Analysis on vibration for a high-frequency electro-hydraulic cleaning system controlled by improved two-dimensional rotary valve

Abstract

Conventional high-frequency cleaners utilize functional materials (e.g. piezoelectric ceramics, magnetostrictive materials) excited by electrical signals to realize high-frequency vibration, even ultrasonic vibration. However, it is difficult to produce a large force without sacrificing bandwidth because of the physical characteristics of materials themselves. Therefore, a high-frequency high-power cleaner driven by electro-hydraulic excitation is proposed. Only a few studies are performed on electro-hydraulic cleaners, owing to the limitation of frequency bandwidth of the electro-hydraulic system. Thus, a rotary valve named two-dimensional valve is improved and adopted to improve high-frequency performances of the electro-hydraulic cleaner. In this article, a two-dimensional rotary valve with a linear variable differential transformer is designed, and the vibration characteristics of the electro-hydraulic cleaner controlled by this valve are discussed in detail, especially vibration acceleration, vibration frequency, and pressure amplitude. A prototype of the electro-hydraulic cleaner is modeled and both a theoretical analysis and experimental investigation are carried out. Theoretical and experimental results indicate that the electro-hydraulic cleaning system outputs sinusoidal vibration waveforms, especially in a high-frequency domain, which could realize the vibration frequency of 2669 Hz. The measured waves at different frequencies (below the resonant frequency) demonstrate different distortions compared with the sinusoidal waveform. These distortions can be associated with the hydraulic resonance. At hydraulic resonance (1903 Hz), the amplitude is increased significantly and the vibration waveform becomes more pronounced. Nevertheless, the study does provide an access to the electro-hydraulic high-frequency vibration applied in cleaning or other engineering cases.