Active control of fluid pulsation based on bypass overflow principle

With the development of the aircraft hydraulic power supply system towards high pressure and large load, the periodic fluid-horne pulsation in piping readily leads to fluid-structure interaction vibration and mechanical fatigue. Because the application of passive pulsation control is not adaptive and inefficient in low frequency conditions, an active control method based on bypass overflow principle is presented. The second pressure wave produced by the piezoelectric direct drive servovalve which is placed in bypass piping counteracts the primary pressure wave in main piping. Considering the periodicity of fluid pulsation, an adaptive feedforward control method based on on-line frequency estimation is adopted, which acquires the frequency components from the pressure reference sensor and constructs the periodic reference input signals of controller using the acquired frequencies. A test platform is designed and built to validate the vibration attenuation efficiency. The experimental results show that the vibration active control method is adaptive and robust against disturbance, and can gain high pulsation attenuation efficiency.