A strength based approach for the synthesis of a compliant nonlinear spring for an orthotic knee brace

Girish Krishnan, Ryan Rank, John Rokosz, Phil Carvey, Sridhar Kota

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

Abstract

Lightweight mechanical energy-storage devices or springs with nonlinear strain-energy absorption rate are important building blocks for passive/quasi-passive rehabilitation robotics. They provide support and controllable energy storage/release into the system thereby making daily activities such as walking/running metabolically efficient for the disabled. These devices have stringent footprint constraints and must withstand 10 million cycles of loading for successful implementation on an orthotic device. Currently, there are no off-the-shelf springs or a systematic synthesis methodology that can meet these requirements in a deterministic fashion. In this paper, we demonstrate how existing body of knowledge in compliant mechanisms can be systematically leveraged to design spring geometries with distributed compliance that meet fatigue criteria and weight requirements. Towards this, we implement a strength-based approach to determine feasible initial solutions that upon optimization yield geometries with maximally distributed stresses. Such a framework is general and can be adapted for designing any compliant mechanism.

Original languageEnglish (US)
Title of host publication37th Mechanisms and Robotics Conference
PublisherAmerican Society of Mechanical Engineers
ISBN (Print)9780791855935
DOIs
StatePublished - 2013
Externally publishedYes
EventASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC/CIE 2013 - Portland, OR, United States
Duration: Aug 4 2013Aug 7 2013

Publication series

NameProceedings of the ASME Design Engineering Technical Conference
Volume6 A

Other

OtherASME 2013 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC/CIE 2013
CountryUnited States
CityPortland, OR
Period8/4/138/7/13

ASJC Scopus subject areas

  • Modeling and Simulation
  • Mechanical Engineering
  • Computer Science Applications
  • Computer Graphics and Computer-Aided Design

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