Encoding Smart Microjoints for Microcrawlers with Enhanced Locomotion

Usually, it is indispensable for traditional functional robots to use flexible joints that integrate sophisticated machinery and control systems to achieve precise operability and efficient mobility. At the microscale, however, the conventional design of functional joints is generally not suitable due to the limitation of the manufacturing process on such a tiny size. Herein, a strategy for the design of smart microjoints (SMJs) that undergo controllable active deformation by triggering a size-dependent layer-by-layer sequential swelling effect on SMJs in response to external stimuli is developed. The optimal encoding of SMJs that enables microcrawlers to achieve superior crawling speed (0.15 body lengths(-1)) and efficiency (1.1 body lengthper step), as well as controllable locomotion, is demonstrated, e.g., migration along/against the stimuli source or along a preplanned path. A path toward constructing soft actuators/robots at the microscale with high adaptability and controllability for broad engineering applications is offered.