A versatile knee exoskeleton mitigates quadriceps fatigue in lifting, lowering, and carrying tasks
Open accessAbstract
The quadriceps are particularly susceptible to fatigue during repetitive lifting, lowering, and carrying (LLC), affecting worker performance, posture, and ultimately lower-back injury risk. Although robotic exoskeletons have been developed and optimized for specific use cases like lifting-lowering, their controllers lack the versatility or customizability to target critical muscles across many fatiguing tasks. Here, we present a task-adaptive knee exoskeleton controller that automatically modulates virtual springs, dampers, and gravity and inertia compensation to assist squatting, level walking, and ramp and stairs ascent/descent. Unlike end-to-end neural networks, the controller is composed of predictable, bounded components with interpretable parameters that are amenable to data-driven optimization for biomimetic assistance and subsequent application-specific tuning, for example, maximizing quadriceps assistance over multiterrain LLC. When deployed on a backdrivable knee exoskeleton, the assistance torques holistically reduced quadriceps effort across multiterrain LLC tasks (significantly except for level walking) in 10 human users without user-specific calibration. The exoskeleton also significantly improved fatigue-induced deficits in time-based performance and posture during repetitive lifting-lowering. Last, the system facilitated seamless task transitions and garnered a high effectiveness rating postfatigue over a multiterrain circuit. These findings indicate that this versatile control framework can target critical muscles across multiple tasks, specifically mitigating quadriceps fatigue and its deleterious effects.
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- Authors
- Divekar, N. V., Thomas, G. C., Yerva, A. R., Frame, H. B., & Gregg, R. D.
- Affiliations
- University of Michigan (US)
- Corresponding author
- Divekar, Nikhil V.
- Gregg, Robert D.
- Venue
- Science Robotics
- Published
- 2024-09-18
- Volume
- 9
- Issue
- 94
- Pages
- eadr8282-eadr8282
- ISSN
- 2470-9476 (ISSN-L)
- PMC
- PMC11507003
- OpenAlex
- W4402592523
- Cited by
- 52
- References
- 68
- Citations by year
- 2026: 24 · 2025: 27 · 2024: 1
- FWCI
- 5.69
- Type
- journal article
- Language
- en
- Open access
- green
- pmc.ncbi.nlm.nih.gov
- Locations
- Science Robotics (publishedVersion)
- PubMed (publishedVersion)
- PubMed Central (publishedVersion)
- Europe PMC (PubMed Central) (acceptedVersion)
- Funders
- National Institutes of Health
- National Institute of Biomedical Imaging and Bioengineering (R01EB031166)
- Topics
- Physical Sciences › Engineering › Biomedical Engineering › Prosthetics and Rehabilitation Robotics
- Physical Sciences › Engineering › Biomedical Engineering › Muscle activation and electromyography studies
- Physical Sciences › Engineering › Biomedical Engineering › Soft Robotics and Applications
- Keywords
- knee exoskeleton, quadriceps fatigue, stair ascent and descent, repetitive lifting
- MeSH terms
- Exoskeleton Device, Adult, Biomechanical Phenomena, Equipment Design, Female, Humans, Knee, Knee Joint, Male, Posture, Robotics, Task Performance and Analysis, Walking, Lifting, Muscle Fatigue, Torque, Quadriceps Muscle, Young Adult
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