Optimization and design principles of a minimal-weight, wearable hydraulic power supply

Jonathan D. Nath, William K. Durfee

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


The field of wearable hydraulics for human-assistive devices is expanding. One of the major challenges facing development of these systems is creating lightweight, portable power units. This project's goal was to develop design strategies and guidelines with the use of analytical modeling to minimize the weight of portable hydraulic power supplies in the range of 50-300 W. Steady-state, analytical models were developed and validated for a system containing a lithium-polymer battery, brushless DC motor, and axial-piston pump. Component parameters such as motor size, pump size, and swashplate angle were varied to explore and develop four main design guidelines that can be used by designers to minimize overall system weight. First, it is often not beneficial to select the smallest sized electric motor that can provide the required torque and speed. Second, cooling systems generally do not help reduce overall system weight. Third, the gearbox between the electric motor and pump should be eliminated to reduce system weight. Fourth, iterative modeling is necessary to determine the various range of particular component parameters necessary to result in a minimal-weight system. The analytical model developed takes inputs of desired flowrate, pressure, and runtime, and outputs the combination of pump size, swashplate angle, and motor size that results in a minimal-weight system. The four design principles and the computer simulation are tools that can be used to either design a fully custom, weight-optimized power supply or to aid in the selection of commercially available components for a lowweight power supply.

Original languageEnglish (US)
Title of host publicationAerospace Applications; Advances in Control Design Methods; Bio Engineering Applications; Advances in Non-Linear Control; Adaptive and Intelligent Systems Control; Advances in Wind Energy Systems; Advances in Robotics; Assistive and Rehabilitation Robotics; Biomedical and Neural Systems Modeling, Diagnostics, and Control; Bio-Mechatronics and Physical Human Robot; Advanced Driver Assistance Systems and Autonomous Vehicles; Automotive Systems
PublisherAmerican Society of Mechanical Engineers
ISBN (Electronic)9780791858271
StatePublished - 2017
EventASME 2017 Dynamic Systems and Control Conference, DSCC 2017 - Tysons, United States
Duration: Oct 11 2017Oct 13 2017

Publication series

NameASME 2017 Dynamic Systems and Control Conference, DSCC 2017


OtherASME 2017 Dynamic Systems and Control Conference, DSCC 2017
Country/TerritoryUnited States

Bibliographical note

Funding Information:
Funding provided by the National Institute of Health (NIH), grant number 1R21EB019390.

Publisher Copyright:
Copyright © 2017 ASME.


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