Thermal Actuated Bidirectional Gear

BY

CHRIS LANEY

SATYABH MISHRA

Introduction

� MEMS Bidirectional Gear are robust in nature.

It uses Thermal Actuation.� It uses Thermal Actuation.

� Large output Force, Stictionless Motion and Small Area.

� Reliable over a long period of time, in Millions of Cycles.

Design

� Specifications

� Bi-directionality Of Gear

� Achieved by thermal actuators

� 3 Thermal Actuators Used to Actuate and rotate the Gears.

� Performance

� Frequency ~300Hz

� Optimized using square wave DC signal

� The DC Signal can be controlled using a PWM IC or using a Simple Vpulse Signal with (Ton/Ttotal) as the Duty Cycle.

SANDIA AutoCAD Design

3D View

SANDIA AutoCAD Design

2D Cut Viewshowing Tunnel

SANDIA 3D Model

SANDIA 3D Model

SANDIA 3D Model

Tunnel View

ANSYS Design Test

� Maximum Displacement=22.154 Micro Meter

ANSYS Design Test

� Maximum Von Mises Stress of 4399

ANSYS Animation

Advantages

� The Gear can be rotated in Clock and Anti-Clockwise Direction.

� Very Low Stiction

� Improved Displacement

� It uses Thermal Actuation

� Large Life Cycle and High Temperature Range.

Point of Concern

� Hard to Design and Fabricate on Chip.

� Difficult to Align all the Chevron Actuators together.

� Gear is Connected with the help of bar. High Frequency Cooling and Heating can lead to Connection Error.

� Change in Direction : The Gear and Actuator needs to Cool Down , and move to their Original Shape and Position.

References

� Sandia Report : Compliant Thermo Mechanical MEMS Actuator LDRD #52553

� R. Cragun and L.L. Howell, “Linear Thermo mechanical Microactuators,”Microelctromechanical Systems (MEMS), at the 1999 ASME International Mechanical Engineering Congress and Exposition, ASME International Mechanical Engineering Congress and Exposition, pp. 181-188, November, 199

QUESTIONS?