Study on silicon device of microrobot system for heterogeneous integration

The ideal microrobots are millimeter sized with integrated actuators, power sources, sensors, and controllers. Many researchers take the inspiration from insects for the mechanical or electrical designs to construct small sized robotic systems. Previously, the authors proposed and demonstrated microrobots which can replicate the tripod gait locomotion of an ant and the legs were actuated by shape memory alloy actuators. Shape memory alloy provided a large deformation and a large force, but the power consumption was as high as 94 mW to actuate a single leg. This paper discusses the silicon electrostatic inchworm motor chip with low energy consumption for the robot leg by using a small-size power source. The inchworm motor chip has actuated by electrostatic motors. The power consumption is low as 1.0 mW compering with shape memory alloy actuators. The reciprocal motion of the inchworm motor chip is power by the silicon photovoltaic cells. Results show the 7.5 mm square size photovoltaic cells could produce 60 V to actuate the inchworm motor chip. The generated force is enough to move the leg of the microrobot. We have shown actuation of the microrobot leg using an electrostatic inchworm motor chip. This result is the first instance of an electrostatic motor driving an off-chip structure.