Multi-modal vibration control method combining modal decoupling and active disturbance rejection for wind tunnel models

When excited by broadband wind load, the wind tunnel model support system with low stiffness and damping is easy to produce multi-modal coupling vibration. It not only leads to inaccurate experimental data but also has potential safety hazards. Therefore, to ensure the reliable development of wind tunnel tests, a multi-modal vibration control method with multi-damping is proposed. Firstly, a multi-damping vibration suppression structure is designed based on the vibration analysis results. Next, the modal filter is designed by identifying the modal decoupling matrix, which can get the independent feedback signals of each mode. Then, considering the external disturbance of the environment and the internal disturbance between dampers, a multimodal linear active disturbance rejection controller is designed to control the vibration and total disturbance. Finally, the multi-modal vibration suppression system of the UAV model is built, and the sweep frequency identification and hammering experiment are carried out. The results show that the proposed method can reduce the power spectral density of the first and second modes by 42.500 dB/Hz and 12.442 dB/Hz respectively, and increase the damping ratio by 14.659 times and 2.898 times respectively. Compared with the traditional control methods, the proposed method possesses obvious advantages in multi-modal vibration control. Therefore, ensured that wind tunnel tests were conducted smoothly.