Perspective on highly twisted artificial muscles

Lightweight and single-component artificial muscles represent a promising alternative to conventional actuators for several applications requiring a large power/weight ratio, including modern soft and assistive robotics. Highly Twisted Artificial Muscles (HTAMs) are a relatively young category of artificial muscles, introduced only in 2011. Considering their young age, there is still a lack of awareness in the scientific community on what has been accomplished so far in this field and what are current challenges and limitations. This Perspective paper aims to provide an extensive overview in terms of working mechanism, manufacturing, modeling, and applications of different types of HTAMs. A discussion on challenges and future directions is then provided to encourage transformative research on this topic.