DESIGN OF CONTROLLER FOR SHAKER

Abstract

This work presents the main results of a novel acceleration controller designed for acceleration control of an electrodynamic shaker. Vibration testing is performed to provide the test item vibration environments expected in its shipment and application environment. It is important and mandatory to do vibration testing for testing the mechanical reliability of articles. It is equally important that the test specifications are properly assessed; else it can lead to damage of the test item. In this thesis work a linear power amplifier fed electrodynamic shaker is utilized to perform vibration testing. For this work the mathematical model of the shaker along with the power amplifier. is obtained. A feedback loop is augmented along with the feed forward loop to control the acceleration levels of the shaker and also to smoothen out the shaker output waveform, making it more sinusoidal. The tests are conducted in open-loop and in closed-loop for both no-load and loaded conditions. The results so obtained are compared and it is observed that better control is achieved in closed-loop system. Smoothening of waveform due to reduction of harmonic content and lesser percentage of steady state error in the magnitude is observed in the case of closed-loop control. The reasons for errors and limitations of the employed method are discussed and some suggestions are made to improve the overall performance of the system.