Stekhno O. Mode-parametric optimization of the derricking mechanism of a tower crane

The analysis of existing researches on the topic of the dissertation work was carried out. It was found that little attention was paid to the study of dynamic loads in the components of the derricking mechanism. In addition, the problems that allow minimizing energy losses in the asynchronous electric motor of the mechanism based on the optimal tuning of its frequency-controlled drive have been insufficiently studied. Besides, insufficient attention is paid to the problems of optimal control of the movement of the mechanism, which make it possible to take into account the effect on the cargo of additional stochastic loads, as well as to combine the desired characteristics of several modes of optimal control in a complex manner. A significant number of analyzed works were performed for the parameters of the mechanisms of a crane. In order to prove the adequacy of the theoretical results obtained in the work, all calculations were carried out for the parameters of the derricking mechanism, corresponding to KБ-674, 200 EC-H 10 Liebherr, MTD 128 Potain and 5 LC 5010 5t Linden Comansa cranes. To study the dynamics of the load of the traction rope of derricking mechanism, a three-mass dynamic model was developed. The angular coordinate of the drive rotation and the trolley and load linear coordinates of the motion of the centers of mass were taken as generalized coordinates. Improvements of the components of the derricking mechanism were developed. They make it possible to minimize the amount of undesirable dynamic loads during its operation. The constructive solutions were proposed for the modernization of the trolley and its wheels, rope drum, as well as a method of optimal control of the dynamic system "trolley-load", with the robustness to the wind gusts. An algorithm was developed for the implementation of optimal control of the derricking mechanism according to the optimal parameters of the frequency-controlled drive of the derricking mechanism and according to the laws of its movement. The economic efficiency of the mode-parametric optimization of the derricking mechanism for four tower cranes was determined. The economic effect from minimizing energy losses is from 273.7 to 423.9 UAH/year, and from reducing the duration of the cycle of movement of a trolley with a load on a flexible suspension is from 23588.3 to 109497.1 UAH/year in 2021 prices.