Toward improving control performance of myoelectric arm prosthesis by adding wrist position feedback

Area of Science:

• Biomedical Engineering
• Rehabilitation Technology
• Prosthetics

Background:

• Many limb amputees reject myoelectric prostheses due to a lack of sensory feedback.
• Current prostheses rely solely on visual feedback (Vis-FB), hindering precise wrist control for daily activities.
• Accurate wrist positioning is crucial for effective manipulation in activities of daily living (ADLs).

Purpose of the Study:

• To design and evaluate a myoelectric arm prosthesis incorporating wrist position feedback (WP-FB).
• To investigate the impact of WP-FB on prosthetic control accuracy and success rates.
• To compare the effectiveness of Vis-FB, WP-FB, and combined Vis-FB and WP-FB (VP-FB).

Main Methods:

• Developed a myoelectric arm prosthesis with integrated WP-FB using an armband with vibrating motors.
• Conducted a vibrotactile perception range test to determine optimal feedback parameters.
• Performed a sensory feedback test with six able-bodied subjects performing 20 movement combinations across five target positions.

Main Results:

• Addition of WP-FB reduced the absolute angular error (AAE) of the prosthetic wrist from 4.50° to 1.08°.
• The success rate (SR3) for prosthetic wrist control increased from 0.34 to 0.84 with WP-FB.
• VP-FB demonstrated superior performance compared to Vis-FB alone.

Conclusions:

• Wrist position feedback (WP-FB) is crucial for enhancing the control of myoelectric arm prostheses.
• Implementing WP-FB significantly improves prosthetic wrist accuracy and user success rates.
• This technology offers a promising solution to improve prosthesis acceptance and functionality for amputees.