Wrist Prosthesis: New Two Degrees-Of-Freedom Hydraulic Wrist Mechanism for Hand Prostheses

Since there is a lack of functional active two degree of freedom wrist mechanisms for hand prostheses, one is designed in accordance to the needs of the user, such that it can be provided with hand prostheses and used by patients. A list of requirements is used to design a wrist mechanism, after which the prototype is tested to validate the design compared to the requirements. This is done with a test setup where, among others, torque and position of the mechanism are measured. A hydraulic vane cylinder is chosen as the rotation mechanism for both degrees of freedom, but only one degree of freedom is fabricated and tested as a proof of concept. The vane cylinder leaked and could not muster any significant torque. This leaking is probably caused by scratches in the surface of the cylinder wall. Other requirements could be validated despite this setback. The range of motion for instance could be achieved, only the stroke of the master cylinder had to be increased due to the compression of air. The weight, 21.2g for the fabricated working mechanism, and dimensions, 20.7mm height and 30mm diameter, of the mechanism have also been met. It can be concluded that this hydraulic vane cylinder is a promising wrist mechanism to use in hand prostheses, because it is a small and compact design, but with the recommendation to have a precise fabrication with a smooth surface finish so that the vane cylinder is not leaking.

Subject

wrist mechanism
hand prosthesis
hydraulics

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http://resolver.tudelft.nl/uuid:27b5ca40-c42f-4909-bbcd-cf60fc86f30f

Embargo date

2015-12-18

Part of collection

Student theses

Document type

master thesis

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report.pdf

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