Method And Experiment Research On The Active Vibration Control Of Wind-tunnel Model With Sting Support

The sting support model is frequently adopted in transonic wind-tunnel test with high angle of attack conditions. Such support system has low stiffness and is prone to severe low frequency vibration under the aerodynamic fluctuating force, which directly influencing the dynamometer test results and safety. Among the active and passive suppression methods for the model-sting vibration system, the active one with piezoelectric ceramic actuators has better suppression effect. This thesis analyzes the anti-vibration principle as a basis and proposes a sleeve-style active anti-vibration structure with piezoelectric ceramic stack actuators. What’s more, A real-time control system is built and an experiment for the suppression system performance is carried out.(1) The principle of piezoelectric effect and output characteristics of piezoelectric stack actuators are firstly introduced, and accompanied with the mechanics analysis of the sting deformation, the actuator-to-deformation formula is derived. This deformation is used to reduce the deflection by the fluctuating aerodynamic loads at the end of the sting. Based on this theory and focused on a domestic model-sting system, a sleeve-style structure damper is designed and its installation layout is optimized. A simulation analysis of the static performance of the damper is applied to verify the rationality of the equation derived and damper structure designed.(2) Based on the characteristics of wind-tunnel aerodynamic loads, a set of close-loop control system is composed, including the sting vibration measurement, signal processing and amplifying, and actuators to drive reverse displacement. A high real-time hardware is equipped for the active damper, and a PD controller based program with forward compensation ability is designed to solve the driving displacement lag issues. To evaluate the performance of the active anti-vibration system, hammering method and vibration method is proposed with the related evaluation means, and a corresponding ground experiment platform is constructed.(3) In the ground experiment study for the anti-vibration system, its basic output performance is obtained, which is close to the theoretical calculations and static simulation results. The experiments by hammering method and vibration method show that the damper designed can improve the damping ratio of the sting and suppress model vibrations on both pitch and yaw directions. On the pitch direction, the damping ratio of the system increases from0.009up to0.092when the suppressor involves and the lowest proportion of remained vibration amplitude is19.7%. The temperature drop phenomenon in wind-tunnel tests has negative impact on the active damper, which is explored in this paper, and by tuning new parameters of the control system, this impact can be compensated to a certain degree.