Development of a Low-Cost Mechanical Hand Prosthesis with Varied Grasp Positions

The pricing of high-performance hand prostheses and grasp limitations of low-cost hand prostheses indicate a need for the creation of a cost-effective upper limb prosthesis with high-performance capabilities. The need is particularly relevant for pediatric recreational applications, as it is difficult to finance multiple high-performance devices to match the growth of a child.

We propose a low-cost upper limb prosthesis, the HelpingHand, to address these concerns through modification of the publicly available e-NABLE Phoenix Hand v2. Custom flexible finger modules and a user-adjustable whippletree mechanism were developed, allowing for swapping between power and precision grasp positions based on selected tension levels. The two designs were then compared through user performance tests with various common household objects and grasp positions.

The HelpingHand device features wrist actuation and incorporation of various adjustable power and precision grasp patterns with a material price point of under $10. In addition, bioinspired flexible finger modules were created to improve device grasp functionality. User tests demonstrated improvements in device performance in both power and precision grasp positions over current low-cost prosthetic standards.

Implementation of user-adjusted grasp positions in an upper limb prosthesis developed with accessible manufacturing methods represents a promising step forward in low-cost device development. With further optimization and validation, the HelpingHand could provide an advancement in low-cost recreational prosthetic technology.