A Centimeter-Scale Electrohydrodynamic Multi-Modal Robot Capable of Rolling, Hopping, and Taking Off

Insects and animals in nature generally have various modes of locomotion to adapt to complex environments, such as crawling, running, flying, and jumping. Achieving multi-locomotion in a centimeter-scale robot requires complex structures and mechanisms that are normally difficult to design and fabricate. In this article, we propose a centimeter-scale robot powered by electrohydrodynamic propulsion capable of rolling, hopping, and taking off. The robot's mass, body length, and height are 203 mg, 6.5 cm, and 4.1 cm, respectively. The robot has a simple mechanical structure, consisting of electrohydrodynamic thrusters, wheels, and supporting beams. By only controlling the magnitude of the thrust, the proposed robot can roll, hop, and take off. The experimental results show that this robot's rolling speed reaches 72.1 cm/s (11.1 body length/s). The takeoff of the robot along a vertical guide and the hopping performance over various obstacles are also demonstrated. This study extends the potential for applying electrohydrodynamic propulsion to centimeter-scale robots.