This thesis is centered upon the published A Novel Method and Exoskeletons for Whole-arm Gravity Compensation (Turner, Hull 2020), and includes a novel concept for supporting the weight of a person's arm or robotic linkage. The design is capable of supporting weights held near the hand, and provides support regardless of position. This support is provided with a pantograph. The upper-arm and forearm bars are mirrored by smaller copies. Force applied to a pull point on the scaled copy of the arm is flipped and applied at a support point on the forearm or to a tool near the hand.
Two exoskeletons, using different linkages make use of the pantograph design. These include the Panto-Arm Exo, which uses it's slim, reduced size to comfortably assist users in lifting their arm, and the Panto-Tool Exo which is designed for a support point that coincides with a mass representing a heavy tool. The differing topologies and purposes of these two devices resulted in different qualities regarding their ability to lift weight. The Panto-Arm Exo was specifically used in human subject testing, in which fourteen users wore electromyography electrodes and performed simple arm movements and holding tasks. While the Panto-Arm Exo did not undergo stringent design improvements or user-specific optimization, the device was shown to reduce muscle use in the measured upper-arm muscles for certain arm positions. / Master of Science / This thesis is centered upon the published A Novel Method and Exoskeletons for Whole-arm Gravity Compensation (Turner, Hull 2020), includes a new way to lift a person's arm or robotic linkage. The design can lift weights close to the hand regardless of arm placement. This support is provided with a pantograph. The pantograph design is based on a mirrored, smaller copy of the upper-arm and forearm bars, which is pulled downwards to create an upwards support force at chosen support point. This point is based underneath the forearm or at a heavy tool. The concept is similar to pushing down on a teeter-totter in order to prevent the other end from dropping.
Two exoskeletons, using different linkages make use of this pantograph design. The Panto-Arm Exo is slim and light. It is made to help users in lift their arm by supporting its weight. The Panto-Tool Exo has a support point that located where a mass representing a heavy tool sits. The changes between both devices means that they display different lifting qualities. The Panto-Arm Exo was worn by 14 people, also wearing electrodes that measured muscle activation. These users held weights and moved their arms around while muscle activation was recorded. While the Panto-Arm Exo wasn't fine-tuned or adjusted for individual people, it was shown to reduce muscle activation in the measured upper-arm muscles for some of the arm placements.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/103860 |
| Date | 14 June 2021 |
| Creators | Turner, Ranger Christian Kelly |
| Contributors | Mechanical Engineering, Asbeck, Alan T., Sandu, Corina, Nussbaum, Maury A. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis |
| Format | ETD, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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