Modeling and identification of a resonance fluid actuator

In this article, a novel piezo - hydraulic actuator exploiting resonance effects is presented. The proposed actuator relies its operation on the significant pressure built up in a fluid pipe during resonance. The actuator´s piston houses a valve which rectifies the wave´s motion into direct mechanical motion. Since pressure waves are to be examined, a model capable of capturing the wave dynamics and fluid motion is derived. A state space model derived from the compressible Navier - Stokes equations is formed by linearizing these equations followed by a discretization using the Chebyshev collocation method. The model parameters are identified using a simple adaptive algorithm based on experimental data. A feature extraction technique, incorporating the wavelet transform on the experimental and simulated data, is used to calculate the resonance frequency and damping factor of the system. Experimental studies are used to investigate the efficiency of the proposed modeling approach.