Adaptive Helmholtz Resonator in a Hydraulic System

Authors: Lari Kela

Abstract:

An adaptive Helmholtz resonator was designed and adapted to hydraulics. The resonator was controlled by open- and closed-loop controls so that 20 dB attenuation of the peak-to-peak value of the pulsating pressure was maintained. The closed-loop control was noted to be better, albeit it was slower because of its low pressure and temperature variation, which caused variation in the effective bulk modulus of the hydraulic system. Low-pressure hydraulics contains air, which affects the stiffness of the hydraulics, and temperature variation changes the viscosity of the oil. Thus, an open-loop control loses its efficiency if a condition such as temperature or the amount of air changes after calibration. The instability of the low-pressure hydraulic system reduced the operational frequency range of the Helmholtz resonator when compared with the results of an analytical model. Different dampers for hydraulics are presented. Then analytical models of a hydraulic pipe and a hydraulic pipe with a Helmholtz resonator are presented. The analytical models are based on the wave equation of sound pressure. Finally, control methods and the results of experiments are presented.

Keywords: adaptive, damper, hydraulics, pressure, pulsating

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1332432

References:

[1] J. Mikota, "Comparison of various designs of solid body compensators for the filtering of fluid flow pulsations in hydraulic systems," Proc. of 1st FPNI-PhD Symp, Hamburg, 2000.
[2] T. J. Viersma, Studies in Mechanical Engineering I - Analysis, Synthesis and Design of Hydraulic Servosystems and Pipelines, Netherlands: Elsevier Scientific Publishing Company, 1980.
[3] L.E. Kinsler, A.R. Frey, A.B. Coppens, and J.V. Sanders, Fundamentals of acoustics, USA: John Wiley and Sons, 1982.
[4] J. Kiesbauer, Selbstpassande Pulsationminderer in Hydraulischen Systemen, Germany: Technischen Hochschule Darmstadt, 1991.
[5] H. Ortwig, "Experimental and analytical vibration analysis in fluid power systems," Int J Solids Struct, vol. 42, pp. 5821-5830, 2005.
[6] M. Ijäs, Damping of Low Frequency Pressure Oscillation. Dissertation. Tampere University of Technology, 2007.
[7] H. Matsuhisa, B. Ren, and S. Sato, "Semiactive Control of Duct Noise by a Volume-Variable Resonator," JSME, vol. 35, no. 2, pp. 223-228, 1992.
[8] L. Kela, and P. Vähäoja, "Measuring pressure wave velocity in a hydraulic system," Proc World Acad SET, vol. 37, pp. 610-616, 2009.
[9] L. Kela, "Resonant frequency of an adjustable Helmholtz resonator in a hydraulic system," Arch Appl Mech, vol. 79, pp. 1115-1125, 2009.
[10] J.M. de Bedout, M.A. Franchek, R.J. Bernhard, and L. Mongeau, "Adaptive-passive noise control with self-tuning Helmholtz resonators," J Sound Vib, vol. 202, no. 1, pp. 109-123, 1997.
[11] S. Singh, C.Q. Howard, and C.H. Hansen, "Tuning a semi-active Helmholtz resonator," Active 2006, Adelaide, Australia, 12 pp., 2006.
[12] M.A. Franchek, M.W. Ryan, and R.J. Bernhard, "Adaptive passive vibration control," J Sound Vib, vol. 189, no. 5, pp. 565-585, 1995.