Study On Active Vibration Control For Wind Tunnel Testing Model In Transonic Test

In order to perform the measurement of the aircraft aerodynamic forces during wind tunnel test, thetest model is usually mounted on the pitching and yawing structure by back-support method. Thecombination structure-of testing object and support system, similar to a cantilever beam, is usuallyflexible with low natural frequencies less than100Hz. During transonic testing, the fluctuation pressurecaused by the airflow distributes in the range of low frequency bandwidth, and, furthermore, thedistribution varies with different angle of attack, model geometry, and airflow Mach numbers, etc. Inthis situation, high magnitude vibration with low frequency is easily generated due to resonance of theflexible structure excited by the low frequency fluctuation pressure. This high magnitude vibrationwould contaminate the test data and even damage the instruments in a fatigue manner, and thereforeshould be suppressed.Mathematical models of the test object and support system are established by FEM and modelidentification methods respectively, and are reduced to the form of low dimensions by using the balanceand model truncation method. Then, based on the low dimension models, LQG and H controllersare designed to suppress the vibrations. Finally, simulations and experiments are carried out to verify theability of the controllers to suppress the vibrations. For different control schemes, comparisons betweenthem are given in terms of both simulation and experimental results.