22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-4.9.3

ACTIVE CONTROL OF FLEXIBLE STRUCTURES BASED ON FUZZY LOGIC

K. Cohen, T. Weller, J. Z. Ben-Asher
Department of Aerospace Engineering, Technion – I.I.T., Israel

Keywords: fuzzy logic, flexible structures, active control, vibration suppression

This study deals with the development and implementation of an active control law for the vibration suppression of beam-like flexible structures experiencing transient disturbances. Collocated pairs of sensors/actuators provide active control of the structure. A design methodology for fuzzy logic based closed-loop control algorithm of beam vibration is proposed. First, the behavior of the open-loop system is observed. Then, the number and locations of collocated actuator/sensor pairs are selected. The proposed control law, which is based on the principles of passivity, commands the actuator to emulate the behavior of a dynamic vibration absorber. The absorber is tuned to a targeted frequency, whereas the damping coefficient of the dashpot is varied in a closed loop using a fuzzy logic based algorithm. This approach, not only assures inherent stability associated with passive absorbers, but also circumvents the phenomenon of modal spillover. The developed controller is applied to the AFWAL/FIB ten bar truss. Simulated results using MATLAB show that the closed-loop system exhibits fairly quick settling times and desirable performance, as well as robustness characteristics.

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