Hybrid Soft-Rigid Elbow Exosuit: Theory, Mechatronic Design, and Experimental Assessment
Ali KhalilianMotamed Bonab, Cristian Camardella, Antonio Frisoli, and Domenico Chiaradia
AI summary
Problem
Current soft elbow exosuits suffer from hardware-induced inefficiencies like tendon friction, interface slippage, and compliance, which degrade control performance and necessitate impractical subject-specific tuning.
Approach
A theoretically guided hybrid mechatronic design featuring a compliant cuff, dual-cabling architecture, and passive cable tensioning, controlled by a generic fixed-parameter interaction controller.
Key results
- 28.40% reduction in biceps activity during dynamic tasks
- 44.55% reduction in infraspinatus activity during endurance tasks
- Mitigated muscle activation during load-carrying
- High usability and acceptance without subject-specific tuning
Why it matters
Demonstrates that robust mechatronic design enables reliable, plug-and-play upper limb assistance for clinical and occupational settings without complex individual calibration.
Abstract
Hybrid wearable robotics, combining soft and rigid elements, offer a promising solution for upper limb assistance by balancing comfort and functionality. This study evaluates a hybrid soft-rigid elbow exosuit designed for elbow movement support in dynamic and endurance tasks, focusing on biomechan- ical impact, user perception, and ergonomics. A theoretical model guided the design, optimizing device dynamics and assistive force delivery. A generic interaction controller, combined with fixed system parameters, provided effective assistance across partici- pants without the need for subject-specific tuning, simplifying deployment in practical settings. During dynamic tasks, the exosuit significantly reduced biceps muscle activity compared to the unassisted condition, with an average reduction of 28.40 %. In endurance tasks, it reduced infraspinatus activity by an average of 44.55 % and mitigated increased muscle activation during load-carrying. Subjective assessments indicated lower perceived physical demand, while the System Usability Scale confirmed high usability and acceptance. These findings highlight the exosuit’s ability to reduce physical effort and improve muscle coordination while maintaining comfort. The robust mechatronic design enabled effective assistance through a generic controller, emphasizing the importance of hardware reliability.