Micro Ratcheting Transmission Systems Based on Electrostatic Actuator

This paper presents design and fabrication of a silicon micro ratcheting transmission system (RTS) that utilizes electrostatic comb-drive actuators to rotate a gear ring (or rotor) through a ratchet mechanism. The rotational actuator is engaged with the gear ring through ratchet teeth at one end, and reciprocally rotates around an elastic point at the other end based on electrostatic force. Rotational motion and torque from driving gear ring are transmitted smoothly to driven gears through involute profile gear teeth. Novelty design of anti-gap structures have overcome the unavoidable gap problem occurred in deep reactive ion etching of silicon. The micro RTS has been fabricated and tested successfully. The rotation of the motor is linearly proportional to driving frequency up to 40 Hz.