Active structural acoustic control of composite fairings using single-crystal piezoelectric actuators

Abstract

This paper investigates active control using single-crystal piezoelectric actuators for reducing the vibration and acoustic loads occurring in payload fairings during launch. These numerical studies imposed reasonable and practical limitations on actuator mass and voltage for the closed-loop control simulations in order to provide a realistic assessment of the control approach. Fully coupled structural-acoustic models were developed with linear quadratic regulator and linear quadratic Gaussian control laws and simulated using realistic disturbance levels. The results are compared to previous studies that used conventional piezoelectric actuators and demonstrate significant improvement. The simulation results indicate that more than 10 dB of reduction in the interior acoustic response can be achieved over the 0-300 Hz bandwidth using full state feedback control. The primary reason for the performance improvement over polycrystalline piezoceramics is the increased strain coefficient, which provides increased control authority. However, performance is significantly reduced by model uncertainty and sensor noise to approximately 3 dB as indicated by linear quadratic Gaussian closed-loop results.