Thermal Actuated Bidirectional Gear BY CHRIS LANEY SATYABH MISHRA
IntroductionMEMS Bidirectional Gear are robust in nature.It uses Thermal Actuation.Large output Force, Stictionless Motion and Small Area.Reliable over a long period of time, in Millions of Cycles.
DesignSpecifications Bi-directionality Of Gear Achieved by thermal actuators3 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 Design3D View
SANDIA AutoCAD Design 2D Cut Viewshowing Tunnel
SANDIA 3D Model
SANDIA 3D Model
SANDIA 3D ModelTunnel View
ANSYS Design TestMaximumDisplacement=22.154Micro Meter
ANSYS Design TestMaximumVon MisesStress of4399
AdvantagesThe Gear can be rotated in Clock and Anti-Clockwise Direction.Very Low StictionImproved DisplacementIt uses Thermal ActuationLarge Life Cycle and High Temperature Range.
Point of ConcernHard 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 andHeating can lead to Connection Error.Change in Direction : The Gear and Actuator needs to Cool Down , andmove to their Original Shape and Position.
ReferencesSandia Report : Compliant Thermo Mechanical MEMS Actuator LDRD#52553R. Cragun and L.L. Howell, “Linear Thermo mechanicalMicroactuators,”Microelctromechanical Systems (MEMS), at the 1999ASME International Mechanical Engineering Congress and Exposition,pp. 181-188, November, 199