design of origami-based actuators* -...
TRANSCRIPT
1UW - Center for Intelligent Materials and Systems
Design of Origami-based Actuators*
Minoru Taya, DirectorCenter for Intelligent Materials and Systems
Nabtesco Endowed Chair ProfessorUniversity of Washington Email: [email protected]
http://depts.washington.edu/cims/Collaborators: Profs. Miura, Tachi, University of Tokyo
* This work was supported by a AFOSR grant and Nabtescocontract to University of Washington
November 26, 2013
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Contents of my talk
• 1. Tachi-Miura Bellow under compressive force
• 2. Bellow actuator based on FSMA composite
• 3. Bioinspired design of SMA actuator for beetle wing folding/unfolding
• 4. free-falling MAV made of origami
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1. IntroductionGoal: Applying “Origami” to engineering application such as actuators and developable space structures
Rigid-foldable structures‒ Deformation takes place only along the crease lines
zyx
Tachi-Miura Polyhedron
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Compression loading
4
H0
xy
z
FCompression Test
Conditions for compression test of TMP bellow
Initial heightH0 [mm]
Total displacement[mm]
Displacement rate[mm/sec]
150 100 2.0
Folding Behavior of TMP (Proc. Roy. Lond. 2013, A469,20130351)
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Result(2) Considering Thickness of the paper(Single layer)
(2) Considering Thickness of the paper(Single layer)
3. Folding Behavior of TMPComparison between experiment and prediction
Extended Hamilton Principle (Taya and Mura, 1974) 1 1
0 0
t t
t tJ T U dt Ddt
2
0 0
1 22
f f
i i
t t
d i iV l S lJ v dV M dl F udS dt Ddl dt
2i
il sB M dl F du
Negligibledue to compression speed
Kinetic Energy BendingWork
MechanicalWork
Energy Dissipation
Apply the prediction force
Compression Test of TMP
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Result
6
(2) Considering Thickness of the paper(Single layer)
(2) Considering Thickness of the paper(Single layer)
3. Folding Behavior of TMPComparison between experiment and prediction
Mechanical WorkW [J]
Bending Work B [J]
δJ[J]
δJ/W[%]
0.338 0.292 0.046 13.6
Result of compression test
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Where are the energy dissipations ?
• 1. plastic work at the high stress concentration points; vertices and crease lines
• 2. friction work of the top and bottom surfaces over the fixed boundary
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Result
8
(2) Considering Thickness of the paper(Single layer)
(2) Considering Thickness of the paper(Single layer)
3. Folding Behavior of TMPComparison between experiment and prediction
Mechanical WorkW [J]
Bending Work B [J]
δJ[J]
δJ/W[%]
0.285 0.254 0.031 10.9
Result of compression test
TMP without vertices
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Result
9
(2) Considering Thickness of the paper(Single layer)
(2) Considering Thickness of the paper(Single layer)
3. Folding Behavior of TMPEnergy Dissipation
1) Friction at the top and bottom
Cro
ss-s
ectio
n ar
ea [m
m2 ]
Displacement u [mm]0 20 40 60 80
4250
4200
4150
4100
4050
4000
3950100
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Concept A: Hybrid Mechanism of FSMA and FSMA composites
im
itij,j vρfσ
ijpj
mi HMf ,0
Chain-reaction: Applied magnetic field gradient
magnetic force Stress-induced martensite transformation low stiffness of FePd large deformation
0
40
80
120
0 50 100 150
Temperature (°C)
Youn
g’s m
odul
us(G
Pa)
Ms-50
martensite phase
austenite phase
austenite phase
Stress ()
Temperature(T)
martensite phase
Alm
ost p
aral
lel
The effect of uniform (constant) magnetic field is very small
3D-phase diagram
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Early bellow design
N H
d
D
t
Rθ
• Parametric study on this bellow using FEA has been done to optimize the design to reduce the reaction force.
• However, it was found that this shape is not suitable to reduce the reaction force because of its circumferential stress.
• Moreover, this shape is not easy to manufacture.
Compressive force
Circumferential stress
Switched to new design
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Segmented type bellow actuator
NiTi curved plate
Rigid part
Bolt & Nut
A A
Section A-A
EM driverSMA Leg
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Bending fatigue curve
Pulsating 4-point bendingNominal thickness: 0.7 mm, Frequency: 10 Hz, Temperature: 25 °C, in air
• Fatigue life of chemically etched specimen is slightly longer.• Fatigue limit is around proportional limit strain (εpr).
εpr = 0.5 %
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Wing folding and unfolding of a beetle (Allomyrina Dichotoma)
During the time on the ground the beetles store their hind wings under a thick forewing (Elytron) from damages.
When the beetle is about to fly, it open's the thick fore wing and forcefully opens the hind wing to straighten the wing.
(Nomura, 2010)
Unfolding of hindwing
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Past Study-1 on origami folding(Haas, 1996)
The complex wing of the beetle is a combination of several basic vertex mechanism.
At every vertex where 4 lines converge 3 mountain folds to 1 valley fold or 3 valley fold to 1 mountain fold is formed.
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Conclusion
Ratio Comparison
Real Beetle Wing
bio-inspired Wing
2.32 3.141
Surface Area of Unfolded WingSurface Area of Folded Wing Folding Ratio =
Beetle Wing
Bio-inspired Wing
Folded Unfolded
Best ratio degreesAlpha degree Beta degree Ratio
14° 85° 3.14
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Hitching methods
(Richard and Davies, 1977)
ThoraxWing Folding(heated)
Heated
Room Temperature
Wing folded(heating stopped)
Opening for hook
Bio-inspired hitching method
Nature Design: Insect wing hitching method
Fore Wing
Hind Wing
Hitching claw
Hitching claw
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Bio-inspired Wing Storage
Wings folded completely in the Thorax by the SMP, SMA and remain folded by the hook.
Wings expanded by the SE in room temperature
When heated the wing will fold into it's memorized shape and
unfold to it's flat state in room temperature.
Thorax
SMA Hook
Opening for hook
Wing Hitched
room temperature
50% heating
80%heating
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Folding of leaves(Kentucky Blue Grass)
Fig. 2. How a leaf of Kentucky bluegrass Poa pratense (a European weed) can fold to exhibit large morphing using the concept of expansion and shrinkage of motor cells, (a) zoom up of the upper part of the leaf with expanded motor cells, (b)-(e) sequence of expansion, entire leaf showing folded in morphology by kinking at several hinges.
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Expansion of Super-configurable MAV