Characterization of Lightweight, Low-Force Cable and Hydraulic Transmission Systems
2022-08
Loading...
View/Download File
Persistent link to this item
Statistics
View StatisticsJournal Title
Journal ISSN
Volume Title
Title
Characterization of Lightweight, Low-Force Cable and Hydraulic Transmission Systems
Authors
Published Date
2022-08
Publisher
Type
Thesis or Dissertation
Abstract
In the field of rehabilitation robotics and wearable exoskeletons, a common challenge forsystem designers is how to transmit force from the actuators to the joints. In small-scale
applications, for the working range of 50-500 N, cables and hydraulics are the two most
common ways to transmit force. This study characterized wire rope, braided synthetic line,
Bowden cable, and hydraulic transmission types based on their size, weight, efficiency,
and controllability. Analytical and experimental methods were used to evaluate individual
aspects of each transmission. Analysis was performed to compare the transmission types.
The rate at which cables increase in size and weight is approximately linearly with rated
load; however, cable construction had the largest influence on the rate of increase. It was
observed that cable stiffness can be fit to a 1/L model in the approximate range of 20 to
50 cm, but not for much longer lengths. Hydraulic stiffness was modeled, and it was shown
for small diameter actuators the stiffness is comparable to the cables studied. Cable
efficiency was studied using the capstan equation and found to be Coulomb friction
dependent decreasing as wrap angle or coefficient of friction increased. Bowden cable
efficiency is also friction dependent, however Bowden cables do not follow the capstan
equation. Over-constrained Bowden cable paths led to more surface contact and decreased
efficiency. Hydraulic transmission efficiency is dependent on hose diameter and flowrate.
Optimal designs operate at high working pressures and low flowrates. It was shown in a
case study that the optimal transmission type is often application dependent.
Keywords
Description
University of Minnesota M.S.M.E. thesis. 2022. Major: Mechanical Engineering. Advisor: William Durfee. 1 computer file (PDF); 62 pages.
Related to
Replaces
License
Series/Report Number
Funding information
Isbn identifier
Doi identifier
Previously Published Citation
Other identifiers
Suggested citation
Kivi, Andrew. (2022). Characterization of Lightweight, Low-Force Cable and Hydraulic Transmission Systems. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/243040.
Content distributed via the University Digital Conservancy may be subject to additional license and use restrictions applied by the depositor. By using these files, users agree to the Terms of Use. Materials in the UDC may contain content that is disturbing and/or harmful. For more information, please see our statement on harmful content in digital repositories.