Thesis Type: Postgraduate
Institution Of The Thesis: Orta Doğu Teknik Üniversitesi, Faculty of Engineering, Department of Mechanical Engineering, Turkey
Approval Date: 2013
Student: İBRAHİM FURKAN LÜLECİ
Supervisor: HASAN NEVZAT ÖZGÜVENAbstract:
Conformal airborne antennas have several advantages compared to externally mounted antennas, and they will play an important role in future aircrafts. However, they are subjected to vibration induced deformations which degrade their electromagnetic performances. With the motivation of suppressing such vibrations, use of active vibration control techniques with piezoelectric actuators is investigated in this study. At first, it is aimed to control the first three bending modes of a cantilever beam. In this scope, four different modal controllers; positive position feedback (PPF), resonant control (RC), integral resonant control (IRC) and positive position feedback with feed-through (PPFFT) are designed based on both reduced order finite element model and the system identification model. PPFFT, is a modified version of PPF which is proposed as a new controller in this study. Results of real- time control experiments show that PPFFT presents superior performance compared to its predecessor, PPF, and other two methods. In the second part of the study, it is focused on controlling the first three modes of a rectangular plate with four clamped edges. Best location alternatives for three piezoelectric actuators are determined with modal strain energy method. Based on the reduced order finite element model, three PPFFT controllers are designed for three collocated transfer functions. Disturbance rejection performances show the convenience of PPFFT in multi-input multi-output control systems. Performance of the control system is also verified by discrete-time simulations for a random disturbance representing the in-flight aircraft vibration characteristics.