04/20/23 ME Senior Design Spring 2008 1

Bi-Directional Rotary Bi-Directional Rotary ActuatorActuator

Group 9Group 9

Sung BaeSung Bae

Robert Hooge Robert Hooge

Chris ImparatoChris Imparato

Jose JaramilloJose Jaramillo

04/20/23 ME Senior Design Spring 2008 2

What is a Rotary Actuator?What is a Rotary Actuator?

N S S N

N S S N

N S S N

360 deg

Non-energized

N

N S S N

N S S N

N S S N

N N

S S S

N S S N

N S S N

N S S N

S S S

N N N

Energized - polarity30 deg CW rotation

Energized + polarity30 deg CCW rotation

Upper stator

Rotor

Lower stator

N S S N

N S S N

N S S N

- or +

Sandia coil design: Coil is constrained to one side of actuator. Magnetic field conducts thru can to opposite stator.

04/20/23 ME Senior Design Spring 2008 3

Needs AssessmentNeeds Assessment

Replace two uni-directional solenoids with Replace two uni-directional solenoids with single bi-directional solenoid. single bi-directional solenoid.

Used in weapon components systemsUsed in weapon components systems Should be adaptable to Micro-Electro-Should be adaptable to Micro-Electro-

Mechanical System (MEMS) for Mechanical System (MEMS) for miniaturization.miniaturization.

04/20/23 ME Senior Design Spring 2008 4

ScopeScope

Design a bi-directional rotary actuatorDesign a bi-directional rotary actuator• Compact and easy to assembleCompact and easy to assemble

• Rotates either clockwise or counterclockwise with a return Rotates either clockwise or counterclockwise with a return to a neutral positionto a neutral position

• Electro-magnetic with a permanent magnet rotorElectro-magnetic with a permanent magnet rotor

• Takes full advantage of maximum moment arm availability Takes full advantage of maximum moment arm availability (pancake style)(pancake style)

• Single coil designSingle coil design

• Directionality is controlled by coil polarityDirectionality is controlled by coil polarity

04/20/23 ME Senior Design Spring 2008 5

Constraints/GoalsConstraints/Goals

Rotor must be 2” in diameterRotor must be 2” in diameter No springs to return to neutral positionNo springs to return to neutral position Torque must be 0.31Nm or greaterTorque must be 0.31Nm or greater Step size of 20° - 30°Step size of 20° - 30°

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Original DesignsOriginal Designs

04/20/23 ME Senior Design Spring 2008 7

Major changesMajor changes Cylindrical housingCylindrical housing

• Uniformly distributed magnetic fieldUniformly distributed magnetic field Inner magnets used.Inner magnets used.

• Helped to increase torque. Helped to increase torque. Changed from 4 poles to 3Changed from 4 poles to 3 Taller coilTaller coil

• Lowered current density Lowered current density • Distributed temperature over larger area.Distributed temperature over larger area.

04/20/23 ME Senior Design Spring 2008 8

Final DesignFinal Design

Magnets left out for clarity

NS

04/20/23 ME Senior Design Spring 2008 9

Exploded ViewExploded View

1-64 Flat Head Screws

Outer Housing

Snap Ring

Shaft

Upper StatorBase Plate

Lower Stator

Shoulder BearingCoil CoreCoil

Rotor Bushing

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2-D Simulation2-D SimulationUsing Maxwell 2-D SV

Off Position (No Current)

04/20/23 ME Senior Design Spring 2008 11

2-D Simulation2-D SimulationOn Position (1500A)

Shading in above figure represents magnetic field, lines represent magnetic flux

04/20/23 ME Senior Design Spring 2008 12

3-D Simulation3-D Simulation

De-Energized EnergizedUsing Maxwell 3-D

04/20/23 ME Senior Design Spring 2008 13

Thermal ModelingThermal Modeling

Surface TemperatureSurface Temperature• Surrounding objectsSurrounding objects• SafetySafety• Determined materials Determined materials

used for coilused for coil

E-PhysicsE-Physics

Calculated - 72°C Max

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CalculationsCalculations

Calculations from Assumed Values Calculations from Measured Values

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Fabricated PartsFabricated PartsBase Plate Coil Core

Lower StatorHousing

Upper Stator

Coil & Spool

Rotor&

Shaft

Winding Device

Screws

04/20/23 ME Senior Design Spring 2008 16

AssemblyAssembly

Coil and Lower Stator Assembly Rotor Assembly

Assembly Full Assembly

04/20/23 ME Senior Design Spring 2008 17

Assembly ProblemsAssembly Problems

Tolerances on shaft and rotorTolerances on shaft and rotor• Remade rotor and shaftRemade rotor and shaft• Made shoulder on shaftMade shoulder on shaft

Used bushing in upper statorUsed bushing in upper stator• Press fitting 2 bearings posed disassembly Press fitting 2 bearings posed disassembly

problemsproblems

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Operational SetupOperational Setup

04/20/23 ME Senior Design Spring 2008 19

OperationOperation

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Torque TestTorque Test

Using Torque Gauge

Generated - .068 N-m

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Thermal TestsThermal Tests

Temperature after 2 minutes Temperature after 5 minutes

47.4° C 53.2° C

04/20/23 ME Senior Design Spring 2008 22

ConclusionsConclusions

Proof of concept Proof of concept • Single bi-directional solenoidSingle bi-directional solenoid

TorqueTorque• .068 N-m 1/5 Predicted value.068 N-m 1/5 Predicted value• 22ndnd Test TBD Test TBD

Measure stall torqueMeasure stall torque

Step SizeStep Size• 10°-15°10°-15°

04/20/23 ME Senior Design Spring 2008 23

RecommendationsRecommendations

Housing with 3 walls aligned with stators.Housing with 3 walls aligned with stators. Magnet spacing.Magnet spacing. Stators: wider with larger radius than Stators: wider with larger radius than

magnets.magnets.

Diagrams to be inserted

04/20/23 ME Senior Design Spring 2008 24

AcknowledgmentsAcknowledgments

Sponsor - Gilbert Benavides (SNL)Sponsor - Gilbert Benavides (SNL) Advisors Advisors

• Dr. MassonDr. Masson• Dr. EnglanderDr. Englander

NHMFLNHMFL• Lee MarksLee Marks

Graduate Machine Shop StaffGraduate Machine Shop Staff Dr. LuongoDr. Luongo

04/20/23 ME Senior Design Spring 2008 25

Questions?Questions?