Sensors and Actuation Technologies in Exoskeletons: A Review

Exoskeletons are robots that closely interact with humans and that are increasingly used
for different purposes, such as rehabilitation, assistance in the activities of daily living (ADLs),
performance augmentation or as haptic devices. In the last few decades, the research activity on these
robots has grown exponentially, and sensors and actuation technologies are two fundamental research
themes for their development. In this review, an in-depth study of the works related to exoskeletons
and specifically to these two main aspects is carried out. A preliminary phase investigates the
temporal distribution of scientific publications to capture the interest in studying and developing
novel ideas, methods or solutions for exoskeleton design, actuation and sensors. The distribution
of the works is also analyzed with respect to the device purpose, body part to which the device is
dedicated, operation mode and design methods. Subsequently, actuation and sensing solutions for
the exoskeletons described by the studies in literature are analyzed in detail, highlighting the main
trends in their development and spread. The results are presented with a schematic approach, and
cross analyses among taxonomies are also proposed to emphasize emerging peculiarities.