanism with a load, fluctuations in power parameters occur: efforts; stress; pressures that can lead to the destruction of the metal structures of machines. Due to high alternating load oscillations, the working capacity of machinery decreases about 3 times, herewith, this problem is traced for machinery in various industries. Using the motion of large-tonnage span of bascule bridge as the example, at the design stage it is proposed to apply simulation modeling in order to determine optimum law of drive control, in particular: the law of variation of flow rate in fluid power systems. The article presents the results of simulation of hydraulic lifting mechanisms of a single-wing bascule bridge. Two basic algorithms of proportional control are considered: by the form of the function in the form of a trapezoid and by the form of the cosine function. The results indicate the possibility of significantly reducing the amplitude of fluctuations in load parameters during acceleration of mechanisms and, thereby, to increase the service life of heavy machines. To achieve such results, it is recommended to change the existing algorithms for automatic control of the speed of the mechanisms of heavy machines. Despite the fact that this issue has been studied quite well in cybernetics, it still remains relevant in applied technical specialties, in the design of modern heavy machines. In project organizations, along with constructive design methods, digital, computational design methods should be actively developed.