Analisys of experimental studies of optimal control of tower crane slewing and trolley movement mechanisms

Abstract

The article analyzes the quality of the implementation of the optimal laws of simultaneous motion of the tower crane slewing and the trolley movement mechanisms. The estimation was carried out according to the maximum and root-mean-square values of the deviations of the theoretical and experimental characteristics. In addition, the graphical dependencies have been built. The data were estimated according to the characteristics of the speed of movement of the trolley and the rotation of the crane, as well as the angles of deflection of the load in the normal and tangential directions in the modes of acceleration and deceleration of the mechanisms. As a result of the analysis, it was found that the main reasons for the deviation of theoretical and experimental data on the characteristics under study are that the stiffness characteristics of the crane metal structure have not been taken into account, the parameters of the mechanisms are not accurately determined, and there are no feedbacks on the control characteristics (the speed of rotation of the crane and the speed of trolley movement). However, when implementing optimal control by means of a frequencycontrolled drive, pendulum oscillations of the load in the normal and tangential planes are eliminated. In addition, the analysis of the current loads of the drives of mechanisms and the acceleration of the crane boom was carried out. It was found that with optimal control, there is a significant decrease in the maximum values of acceleration, which means a decrease in dynamic loads on the crane metal structure. Also, the maximum currents in the motor windings of the crane mechanisms have been reduced, which, of course, will have a positive effect on the energy efficiency of the crane mechanisms.