Cui Yande,Hu Jianhua,Dong Ziyang,Li Bing,Chang Chunyu
Pneumatic artificial muscles have been widely used in the field of robotics because of their large output force and fast actuation, however, the accompanying bulky compressors and pumps limit their miniaturized applications. Despite current untethered pneumatic artificial muscles can be driven by adjusting the internal pressure, it is challenging to structurally mimic natural muscles with high water content. Here, we propose untethered pneumatic artificial muscles comprising a hydrogel actuator with snap-through instability and an air storage chamber. These hydrogel actuators can realize the conversion from hydrophobic association of octyl acrylate moieties to host-guest interaction between β -cyclodextrin and octyl acrylate under thermal stimuli, leading to the decrease of their moduli. The inflated hydrogel actuators exhibit rapid actuation with a radial expansion speed of 200% s −1 , which are powered by snap-through instability, thermal expansion of the gas inside the hydrogel actuator, and evaporation of water on its internal surface. With the pneumatic artificial muscles miniaturized, we demonstrate diving and rolling robots, exemplifying bionic robots able to adapt to and modify the environment. We expect that the design of hydrogel actuator in miniaturized pneumatic artificial muscles will facilitate rapid locomotion for future bionic robotic platforms.
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.