PARAMETRIC OPTIMIZATION OF FREQUENCY-CONTROLLED START-UP OF DYNAMIC SYSTEM "TROLLEY-LOAD" OF TOWER CRANE TROLLEY MOVEMENT MECHANISM

Abstract

In the scientific article, a scientific and applied problem is solved, which allows to minimize the dynamic and energy parameters of the frequency-controlled drive of the dynamic "cart-load" system of the tower crane flight change mechanism during the transient start-up mode. To solve this problem, the existing mathematical model of the change in the departure of the load was used, which was supplemented by a mathematical model of the motion of an asynchronous electric drive in time. The parameters for setting the frequency-controlled drive are used: the duration of the increase in the frequency of the supply voltage, the initial supply voltage of the electric motor and the type of characteristic of the increase, up to the nominal value, of the frequency of the supply voltage. The maximum values of the torque in the elastic coupling, the effort in the traction rope and the power in the electric drive were used as optimization criteria. Using the modified RING-ROT-PSO optimization method, the rational values of the given parameters and the type of characteristic are established, in which the minimization of the studied criteria is observed. A comparative analysis of discrepancies when varying different types of characteristics was performed, which proved the adequacy of the performed parametric optimization. Parametric optimization of the frequency-controlled electric drive was carried out, which made it possible to minimize the amount of undesirable dynamic (torque in the elastic coupling and force in the traction rope of the truck drive) and energy (power in the drive) characteristics of the dynamic "cart-load" system of the mechanism for changing the departure of the tower crane. A modified method of swarm particles (RING-ROT-PSO) was used for optimization. It was established that the minimum values of dynamic criteria when using optimal characteristics (linear and 2S-shaped) in the range of 6.9...27.9% are smaller than when using non-optimal (U-shaped and S-shaped) characteristics. The minimum value of the energy criterion when using a U-shaped characteristic is 30.4% less than when using an S-shaped characteristic. Therefore, in order to minimize the amount of unwanted dynamic indicators during the frequency-controlled start of the dynamic system "cart-load" of the departure change mechanism, it is desirable to use linear and 2S-like characteristics, and to minimize the amount of unwanted energy indicator, U-shaped. At the same time, it is also necessary to rationally set parameters t1 and U0.