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- Autors
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Loveikin V., Romasevych Yu., Krushelnitsky V.
- Issue
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Hoisting and transport equipment, 2019, №1(60)
- Pages
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46-58
- DOI
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10.15276/pidtt.1.60.2019.05
- Abstract
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The article is devoted to the optimization of the control of movement of a crane with a load on a flexible suspension. In order to state the problem, an integral criterion has been used which reflects unwanted system’s features. In order to carry out the calculations, the mathematical three-mass model of the crane movement has been used. It takes into account the oscillation of the load and elastic vibrations of the crane metal construction. The optimization problem also takes into account the boundary conditions of the reduced masses of the crane and a load, which ensure the elimination of the load oscillations (the boundary conditions correspond to the crane acceleration). The solution of the problem has been found using the classical variational calculus: the necessary minimum condition for an integral functional – the Euler-Poisson equation has been found. It is represented by a homogeneous differential equation of the twelfth order. The solution of the equation has been found in analytical form. The performed analysis of the results of the problem solution shows that the level of dynamic forces in the elements of the crane is insignificant. In addition, the effect of the duration of the controlled mode of motion on level of dynamic forces is established.
The realization of optimal control has been carried out by modern means of microelectronics and a controlled electric drive. In order to take into account the variations of the system "crane-load" parameters a close-loop block has been developed. It allows obtaining information from sensors of the length of the flexible suspension, weight of a load and operatively transmitting data to the system's microcontroller. Specialized software has been developed. It allows, taking into account the actual parameters of the controlled system, to calculate the optimal modes of starting and stopping of the crane. Another function of the developed software is to control the frequency converter, which acts as a power source for the electric drive crane movement mechanism. It has been implemented by sending to the frequency inverter control signals in relation to the power supply voltage frequency of the drive motor.
- Keywords
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bridge crane, system of control, optimization, dynamic forces.
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