Untethered soft microrobot driven by a single actuator for agile navigations.

Cockroaches are renowned for their ability to swiftly navigate through tight spaces and robustly withstand high impacts due to their well-controlled locomotion and highly flexible exoskeletons. It has been a long-standing challenge to replicate these features in untethered controllable microrobots (weighing~1 g). Here, we show that a single actuator is used to tune a microrobot's leg strokes for controllable movements in various directions (forward, backward, and diagonal). Weighing just over 1 g and measuring 2 cm in length, the untethered microrobot achieves a forward speed of 4.8 body lengths per second (BL/s) and a turning speed of 280 deg/s, resulting in an outstanding maneuverability that has only previously been achieved in multiply-actuated microrobots. The untethered microrobot can remain functional after being stepped on. The single actuator driving scheme, device structural architecture, and control techniques are investigated as key guidance for the development of future controllable and resilient miniaturized robots.