The lightweight Delft Cylinder Hand: first multi-articulating hand that meets the basic user requirements

Area of Science:

• Biomedical Engineering
• Rehabilitation Technology
• Prosthetics Design

Background:

• High rejection rates (23%-45%) for upper limb prostheses are linked to design issues.
• Current prosthetic hands are heavier (35%-73% more mass), thicker, slower, and lack sensory feedback compared to human hands.
• Reducing prosthetic device mass is a top priority for amputees.

Purpose of the Study:

• To present the Delft Cylinder Hand, a novel body-powered prosthetic hand.
• To address the limitations of current prosthetic hands, including mass, speed, form factor, and sensory feedback.
• To evaluate the mechanical performance and user energy requirements of the new prosthetic hand.

Main Methods:

• Development of a body-powered prosthetic hand actuated by miniature hydraulic cylinders.
• Design featuring articulating fingers that adapt to grasped objects.
• Evaluation of functional scores, mechanical performance, user energy expenditure, and pinch force.

Main Results:

• The Delft Cylinder Hand's mass is 55%-68% lower than current lightest prosthetic hands.
• The hand operates faster, possesses an anthropomorphic shape, and provides proprioceptive force and position feedback.
• Functional scores are comparable to current devices, with significantly reduced user energy requirements (49%-162% less) and higher maximum pinch force (30-60 N).

Conclusions:

• The Delft Cylinder Hand offers substantial improvements in mass reduction, speed, and sensory feedback compared to existing prosthetics.
• The design achieves higher mechanical performance and efficiency, requiring less user energy.
• This novel prosthetic hand presents a promising advancement in upper limb prosthetics for amputees.