0

Full Content is available to subscribers

Subscribe/Learn More  >

Dynamic Model of a Hybrid Hydraulic Actuator Utilizing Different Smart Materials

[+] Author Affiliations
A. Chaudhuri, N. M. Wereley

University of Maryland, College Park, MD

Paper No. IMECE2007-42557, pp. 193-202; 10 pages
doi:10.1115/IMECE2007-42557
From:
  • ASME 2007 International Mechanical Engineering Congress and Exposition
  • Volume 10: Mechanics of Solids and Structures, Parts A and B
  • Seattle, Washington, USA, November 11–15, 2007
  • Conference Sponsors: ASME
  • ISBN: 0-7918-4304-1 | eISBN: 0-7918-3812-9
  • Copyright © 2007 by ASME

abstract

There has been a lot of research in the development of a hybrid hydraulic actuator driven by various smart materials. The basic operation of these actuators involves high frequency bidirectional operation of the active material which is converted to unidirectional motion by a set of valves. The response of the actuator also shows resonant peaks similar to that of SDOF mechanical systems and indicates a region of maximum output. At these high driving frequencies, the inertial effects of the fluid mass dominate over the viscous effects and the problem becomes unsteady in nature. Geometrical parameters of the flow path are also important. Due to the high pressures existing inside the actuator and the presence of entrained air, compressibility of the hydraulic oil also has to be taken into account. Hybrid actuators using the magnetostrictive material Terfenol-D and the electrostrictive material PMN have been developed in our laboratory, with hydraulic oil as the working fluid. Several key design parameters, which include output cylinder size, diaphragm thickness, reed valve thickness and tubing diameter, along with operational conditions, like input current and bias pressure within the fluid, have been varied to identify a set of optimum driving conditions. Tests at no-load and with load have been carried out for unidirectional motion of the output piston. To characterize the input driving circuitry and magnetic flux path, we have also carried out dynamic tests with the Terfenol-D rod and analyzed its magnetic circuit (flux density vs. frequency) response. In this paper, we develop a mathematical model of the hydraulic hybrid actuator to show the basic operational principle under no-load and loaded conditions and to describe the resonance phenomenon affecting the system performance. The dynamics of the input driving circuit have been included in the model. The fluid passages have been represented using the transmission line model, giving rise to strongly coupled ordinary differential equations which are solved using a lumped parameter approach. This model is then used to calculate the no-load velocity of the actuator and also its blocked force. Finally, we use the model to find optimal pumping frequency to get highest performance with different active materials and also to predict the pump sizing for desired output velocity and load lifting capability.

Copyright © 2007 by ASME

Figures

Tables

Interactive Graphics

Video

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In