Dynamic portrait calculation of the systems with spatial oscillations

Abstract

Vibration transport and technological machines with unbalanced vibration exciters based on asynchronous electric motors (vibrating conveyors, vibrating screens, vibrating feeders, etc.) are widely used in modern industry. One of the promising ways to improve the energy efficiency of such machines is the use of the resonant mode of its working body oscillations. To ensure stable operation of such vibration machines in the vicinity of resonant frequency, it is necessary to automatically change the disturbing force frequency in accordance with the change in the system natural frequency when the mass of the technological load changes. One of the possible algorithms for controlling the disturbing frequency is based on the use of a “dynamic portrait” of the system, which is the calculated dependence of the phase shift between the driving force and the working body vibrations on the mass of the technological load (natural frequency of the system) and the vibration exciters supply frequency. The practical implementation of such algorithm is based on measuring the parameters of the working body vibrations, the supply frequency and the rotation angles of the vibration exciters rotors, which makes it possible to calculate the current value of the phase shift between the disturbing force and the working body vibrations. According to the dynamic portrait of the system, the current value of the technological load mass (natural frequency of the system) is calculated and the corrective value of the vibration exciter power supply frequency corresponding to the resonant oscillation mode is determined. The aim of this work is to construct dynamic portraits of vibration machines with self-synchronizing vibration exciters and spatial vibrations of the working body.