Design and Evaluation of a Compact Elbow Exoskeleton with Gravity Compensation for Upper-Limb Assistance

Abstract

This thesis presents the design, development, and preliminary evaluation of a lightweight elbow exoskeleton intended to reduce upper-limb fatigue during sustained and repetitive tasks. Upper-limb fatigue is a common challenge in both occupational and rehabilitative settings, often leading to decreased performance and increased risk of injury. Existing assistive devices frequently face tradeoffs between functionality, weight, and wearability, motivating the need for simpler and more accessible solutions. The proposed system employs a compact, direct-drive actuation approach to provide assistive torque at the elbow joint while maintaining a low-profile and portable form factor. The mechanical and electrical design processes are detailed, including considerations for ergonomics, torque requirements, and ease of use. A control strategy for gravity compensation is implemented to support the user during static and dynamic arm movements. Preliminary testing was conducted with human subjects to assess the device’s ability to reduce perceived effort during a static holding task. Results indicate qualitative reductions in user-reported fatigue and demonstrate the feasibility of the design. Overall, this work contributes (1) the design of a simple, wearable elbow exoskeleton with direct-drive actuation, (2) an implementation of a gravity-compensation control approach for fatigue reduction, and (3) initial experimental observations supporting its potential effectiveness. Future work will focus on expanded user studies, improved control strategies, and optimization of torque output and device ergonomics.