The use of soft materials in robot development has emerged as a way to increase the adaptability of robots and their safe interaction with humans. Although soft robots will likely never achieve the precision of the more traditional ‘rigid’ robots, their inherent adaptivity pushes state-of-the-art developments towards new medical applications such as rehabilitation and diagnostic devices, exoskeletons for gait assistance, and in vivo assist devices. However, despite exciting developments, there are still major challenges in the development of soft robots. In particular, existing electronic control, intelligence and power of soft robots is too bulky to be embedded, and the power efficiency of soft robots is extremely low.