Hand Rehabilitation Dynamic Splint with Variable Force via Pneumatic Artificial Muscle Actuators

Area of Science:

• Rehabilitation Engineering
• Biomedical Devices
• Soft Robotics

Background:

• Dynamic hand splints traditionally use passive elastic components for finger movement resistance.
• Controllable loads are desirable for real-time exercise adjustment and improved therapeutic results.
• Soft actuators offer potential advantages over elastic bands for dynamic hand splints.

Purpose of the Study:

• To develop and evaluate a dynamic hand splint utilizing soft pneumatic actuators as "inverse artificial muscles".
• To enable dynamically controllable loads for hand rehabilitation exercises.
• To assess the feasibility of using soft actuators for precise force modulation in hand splints.

Main Methods:

• A prototype dynamic splint was constructed using off-the-shelf materials and soft pneumatic actuators.
• Actuators were integrated into a forearm brace, connected to a finger via a tendon and an onboard load cell.
• The system underwent psychophysical testing to evaluate force perception and system accuracy.

Main Results:

• Psychophysical tests demonstrated reliable perception of force variations by subjects (sensitivity ~110%/bar).
• The system achieved accurate force control, with a minimum perceivable force of ~0.7 N at 3 bar in static tests.
• The maximum average force exerted was ~5.2 N at 0 bar.

Conclusions:

• The developed active splint, equipped with soft pneumatic actuators, shows promise for dynamic hand rehabilitation.
• This technology has the potential to significantly enhance the controllability and effectiveness of hand therapy.
• The findings support the use of soft actuators in creating advanced rehabilitation orthoses.