Rapid moving by liquid-amplified electrostatic rolling.

Mobile robots that simultaneously have fast speeds, sufficient load-carrying capabilities, and multiple locomotive functions have always been challenging to develop. Here, we introduce a liquid-amplified electrostatic rolling (LAER) mechanism, which elegantly integrates actuation and adhesion into a streamline single-degree-of-freedom structure. Based on this, we developed a rigid tethered LAER roller (0.015 grams) that exhibited a rapid moving speed of ~210 body length per second on ceilings and a flexible tethered roller (10.600 grams) that had a load-to-weight ratio of ~121 moving on the ground. Liquid regulating modules were embedded into LAER structures to exhibit controlled moving. We also developed a single-wheeled and two-wheeled untethered LAER robots with onboard power supply. Furthermore, we demonstrate a LAER linear actuator and a camera equipped untethered LAER robot for preliminary environmental monitoring. The lightweight, scalable LAER structure is promising to bring fast electrostatic actuators, motors, and robots with superior load-to-weight ratios and multimodal locomotion capabilities such as turning, circular moving, and plane-to-plane transitioning.