Bioinspired Origami Exosuit for Sequential Lifting Assistance with Energy-Aware Compliance and Event-Triggered Impedance

Abstract

Back injuries resulting from manual material handling have long constituted a prominent threat to occupational safety. While back-support exosuits offer the potential to augment human strength, their practical implementation is hindered by persistent challenges pertaining to comfort and safety. Drawing inspiration from human biomechanics and muscle behavior, we develop a lightweight assistive exosuit that synchronizes with natural load-handling rhythms. By integrating a deployable Kresling origami structure with a twostage transmission mechanism, a single motor can sequentially assist both the waist and arms, achieving motion-conforming support with minimal complexity. An energy-aware compliance control strategy allows the system to yield passively during unassisted motion, avoiding interference with voluntary human behavior. We propose an event-triggered impedance control strategy based on an energy tank framework, which adaptively intervenes only when interaction energy exceeds safety thresholds. Experimental results demonstrate substantial reductions in muscle activation during load-handling tasks, with decreases of up to 22.8%, 15.4%, and 14.8% in the biceps, triceps, and erector spinae (MVC%), respectively.