Active Vibration Suppression of the Wind Tunnel Model Support Structure by Positive Position Feedback Controller with Robust Phase Compensator

In wind tunnel tests, to reduce the aerodynamic interference, the slender cantilever sting structure is usually used to support aircraft models. Due to its low structural damping, harmful low-frequency vibration often occurs during wind tunnel tests which leads to the degradation of data accuracy and test safety, as well as the limitation of test envelope. To ensure the wind tunnel testing capability and improve the data quality, an active vibration suppression system based on piezoelectric stack actuators is developed in this paper. A sting-root active damping device composed of four piezoelectric stacks is designed to suppress the vibration of the cantilever sting in the pitch plane. Meanwhile, the working principle and dynamic model of the active vibration suppression system is analyzed. Furthermore, considering the phase deviations in the control system and the structural natural frequency variation problem, a positive position feedback (PPF) controller with a robust phase compensator (RPC) is proposed to realize stable vibration mitigation performance. To verify the feasibility and validity of the active vibration suppression system, a series of experiments are conducted in the laboratory. Experimental results show that the vibration of the wind tunnel model support structure can be effectively suppressed with a high convergence rate under different excitation conditions and natural frequency variations, which indicates the superior damping and robustness performance of the proposed piezoelectric-based active vibration suppression system.