Fabric Pneumatic Artificial Muscle-Based Head-Neck Exosuit: Design, Modeling, and Evaluation

TL;DR

This paper presents a fabric pneumatic artificial muscle-based exosuit for head-neck support, including design, modeling, and evaluation, demonstrating its potential for assisting head-neck mobility with a focus on comfort and workspace limitations.

Contribution

The study introduces a novel soft exosuit design using fabric pneumatic muscles, with a physics-based model for actuator pressure and workspace analysis, advancing head-neck mobility assistance technology.

Findings

83% workspace coverage limited by actuator length

Gravity compensation reduces workspace to 43%

Exosuit effectively supports head movement in demonstrations

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 compensation 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.