Fabric Pneumatic Artificial Muscle-Based Head-Neck Exosuit: Design, Evaluation, and Modeling
Katalin Schäffer, Ian Bales, Haohan Zhang, Margaret McGuinness
AI summary
Problem
Rigid-link neck exoskeletons are bulky and restrictive, while existing cable-driven soft alternatives suffer from friction, compliance, and routing limitations, creating a need for a lighter, more compliant wearable device to assist head-neck mobility in neurological patients.
Approach
The team designed a seven-actuator fabric pneumatic artificial muscle (fPAM) exosuit prototype and developed a physics-based static model to calculate actuator pressures for gravity compensation, evaluating workspace coverage, range of motion, and neck compression forces through simulation and physical testing.
Key results
- Modeled workspace coverage reaches 83% with actuator limits and drops to 43% under gravity compensation constraints.
- Compression force along the neck introduced as a novel comfort metric, with thresholds significantly impacting feasible workspace.
- Optimized actuator placement strategy validated for lateral stability and high axial rotation torque.
- Test dummy and human demonstrations confirm functional head support and trajectory tracking.
Why it matters
Provides a viable, lightweight soft-actuation alternative to bulky rigid exoskeletons for patients with dropped head syndrome and other neurological mobility impairments.
Abstract
Wearable exosuits assist human movement in tasks ranging from rehabilitation to daily activities; specifically, head- neck support is necessary for patients with certain neurological disorders. Rigid-link exoskeletons have shown to enable head- neck mobility compared to static braces, but their bulkiness and restrictive structure inspire designs using “soft” actuation methods. In this paper, we propose a fabric pneumatic artificial muscle-based exosuit design for head-neck support. We describe the design of our prototype and physics-based model, enabling us to derive actuator pressures required to compensate for gravitational load. Our modeled range of motion and workspace analysis indicate that the limited actuator lengths impose slight limitations (83% workspace coverage), and gravity compen- sation imposes a more significant limitation (43% workspace coverage). We introduce compression force along the neck as a novel, potentially comfort-related metric. We further apply our model to compare the torque output of various actuator placement configurations, allowing us to select a design with stability in lateral deviation and high axial rotation torques. The model correctly predicts trends in measured data where wrapping the actuators around the neck is not a significant factor. Our test dummy and human user demonstration confirm that the exosuit can provide functional head support and trajectory tracking, underscoring the potential of artificial muscle–based soft actuation for head–neck mobility assistance.