A Lightweight Linear Actuating System for Finger Articulation: A Proof-of-Concept Study

Area of Science:

• Biomedical Engineering
• Robotics
• Rehabilitation Technology

Background:

• Existing hand orthoses often rely on complex mechanisms like rigid linkages or fluidic systems.
• There is a need for simpler, direct force transmission systems for finger articulation in assistive devices.

Purpose of the Study:

• To present a proof of concept for a novel actuating system for finger articulation.
• To evaluate the feasibility of using a linear actuator and spring steel strip for direct force transmission to the fingertip.
• To assess the system's capability for generating sufficient force and motion for hand grasping assistance.

Main Methods:

• Developed a direct-drive actuation system combining a linear actuator and a spring steel strip.
• Utilized a 3D-printed model finger to simulate a passive human finger.
• Tested the system's force generation by lifting various masses and analyzed motion profiles, joint angles, and actuator velocities.

Main Results:

• The actuating system demonstrated sufficient force generation and motion for grasping assistance.
• The system exhibited an adequate response time for practical application in hand orthoses.
• Component selection (linear actuators and steel strips) was optimized based on performance.

Conclusions:

• The proposed actuating system offers a promising alternative for hand orthosis design.
• The direct force transmission mechanism is effective for bidirectional finger articulation.
• Further development, including sensor integration, is planned for a functional orthosis prototype.