Hydraulic square-wave pressure generator with a specific rotating valve

This study presents a novel hydraulic square-wave pressure generator whit a specific rotating valve that generates periodic square-wave pressure at low frequency to enable the frequency response method to be applied to dynamic calibration. The most important concern is how to expand the bandwidth of generated square-wave pressure using a specific rotating valve. In addition to functioning as damped vibration, the pressure transient of the generated pressure has a major role in increasing bandwidth. Furthermore, the rotating valve effectively hinders interference from the pressure source and decreases the rise time of the pressure transient. Experimental results indicate that the pressure transient of the generated pressures rapidly converges toward the steady state such that the waveform of generated pressure approaches a square waveform, when the generator operates between 10 and 30 Hz. The bandwidth of the generated pressures is analyzed at 1 kHz. Therefore, the hydraulic square-wave pressure generator generates signals and is appropriate as a function generator to evaluate the dynamic performance of hydraulic components with low frequency resonance.