An ecologically-controlled exoskeleton can improve balance recovery after slippage

TLDR

Human bipedal evolution required dynamic balance strategies, but aging and lower‑limb loss impair stability and increase fall risk. The study aims to develop a novel solution that counteracts balance loss and prevents falls in older and fragile individuals. The Active Pelvis Orthosis detects balance loss and delivers hip torques to assist recovery. Tests on eight elderly and two transfemoral amputees showed that the APO’s on‑demand hip torque assistance improved stability, required minimal personalization, and indicates promise for real‑world use.

Abstract

The evolution to bipedalism forced humans to develop suitable strategies for dynamically controlling their balance, ensuring stability, and preventing falling. The natural aging process and traumatic events such as lower-limb loss can alter the human ability to control stability significantly increasing the risk of fall and reducing the overall autonomy. Accordingly, there is an urgent need, from both end-users and society, for novel solutions that can counteract the lack of balance, thus preventing falls among older and fragile citizens. In this study, we show a novel ecological approach relying on a wearable robotic device (the Active Pelvis Orthosis, APO) aimed at facilitating balance recovery after unexpected slippages. Specifically, if the APO detects signs of balance loss, then it supplies counteracting torques at the hips to assist balance recovery. Experimental tests conducted on eight elderly persons and two transfemoral amputees revealed that stability against falls improved due to the "assisting when needed" behavior of the APO. Interestingly, our approach required a very limited personalization for each subject, and this makes it promising for real-life applications. Our findings demonstrate the potential of closed-loop controlled wearable robots to assist elderly and disabled subjects and to improve their quality of life.