Self-regulating shape memory alloy robots controlled with ...
Transcript of Self-regulating shape memory alloy robots controlled with ...
2020. 06. 29
Current status of Structural Materials
Hyun Wook Na & Ji Young Kim
Self-regulating shape memory alloy robots
controlled with soft ionic skin strain sensor
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Contents
Proposal of Self-regulating SMA strain sensor
Material selection & cyclic training for two-way SME
Two-way SMA as electrode of capacitive ionic sensor
Fabrication of Capacitive ionic sensor
Adhesion of SMA and hydrogel
Demonstration of Capacitive ionic sensor operation
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Proposal of Self-regulating soft robot
Joule heating
Two-way SME(High T shape)
Strain sensing
Voltage control
Two-way SME (Low T shape)
Strain sensing
Voltage control
Scheme of self-regulating shape memory alloy robots with ionic skin
Fast and strong reversible actuation controlled by joule heating with simple system
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Motivation of developing self-regulating sensor
Limitation of Low actuation stress, Low actuation frequency
Ionic hydrogel gripper
Zheng, J., et al. (2018). "Mimosa inspired bilayer hydrogel actuator functioning in multi-environments." Journal of Materials Chemistry C 6(6): 1320-1327.
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Motivation of developing self-regulating sensor
Limitation of Complex control system for high actuation frequency and stress
Rothermund et al, Bistable valve for autonomous control of soft actuators, Science Robotics (2018) p.7986
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Motivation of developing self-regulating sensor
Motivation of this study
Temperature sensitive shape change
Rapid response to the situation (Temp.)
Structural materials
Two-way SMA
Capacitive strain sensorSandwich structure of
Electrode / Dielectric layer / ionic hydrogel
Electrode metal – ionic hydrogel layer structure
Electrode
Ionic Hydrogel
Dielectric layer
Sensitive sensing system
Skin-like soft compliance
Simple layer structure
Capacitive ionic sensor
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Two-way Shape memory alloys
Two-way SMA
https://www.youtube.com/watch?v=xhykVMFDULk
J Ma, I Karaman & R.D. Noebe, Internatinal Materials Reviews 55 (2010)
https://en.wikipedia.org/wiki/Shape-memory_alloy
Various Application as temperature sensitive sensor / grabber
Stress
Heat
Cool
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Two-way Shape memory alloys
J Ma, I Karaman & R.D. Noebe, Internatinal Materials Reviews 55 (2010)
https://en.wikipedia.org/wiki/Shape-memory_alloy
Thermally-induced martensite(Various variants, Twinned M)
Stress-induced martensite(Single variant, Detwinned M)
ㅡMacroscopic shape, size
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Material selection for Two-way SMA as Capacitive sensor
Condition : Low T (Room temperature) ↔ High T (Joule heating)
S.Y. Yang et al., Journal of Alloys and Compounds 490 (2010) L28-L32
B . Stranadel et al., Materials Science and Engineering A 202 (1995) 148-156
electric power input : 12.09 W
1.338V, 9.04A
(Resistance SMA wire : 4.933Ω/m)
“Temperature gradient from 504K to 413K
is developed by the Joule heating”
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30 40 50 60 70 80-25
-20
-15
-10
-5
0
5
10
15
20
25
Heating →
← Cooling MS = 55oCMf = 40oC
Af = 70oCAs = 57oC
← E
xoth
erm
ic (W
/g)
Temperature ( oC )
Phase transformation temperature of Ti50Ni40Cu10
DSC analysis (10K/min)
To reach the phase transformation temperature via joule heating
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Thermomechanical Cyclic training
Select A2 cyclic training method among 4 different method (100 Cycle)
Diverse cyclic training method to apply two-way SME
Y. LIU et al., Acta metall. Mater. 38 (1990) 1321-1326.
“Training is a procedure to develop dislocation arrangements
which guide the formation of martensite variants of a preferred orientation”
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Cyclic training | Two-way Shape memory effect
High T (T > Af) Low T (T < Mf)
100 cycle
w/o stress
with stress
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T > Af T < Mf
Cyclic training | Two-way Shape memory effect
After 100 cycle
1. To improve change of curvature
Thickness reduction (Cold-Rolling & Heat-treatment)
2. To improve resistance for joule heating Width reduction
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Cyclic training | Two-way Shape memory effect
We improved curvature difference by reducing the thickness of specimen.
Thickness : 1.1 mm → 0.8mm (27% cold-rolled)
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Two-way Shape memory effect via Joule heating
Heating Cooling
Movie (x4)
We confirmed the two-way shape memory effect via joule heating.
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When uniaxial force stretches dielectric 𝝀𝝀 times,
both the width and the thickness of the dielectric reduce by a factor of 𝝀𝝀,
and the capacitance of the dielectric scales as 𝑪𝑪 = 𝑪𝑪𝟎𝟎𝝀𝝀
Fabrication of Capacitive ionic sensor
Shape Memory Alloy
Ionic hydrogelDielectric layer (3M VHB)
= Rigid Backbone + Electrode + Fast actuator
= Soft cover + Sensor
V
1𝐶𝐶 =
2𝐶𝐶𝐸𝐸𝐸𝐸𝐸𝐸
+1𝐶𝐶𝐸𝐸
𝐶𝐶𝐸𝐸𝐸𝐸𝐸𝐸/𝐶𝐶 ≈ 105
∴ 𝐶𝐶 ≈ 𝐶𝐶𝐸𝐸
V
Ad 𝐶𝐶 =
𝜖𝜖0𝐴𝐴𝑑𝑑
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Adhesion of SMA and hydrogel
Yuk, H., et al. (2016). "Tough bonding of hydrogels to diverse non-porous surfaces." Nat Mater 15(2): 190-196.
Tough bonding between shape memory alloy and hydrogel was achieved by silane coupling reaction
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Demonstration of Capacitive ionic sensor operation
(Normal) (Pressed)
20222426283032343638
0 10 20 30 40 50
Capa
cita
nce(
pF)
Time(s)
Capacitive ionic sensor with SMA successfully operated by finger pressure
V
Ad 𝐶𝐶 =
𝜖𝜖0𝐴𝐴𝑑𝑑
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Demonstration of Capacitive ionic sensor operation
1.6
1.65
1.7
1.75
1.8
1.85
0 10 20 30 40 50
Capa
cita
nce(
nF)
Time(s)
Heating
1.95
2
2.05
2.1
2.15
2.2
2.25
2.3
0 20 40 60 80 100 120 140
Capa
citn
ace(
nF)
Time(s)
Cooling
Confirm capacitance change, however very small signal-to-noise ratio, and capacitance changes by contact surface
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Summary
Scheme of proposed self-regulating shape memory alloy robots with ionic skin
Joule heating
Two-way SME (High T
shape)
Strain sensing
Voltage control
Two-way SME (Low T shape)
Strain sensing
Voltage control
Significance of this study
Sensitive sensing system
Skin-like soft compliance
Simple layer structure
Temperature sensitive shape change
Rapid response to the situation (Temp.)
Structural materials
Two-way SMA Capacitive ionic sensor
Fast and strong reversible actuation controlled by joule heating with simple system
Thank you for your kind attention
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Supplementary
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Supplementary
Beams: Pure Bending (4.1-4.5) MAE 314 – Solid Mechanics Yun Jing Beams: Pure Bending.
Thickness : 0.8mm 기준으로,
Diameter = 2cm → 4% Compressive / tensile strain
Diameter = 2.5cm → 3.2% Compressive / tensile strain
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Supplementary
A1, B1, B2 → High permanent strain
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Yuk, H., et al. (2017). "Hydraulic hydrogelactuators and robots optically and sonicallycamouflaged in water." Nat Commun 8: 14230.stresses. We further demonstrate that the
agile and transparent hydrogel actuators and robots perform extraordinary functionsincluding swimming, kicking rubber-balls and