A novel electric stimulus-responsive micro-actuator for powerful biomimetic motions

Limited by the surface-to-volume ratio of structural materials, it is a great challenge to achieve high output performance in a millimetre-sized actuator. Traditional rigid actuators can achieve higher vibration frequencies above the centimetre size, but their working performance will be greatly reduced below the millimetre size, and even cannot maintain the vibration. A micro-actuator is highly essential for the miniaturisation of bionic robots. In this work, we present a novel driving principle by utilising the plasmonic thermal energy generated by electric stimulation to drive the vibration of the micro-actuator. In the design, the micro-actuator is composed of two chambers and elastic elements, which is similar to the design of a micro-piston. By utilising the thermal energy of the plasma, the actuator can generate high-frequency vibration (resonant frequency of 140 Hz), and the simple structural design can achieve a large vibration amplitude on a millimetre scale. Based on this powerful actuator, several applications are presented, such as fast crawling and jumping. The good performance of the electric stimulus-responsive micro-actuator suggests promising applications ranging from millimetre-scale robots in confined spaces to detection, search and rescue.