Active Vibration Control of Flexible Structures Using Genetic Optimisation

Abstract

This paper presents an investigation into the development of an adaptive control mechanism for vibration suppression of flexible beam structures using genetic algorithms (GAs). The global search technique of GA is used to estimate the controller transfer function, based on one-step-ahead prediction. An active vibration control (AVC) system is designed utilizing a single-input single-output (SISO) control structure to yield optimum cancellation of broadband vibration at an observation point along the beam. The mean-squared error of observed deflection is adopted as the fitness function and randomly selected controller parameters are optimised for different, arbitrarily chosen order to fit to the system by applying the working mechanism of GA. The global search technique of the GA is utilised to obtain the best parameters among all attempted orders for the controller. The GA-AVC algorithm thus developed is implemented within the simulation environment of a flexible beam structure and simulation results are presented to assess the performance of the system, with different types of excitation namely pseudo-random binary sequence, uniform random and finite duration step signals. It is noted that, the system performance is satisfactory and significant amount of vibration reduction over a broad range of frequencies of the input signal is achieved.