Research On Resonance Suppression Method For Electro-hydraulic Flight Simulation Turntable

Electro-hydraulic flight simulation turntable is the key equipment used to evaluate guidance system merits in hardware in the loop system. As the increase of the aircrafts’ inertia and performance target, the whole body of flight tuentable is getting huger and huger and the simulation turntable usually needs to be bonded to a high base, so the natural frequency turns to be very low. During the testing process of the flight turntable, high frequency sine sweep experiments are taken frequently so the hydraulic natural frequency point and mechanical natural frequency point are easily reached with the increase of sweep signal’s frequency. The whole system will appear resonance phenomenon when the frequency of sweep signal is close to or achieve natural frequency, which will cause mechanical structure of the turntable vibrate violently and even cause permanent damages. Therefore, it is very significant to study how to reduce the resonance at the hydraulic natural frequency point and the mechanical natural frequency point through control methods.Based on the current status of the study both in and abroad country, determine the following research contents:Firstly, establishes mathematical model which considers the mechanical stiffness in the hydraulic position system and analyzes the resonance peak that appears at the hydraulic natural frequency point and the mechanical natural frequency point through the transfer function and Bode diagram. The acceleration loop has been designed using the root locus way and the damping ratio has b een increased in the hydraulic system, which inhibit the emergence of hydraulic resonance peak. At the same time the lag correction in position loop and feed-forward control method have been designed, which enables the system to achieve better performances.Secondly, the influence of various parameters of notch filter on the notch performance has been studied, and then the notch filter which will attenuate the resonance peak at the mechanical natural frequency point has been designed. The turntable’s six orders modal and vibration mode have been obtained and the most violent vibration position when resonance occurs has been analyzed through analyzing the modal of three-axis electro-hydraulic flight turntable’s mechanical structures.Thirdly, examines the effect of the control methods designed in this paper through experiments. Based on this, examines the suppression effect of the acceleration feedback for hydraulic resonance and the notch filter for mechanical resonance separately through sine sweep output.