Ultrahigh Agility with Trajectory Control of Insect-Scale Soft Robots

Agility and trajectory control are two desirable features for all moving objects but they become very challenging for soft robots without rigid structures to support rapid manipulations. Here, a curved piezoelectric thin film driven at its structural resonant frequency is utilized as the main body of an insect-scale soft robot for its fast translational movements, and two electrostatic foot-pads are employed for its swift rotational motions. These two schemes are simultaneously executed during operations via a simple two-wire connection arrangement. A highest relative centripetal acceleration of 28 body-length/s2 among all artificial robots is realized on a 65 mgtethered prototype, which is better than those of common insects, including the cockroach. The trajectory manipulation demonstration is accomplished by navigating the robot to pass through a 120 cm-long track in a maze within 5.6 seconds. One potential application is presented by carrying a 180 mg on-board sensor to record a gas concentration route map and to identify the location of the leakage source. The radically simplified analog motion adjustment technique enables the scale-up construction of a 240 mg-untethered robot. Equipped with a payload of 1660 mg to include the control circuit, a battery, and photoresistors, the untethered prototype can follow a designated, 27.9 cm-long “S” shape path in 36.9 seconds. These results validate key performance attributes in achieving both high mobility and agility to emulate living agile insects for the advancements of artificial soft robots.