Optimized Sythesis of a Force Generating Planar Four-Bar Mechanism Including Dynamic Effects

This thesis presents a technique for designing planar four-bar linkages by coupling optimization, dynamics and kinematics. This synthesis technique gives the designer the ability to design linkages having a desired resistance profiles under an assumed motion profile. The design approach presented in this thesis calculates the resistance forces by using both the static and the anticipated dynamic effects of the resistance loading. Almost all research to date has assumed that the static forces in the linkage dominate the dynamic forces; hence, the dynamic effects have been neglected. This thesis shows that this assumption is often invalid. The traditional approach for designing resistance-generating mechanisms has been based on closed-form methods that attempt to exactly match the resistance at a small number of discrete positions. This work uses a numerical optimization method that allows for the matching of the entire resistance curve by approximately matching a set of positions that define the shape of the curve. This work furthers the discipline of mechanism design by combining dynamics into existing linkage synthesis methods, resulting in an improved synthesis method that includes both static and dynamic effects. While this approach can be used in many applications, this work focuses on the design of exercise equipment. This focus is because exercise equipment designed to optimally stress a specific muscle group usually have a specific " strength curve " used to design the resistance load. The "strength curve" is the locus of all maximum loads moveable by the exerciser in all body part positions over the full range of motion. This application ideally suits the specification of the problem addressed in this thesis.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2001

Author dc:creator

• Rundgren, Brian Tavis

Chair dc:contributor.committeechair

• Reinholtz, Charles F.

Committee members dc:contributor.committeemember

• West, Robert L. Jr.
• Mitchell, Larry D.

• Kinematics
• Force Generation
• Linkages
• Synthesis
• Mechanisms
• Optimization

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-12102001-103158

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/36042