Minimisation of the driving torque of the derricking mechanism of a tower crane during steady load hoisting

Abstract

Efficient use of a tower crane often requires combining various operations, such as hoisting load and derricking. In the case when the load is hoisted at a steady speed, the problem of optimal control of the trolley movement mechanism arises, which goes beyond engineering calculations and is a scientific and applied problem. Its relevance is related to improving the controllability of crane mechanisms, increasing the capacity and reliability of the crane, and improving the energy efficiency of its drive mechanisms. These indicators are related to the choice of optimisation criteria. Thus, the purpose of the study is to optimise the starting mode of the derricking mechanism according to the criterion of the RMS value of the driving moment during a steady load hoisting. To achieve this goal, the following methods were applied: dynamics of machines and mechanisms, mathematical modelling, integral and differential calculus, and the ME-D-PSO method. For the boundary conditions, parameters are selected that eliminate load oscillations on the flexible suspension when the derricking mechanism slews to the steady-state driving mode. Based on the results of optimisation of the joint movement of mechanisms for derricking and load hoisting, graphical dependences of kinematic, dynamic, and energy characteristics of the start-up transition process are constructed and their analysis is carried out. The obtained dependences reveal the conditions for eliminating load oscillations on a flexible suspension during steady-state movement and reducing dynamic loads and energy losses during the start-up of the derricking mechanism. To implement the optimal start mode of the derricking mechanism during steady load hoisting, it is recommended to use optimal control of the drive mechanisms. The results obtained should be applied to the development of new and modernisation of existing motion control systems for tower crane mechanisms

Optimization of manipulator's motion mode on elastic base according to the criteria of the minimum central square value of drive torque

“…This article presents an approach to optimization by the function of torque similar to that considered in [19] for the mechanism of rotation of the tower crane. Note that in the mechanism of rotation of the crane at the beginning of the movement, there is no significant external load, in contrast to the mechanism of lifting the boom, and therefore to compensate for such a moment at the beginning of the movement is not required.…”