Research On Active Multi-modal Vibration Control Of Wind Tunnel Model

Wind Tunnel Model test is an important method to study aerospace vehicle aerodynamic characteristics.It is a more economical and reliable technical means to conduct Wind Tunnel Model test by using Wind Tunnel Model sting system.The active vibration control method is urgently needed to solve the severe vibration problem generated by the low-stiffness structure in Wind Tunnel Model test,so as to provide higher quality and more complete Wind Tunnel test data for the development of new aircraft models.In the study of active vibration control methods of the Wind Tunnel Model sting system,more attention is paid to the analysis of the vibration characteristics of the wind tunnel model in the pitch direction.However,unlike the cantilever beam structure,the vibration of the multi-degree-of-freedom system is a superposition of Multi-modal vibrations in different directions.When using accelerometers as vibration sensors,most researchers perform numerical integration processing on the acceleration signal and achieve active vibration control through speed feedback,which not only increases the difficulty of signal processing but also reduces the signal-to-noise ratio.In order to suppress the very directional vibration of a Wind Tunnel Model sting system,the active vibration control method was proposed based on non-collocated configuration negative acceleration feedback(NAF)control algorithm.(1)The structural modal characteristics of the Wind Tunnel Model sting system were studied by means of dynamic theory analysis,computational modal analysis and experimental modal analysis.According to the modal space theory,the vibration of the multi-degree-of-freedom system meets the principle of superposition.The computational modal analysis and experimental modal analysis mutually verify the very directional character of the lower-order modes.The main vibration directions are the pitch and yaw directions.(2)According to the system modal characteristics,the active Wind Tunnel Model vibration control system with structural coupling embedded piezoelectric ceramic stack actuators was proposed,and the circular configuration schemes of the actuators and sensors was studied.In order to meet the real-time control requirements and the very directional character of the lower-order modes,the circumferential layout of the actuators must meet the central symmetry and orthogonality.The structural coupling dampers maximizes the output bending moment in the main vibration direction.Compared with the configuration scheme of accelerometer/actuator in the different directions,the configuration scheme of accelerometer/actuator in the same direction has little effect on the system structural characteristics and the control system time lag.(3)The non-collocated configuration NAF controller was proposed according to the active vibration control system.On the basis of NAF controller,the multi-modal NAF control algorithm was studied.The dual-mode NAF control algorithm for the first two-order modes was proposed in combination with the sensor/actuator configuration schemes.Based on the principle of multi-modal NAF control algorithm,the multi-modal NAF control algorithm combined with fuzzy control is studied to solve the output ratio problem in multi-modal vibration control,and the feasibility of the algorithm is verified by simulation analysis.The experimental research was carried out through the experimental platform of active wind tunnel model vibration control system.The test shows that the dual-modal NAF control algorithm is more effective than the single-modal NAF control algorithm.The single-modal NAF control algorithm only effectively suppresses the second-order vibration mode,while the dual-mode NAF control algorithm effectively suppresses the first two-order modes.Through the dual-modal NAF control algorithm with accelerometer/actuator in the same direction,the damping ratio of the first two-order modes increases by 12.79 times and 25.84 times respectively,and the higher-order vibration modes are quickly dissipated due to their own damping attenuation.