Ideal microrobots are on the millimeter-scale with integrated actuators, power sources, sensors, and controllers. Numerous researchers are inspired by insects for the mechanical or electrical design of microrobots. Previously, the authors proposed and demonstrated microrobots that can replicate the tripod gait locomotion of an ant, the legs of which were actuated by shape memory alloy (SMA) actuators. The SMA provided a large deformation and force, but the power consumed by actuating a single leg reached as high as 94 mW. This paper discusses a silicon electrostatic inchworm motor chip to move a robot leg with low energy consumption using a small power source. The inchworm motor chip was actuated by electrostatic motors. The power consumption was as low as 1.0 mW, in contrast with SMA actuators. The reciprocal motion of the inchworm motor chip is powered by silicon photovoltaic cells. The results show that the 7.5 mm 2 photovoltaic cells could produce 60 V to actuate the inchworm motor chip, and the generated force is enough to move the leg of the microrobot. Thus, we demonstrated the actuation of a microrobot leg using an electrostatic inchworm motor chip, which is the first reported instance of an electrostatic motor driving an off-chip structure.

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