Development and Control of a Multigrasp Myoelectric Hand Prosthesis

Externally powered transradial prostheses have traditionally been limited to devices that are broad abstractions of the natural hand, possessing a single degree of freedom and having limited grasping capability. Enabled by recent technological advances, multigrasp prosthetic hands with greater anthropomorphic fidelity have now begun to emerge, although the ability to communicate with and control such devices is limited. In light of these facts, the goal of the work described herein was to develop a control interface to provide full access to the capability of a multigrasp hand, and thereby enhance the ability of an amputee to perform the activities of daily living. To achieve this, a multigrasp hand prosthesis was constructed along with a state-based multigrasp myoelectric controller (MMC). Initial tests were performed by non-amputee participants in a virtual environment so that the performance of a virtual prosthesis, as controlled by the multigrasp myoelectric controller, could be compared to the performance of the native hand. Functional assessments were then performed in a laboratory setting by an amputee participant to investigate the effectiveness of the physical system, in addition to a wide variety of commercial devices, in performing the activities of daily living. This dissertation presents the results of the above work, and demonstrates that the prosthetic system provides functional utility comparable to its commercial counterparts, while allowing rapid access the full range of grasps and postures provided by a multigrasp myoelectric hand.