SYNTHESIS OF FRACTIONAL ORDER CONTROLLERS FOR MULTI-LUPP CONTROL STRUCTURE OF FIRE LIFT BASKET TURNING

Abstract

Introduction. The attempt to get the best dynamic and static characteristics of the basket turn angle complicates the tasks performed by the automatic control system (ACS) basket turn drive. The ACS  of the basket turn should meet the following requirements: high speed, smooth acceleration and breaking of the motor, static and dynamic accuracy of the reproduction of tasks trajectories, no overregulation in transition modes, required stability reserve, low sensitivity to coordinate and parametric disturbances, etc. A number of fundamentally different ACSs and methods for their synthesis have been analyzed to provide these requirements. As a result of the analysis, there has been selected a two-loop feedback control system (FCS) of the basket turn with regard to the elastic properties of the arrow, which is synthesized by the method of the generalized characteristic polynomial. Studies have shown that this system allows to provide an aperiodic transition process of the basket turn angle with a given speed and low sensitivity in steady state to the perturbation effect. However, the synthesized FCS transfer functions of the controllers of angular velocity of the motor and the basket have a high order and turned out to be quite complicated in terms of practical implementation. Purpose. In the article it is proposed to replace these controllers, by approximating them through evolutionary methods, with more compact fractional PІλDμ-controllers or fractional order controllers. Results. The studies carried out in this work have shown that fractional order controllers are quite advantageous in comparison with the over classical ones, particularly in the case of their application for optimization of electromechanical systems with the following features of their control objects: two masses, including those with the presence of impact; backlash viscosity of the drive friction; nonlinear load and so on. Replacement of the high-order motor and basket angular speed controllers with more compact PІλDμcontrollers or fractional order controllers has been performed using Optimization Toolbox optimization package in the MATLAB package. This software has been developed for approximation of classical parts with high-order transfer functions by fractional order parts, using a genetic algorithm or a particle swarm optimization for their transition functions. Conclusion. The conducted research on digital models has confirmed the efficiency of the replacement of high-order motor and basket angular velocity controllers with PІλDμ-controllers or fractional order controllers, whose transfer functions are determined by approximating the transition functions of the controllers by the genetic algorithm method.