A Wearable Testbed for Studying Variable Transmission in Body-Powered Prosthetic Gripping

Area of Science:

• Biomedical Engineering
• Rehabilitation Engineering
• Prosthetics and Orthotics

Background:

• Body-powered prostheses are popular for upper limb absence due to haptic feedback and robustness.
• Current body-powered graspers use constant transmission, which can cause user strain and fatigue.
• Robotic hand research shows continuously variable transmissions (CVTs) offer adaptable grasping speeds and strength.

Purpose of the Study:

• To integrate a CVT into a body-powered prosthetic hand testbed.
• To evaluate the performance of a CVT-equipped prosthetic gripper.
• To reduce shoulder exertion and fatigue in users of body-powered upper limb prostheses.

Main Methods:

• Designed and built a prosthetic testbed incorporating a CVT.
• Validated performance through benchtop experiments comparing constant vs. CVT conditions.
• Utilized a prosthetic emulator for preliminary wearable testing.

Main Results:

• The CVT system demonstrated the potential for force-dependent, continuously varying grip force.
• Benchtop experiments validated the CVT's performance in a prosthetic emulator.
• Preliminary results suggest reduced user exertion compared to constant transmission systems.

Conclusions:

• Integration of CVTs into body-powered prosthetics is feasible.
• CVTs offer a promising approach to mitigate strain and fatigue in upper limb prosthesis users.
• Further research and development could enhance the functionality and comfort of prosthetic devices.