ADAPTIVE CONTROL OF VIBRATOR

Abstract

Vibration Test is a part of basic environmental testing of electronic-and electerical items and components. -Vibration test (IS:9001, Part XIII-1981) determines the ability of electronic and electrical items to withstand specified severities of vibration. The vibration test with an antilogarithmic sweep rate of 1 octavehnin and a frequency range of 10-150-10 Hz is developed. The vibration test developed in this work is to test the Energy Meters, hence the seventies-of vibrations as per IS:13010-1.990 are followed. The amplitude of ,vibrations . is =controlled and maintained constant at 2mrn peak in constant displacement range and ,2.2g peak in constant acceleration range. Vibrator, on which the meter under testis placed has an input-output response characteristics which varies with frequency and weight placed on it. Hence, displacement and. acceleration of vibrations generated by vibrator changes for same input excitation with varying frequency & mass. The purpose of this work is to generate the desired. excitation signal i.e. a signal having an antilogarithmic frequency sweep rate of 1 octave/min over a frequency range of 10-150-10 Hz, which produces the required displacement and acceleration amplitudes of vibrations. For this, the parameters of the transfer function of the vibrator system are roughly estimated to cover the frequency and mass dependency. Displacement and accelerationare monitored with the help of accelerometer. First the open loop control of input excitation is done and the output acceleration is monitored. Then the closed loop PID control is used for controlling the input excitation to -get displacement and acceleration to a specified constant value. The developed software is giving satisfactory results and is independent of the characteristics of the vibrator, pay load and frequency range.