Novelmicro Transportation Systems Based on Ratchetmechanism and Electrostatic Actuators

This paper describes a design and fabrication of Si micro transportation systems (MTS) to drive microcars based on ratchet mechanism and electrostatic comb-drive actuators. This MTS consists of linear and rotational comb actuators, microcars, and micro ratchet mechanism. The microcars can be moved with different velocities by comb-drive actuators through ratchet teeth. In this study, the MTS was fabricated by using SOI wafer with device layer of 30 mum, buried SiO₂ layer of 4 mum, and with only one mask. In our experiments, the movement of the microcar has been tested with driving frequency ranges from 5 Hz to 40 Hz. The velocity of the microcar was proportional to the driving frequency, and it matched well with theoretical calculation.