Output characteristics of a horizontal type electro-hydraulic excitation system with inertial loading: Modeling and experimentation

Abstract

In a conventional electro-hydraulic excitation system it is difficult to realize high frequency vibration, even though at the cost of a decreased hydraulic force. A 2D rotary valve, characterized by the spool’s simultaneous rotary and sliding motions, was improved and adopted in a horizontal type electro-hydraulic excitation system in order to improve its high frequency performance. A description of vibration characteristics is still a challenge for the excitation system with inertial loading subjected to high frequency excitation. Therefore, this paper investigated the output characteristics of this electro-hydraulic excitation system in detail. A mass force dominant excitation system was taken as an example to demonstrate those output characteristics, which was facilitated by a specially designed approximate phenomenological model. Based on this model, the analytical expressions of the excitation waveform, working frequency and some boundary values were derived and subsequently shown to be in line with the experimental data. Theoretical and experimental results indicate that the output excitation waveforms could be described using the analytical expressions, even though the measured waves demonstrate different distortions. The distortions are especially obvious when the operating frequencies are below the resonant frequency, while they are attenuated as the frequencies increase beyond the resonance. This noteworthy phenomenon is one of the manifestations of hydraulic resonance. These results and findings provide clear guidance for the understanding and designing of the electro-hydraulic excitation system with high frequency feature.