The optimal controller delay for myoelectric prostheses.

Area of Science:

• Biomedical Engineering
• Rehabilitation Robotics
• Human-Computer Interaction

Background:

• Prosthetic controller design involves a trade-off between signal processing time and device responsiveness.
• Longer delays enhance electromyography (EMG) signal collection and classification accuracy.
• However, increased delays negatively impact the user's experience and prosthesis functionality.

Purpose of the Study:

• To determine the optimal controller delay for multifunctional prosthetic hands.
• To quantify the relationship between controller delay and prosthesis performance.
• To identify ideal delay ranges for different artificial hand speeds.

Main Methods:

• Twenty able-bodied subjects participated in the study.
• The Box and Block Test was utilized with a prosthetic hand system (PHABS).
• Controller delays varied across seven levels (0-300 ms) with two artificial hand speeds, analyzed using repeated measures ANOVA and linear mixed effects models.

Main Results:

• The optimal controller delay was identified as approximately 100 ms for fast prehensile movements and 125 ms for slower movements.
• A significant linear degradation in performance was observed with increasing controller delay.
• The findings highlight a clear performance impact based on delay duration.

Conclusions:

• The study provides specific optimal controller delay ranges for prosthetic hand users.
• Minimizing controller delay is crucial for maintaining prosthesis performance and user satisfaction.
• Future prosthetic designs should prioritize achieving delays within the identified optimal ranges for enhanced functionality.