Smart suits like those worn by the fictional Iron Man are closer to becoming a reality than we think. Smart, textile-based soft robotic exosuits are soon going to be a great tool that helps firefighters, soldiers and rescue workers navigate difficult terrain. Exosuits could also enhance mobility and quality of life for the elderly and people with neurodegenerative disorders.
The multi-joint soft exosuit consists of textile apparel components worn at the waist, thighs and calves that guide mechanical forces from an optimized mobile actuation system attached to a rucksack via cables to the ankle and hip joints. Source: Wyss Institute at Harvard University
A team from the Wyss Institute for Biologically Inspired Engineering and the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS), led by Conor Walsh, have been developing soft, wearable robotic devices that can support mobility, including exosuits. The new exosuits have mechanical forces placed at the critical joints on the body, like the waist or knees.
Lab versions of the soft robotic exosuits have demonstrated benefits for all kinds of walking needs. The suit allows the wearer to spend less energy when walking and running, which is a boon for emergency responders and people who struggle to walk.
The team has presented the latest generation of a mobile multi-joint exosuit at 2018 IEEE International Conference on Robotics and Automation. This suit helped researchers develop an automatic tuning method that can customize the assistance that the suit provides the user based on how the wearer’s body is responding to the suit.
The multi-joint exosuit is made of textile apparel and is worn at the waist, thighs and calves. The optimized mobile actuation system is at the waist section of the suit and is integrated into a military rucksack. Mechanical forces are transmitted through cables that are guided throughout the exosuit to the ankle and hip joints.
"We have updated all components in this new version of the multi-joint soft exosuit: the apparel is more user-friendly, easy to put on and accommodating to different body shapes; the actuation is more robust, lighter, quieter and smaller; and the control system allows us to apply forces to hips and ankles more robustly and consistently," said David Perry, a co-author of the ICRA study and a staff engineer on Walsh's team.
The suit was tested by soldiers on a 12-mile, cross-country course.
"We previously demonstrated that it is possible to use online optimization methods that by quantifying energy savings in the lab automatically individualize control parameters across different wearers. However, we needed a means to tune control parameters quickly and efficiently to the different gaits of soldiers at the Army outside a laboratory," said Walsh, Ph.D., core faculty member of the Wyss Institute, the John L. Loeb Associate Professor of Engineering and Applied Sciences at SEAS and founder of the Harvard Biodesign Lab.
The team's new tuning method uses the exosuit’s sensors to optimize the positive power delivered to the ankle joints. The system then measures the user’s power and gradually adjusts the controller parameters until it finds just the right levels. This method could also be used as a proxy measure for elaborate energy movements.
"We evaluated the metabolic parameters in the seven study participants wearing exosuits that underwent the tuning process and found that the method reduced the metabolic cost of walking by about 14.8% compared to walking without the device and by about 22% compared to walking with the device unpowered," said Sangjun Lee, the first author of both studies and a graduate student with Walsh at SEAS.
"This research marks an important point in the Wyss Institute's Bioinspired Soft Robotics Initiative and its development of soft exosuits in that it opens a path on which robotic devices could be adopted and personalized in real world scenarios by healthy and disabled wearers," said Wyss Institute founding director Donald Ingber, M.D., Ph.D.
The paper on exosuits was published in the Journal of NeuroEngineering and Rehabilitation (JNER).
