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Minimization of oscillations of the tower crane slewing mechanism in the steady-state mode of trolley movement

Loveikin Viatcheslav S., Romasevych Yuriy O., Korobko Mykola M., Liashko Anastasia P., Loveikin Andriy V.

Archive of Mechanical Engineering

2023

LXX, nr 3

367--385

In the present study, the problem of optimization of the motion mode of the tower crane's slewing mechanism in the steady-state mode of trolley movement is stated and solved. An optimization criterion, which includes the RMS values of the drive torque and the rate of its change over time, is minimized. The optimization is carried out taking into account the drive torque constraints, and under the specified boundary conditions of motion. Three optimization problems at different values of the weight coefficients are solved. In the first problem, priority is given to the drive torque, in the third – to the rate of the drive torque change, and in the second problem, the significance of both components is assumed equal. The optimization problems are nonlinear, thus a VСT-PSO method is applied to solve them. The obtained optimal start-up modes of the crane slewing mechanism eliminate pendulum load oscillations and high-frequency elastic oscillations of the tower. Most of the kinematic, dynamical, and power parameters at different values of the weight coefficients are quite close to each other. It indicates that the optimal modes of motion are significantly influenced by the boundary conditions, optimization parameters, and constraints

Optimization of the trolley mechanism acceleration during tower crane steady slewing

Loveikin Viatcheslav S., Romasevych Yuriy O., Loveikin Andriy V., Korobko Mykola M.

Archive of Mechanical Engineering

2022

LXIX, nr 3

411--429

The article describes optimization of the process of acceleration of the tower crane trolley movement mechanism during the steady mode of the slewing mechanism. A mathematical model of the boom system of the tower crane was used for the optimization of the trolley movement. The model was reduced to a sixth-order linear differential equation with constant coefficients, which represents the relationships between the drive torque and the coordinate of the load and its time derivatives. Non-dimensional complex criterion (objective function), which takes into account the drive torque and its rate of change in time during the transient process, was developed to optimize the mode of the trolley movement mechanism. Based on that, a variational problem was formulated and solved in an analytical form in which root-mean-square (RMS) values of the quantiles were applied. A complex optimal mode of acceleration of the trolley movement mechanism was obtained and compared with the modes optimized based on different criteria. Advantages and disadvantages of the solutions were discussed based on the analysis of the obtained optimal modes of motion. The analysis revealed low- and high-frequency elements oscillations of the trolley movement mechanism during the transient processes. The conditions for their elimination were formulated.