Waveform Analysis of an Electro-Hydraulic Vibrator

The frequency bandwidth of conventional electro-hydraulic vibrator is always limited to a rather narrow range. This restriction is attributed not only to the limited response capability of the servo valve but also to the electro-hydraulic servo system itself the bandwidth of which is unable to be extended. Thus, the parallel design of a two-dimensional valve (here within defined as a 2D valve) and a servo valve is adopted to control an electro-hydraulic vibrator in half-close-loop mode so that the frequency bandwidth is greatly extended and the precision control of the vibration characteristic variables such as waveform shape is preserved. The analysis and experimental results demonstrate that the waveform distortion is less than 10%, up to 2000 Hz. It was concluded that the feasibility of the half closed loop design is established for the realization of the high frequency vibration.