Full Content is available to subscribers

Subscribe/Learn More  >

Some Experimental Considerations of Stage Control in Digital Valves

[+] Author Affiliations
J. Ruan

Zhejiang University of Technology, Hangzhou, P. R. China

R. Burton, P. Ukrainetz

University of Saskatchewan, Saskatoon, Saskatchewan, Canada

Paper No. IMECE2002-39333, pp. 55-62; 8 pages
  • ASME 2002 International Mechanical Engineering Congress and Exposition
  • Fluid Power Systems and Technology
  • New Orleans, Louisiana, USA, November 17–22, 2002
  • Conference Sponsors: Fluid Power Systems and Technology Division
  • ISBN: 0-7918-3631-2 | eISBN: 0-7918-1691-5, 0-7918-1692-3, 0-7918-1693-1
  • Copyright © 2002 by ASME


Because of saturation and hysteresis of magnetic materials, nonlinear characteristics are commonly experienced in servo or proportional valves. These nonlinearities can substantially affect the performance of the valve in practical applications. In the presence of magnetic nonlinearities, the output signal (displacement or force) is dependent on the input current and the sign of its derivative. If the driving current to the electrical-to-mechanical interface device changes for a number of cycles, as in a stepper motor for example, then a series of reset points will occur as the current undergoes cyclic changes. At each reset point the original starting characteristics of the system are re-established. A large number of reset points across the full stroke of the spool results in a significant reduction in the nonlinear behavior; indeed, the characteristics of the valve approach those of a linear system. The approach in creating these multiple reset points has been defined by the authors as “stage control”. In this paper, stage control using variable reluctance and hybrid stepper motors is first discussed. For the variable reluctance stepper motor, the reset point occurs once at each step of the stepper motor, whereas it occurs twice in a single cycle in the hybrid types. Experiments using a spool valve as a load were designed to obtain the characteristics using stage control. It is demonstrated that with the introduction of stage control, nonlinearities, such as saturation and hysteresis, are greatly reduced, system stiffness is increased, and the positioning accuracy and resolution of the spool are improved. The effect of dither due to a “digital fragment” signal is also examined and found to be crucial in reducing the hysteresis and in improving the resolution accuracy.

Copyright © 2002 by ASME
Topics: Valves



Interactive Graphics


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

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