bio inspired design - lecture5. bio energy_springs

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Bio-Inspired DesignBioEnergy: Biological Springs

Faculty of Mechanical, Maritime, and Materials EngineeringDepartment of BioMechanical Engineering

Just Herder

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© 2008 Just L. Herder

• Feb 17, 8:45-10:30, room F, Just• Contents: bioenergy: storing energy in springs (neck

of giraffe, chameleon, grasshopper, tendons in human ankles), vibration (birds, flying insects), etc.

Lecture 3: BioconstructionBioenergy (biological springs)

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• Springs: muscles and tendons• Vibration examples: insect wings, legged locomotion• Storage examples: chameleon tongue, neck ligaments• Engineering example: human-friendly robotic arm

Lecture 3: BioconstructionBioenergy (biological springs)

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© 2008 Just L. Herder

Vertebrates: joints

• Synarthroses: hardly movable (sutures in human skull)• Amphiarthroses: slightly movable (cartilage attachments in

ribs and vertebrae disks)• Larger range of motion:

• Ball-and socket (e.g. hip, GH-joint)• Ellipsoidal (e.g. fingers)• Condyloid (e.g. knee joint)• Saddle (e.g. part of the wrist joint)• Pivot (e.g. radius/ulna joint)• Hinge (e.g. elbow joint)• Plane/gliding (e.g. scapula joint)

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© 2008 Just L. Herder

Muscles: Arthropods (e.g. spiders)

• External cuticular skeleton• Harder and softer sections• Motion by regulating blood pressure through

contraction of thoracic muscles• Per leg 7 segments and 30 muscles for extension,

none for flexion (dead spiders curl up)• Regular molting required (growth)• Also during ‘soft period’ motion possible

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© 2008 Just L. Herder

Muscles: Crabs

• Also hard enclosure• Danger of tendon passing though joint axis• Limited range of motion

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Muscles: return spring

E.g.: Scallops (Pecten, Cyprina, Mytilus)• Compliant joint tends to open• Open scallop from the inside!• Eliminates need for agonist-antagonist pair• Without muscle force open

Trueman (1953) in Alexander (1988)

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© 2008 Just L. Herder

Muscles: Energy Storage

Energy Storage• Tendon material (e.g. Achilles tendon, foot arch)• Muscle fibres (for small length changes).• Ligamentum nuchae (spinal ligaments of hoofed

animals)• Mesogloea (collagen fibres in anemones and jellyfish)• …

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© 2008 Just L. Herder

Ligaments: Energy Storage

Hoofed animals• Cow, giraffe, deer, camel, sheep• Head statically balanced by ligament• Potential energy exchange• Easy conversion from feeding to alert• Sleep with neck in vertical plane

Figure from Dimery, Alexander and Deyst (1985)

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Ligaments: Energy Storage

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© 2008 Just L. Herder

Ligaments: Energy Storage

Dimery, Alexander and Deyst (1985)

Sheep:• Force in ligament in alert position

around 10 N• Force in ligament in feeding position

around 80 N• Sufficient for equilibrating head• Strain up to 0.8 (close to breaking)• Experiments with deer and camel

yield similar results

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© 2008 Just L. Herder

Ligaments: Energy Storage

Ligamentum Nuchae

With1) σ≈6E5 N/m2, V≈5E-4 m3 (500cc), E≈8E5 N/m2:

W≈100 J

(equiv. 5 kg over 2 m)

FW Fdx dFk

= = =∫ ∫2 2 2

2 2 2F F L Vk EA E

σ= =

1) Data and figure from K.S. Gellman et al. (2001)

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© 2008 Just L. Herder

Elbow Orthosis

J.C. Cool et al. (1976)

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Elbow Orthosis

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Safe Robotic Arm

• Harmless, small actuatorsElimination of gravity forcesAdjustable springs: artificial muscles

• Harmless, soft controlNo trajectory controlEquilibrium point hypothesis control

• Construction

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Current robots are unsafe

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…which can be undesirable

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© 2008 Just L. Herder

Static BalancingAny conservative force can be canceled out!

AnglepoiseTMMeager Bridge (Amsterdam)

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© 2008 Just L. Herder Herder and Tuijthof (1998)

Anthropomobile balanced arm

Four degrees of freedom

Two zero-free-length springsfor perfect static balance

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© 2008 Just L. Herder

Anthropomobile balanced arm

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© 2008 Just L. Herder

Artifical MusclesMcKibben actuator

tubing

braiding

JE Surentu (1999)

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© 2008 Just L. Herder

B. Hannaford, J.M. Winters, C.P. Chou (1994)

Artifical MusclesMcKibben actuator

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© 2008 Just L. Herder

Artificial MusclesForce-length characterisitic of a silicon McKibben muscle

140 150 160 170 180 190 200-10

0

10

20

30

40

50Force[N]

Length [mm]

0

P1

P2

P3

P4

P5

P0

JE Surentu (1999)

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© 2008 Just L. Herder

Extension of the model

).(.. 20

22

0

20

1 83 LL

LDPF −=

π

⎟⎟⎠

⎞⎜⎜⎝

⎛+==

dLd

dLdV

dLdUF y

yx

xrtub ε

σεσ2

F dL P dV dUtub. .= − +

F F F= +1 2

JE Surentu (1999)

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© 2008 Just L. Herder

Artifical MusclesMeasured characteristics of corrected McKibben muscle

100 120 140 160 180 200 220-10

0

10

20

30

40

50Force[N]

Length [mm]

0

P0

P1

P2

P3P4P5

JE Surentu (1999)

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Compliant control

• Safe• Natural

• Biomechanics• equilibrium point hypothesis (Feldman, Bizzi et al.)

• Robotics• impedance control (Hogan)

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© 2008 Just L. Herder

Equilibrium point hypothesisFeldman, Bizzi et al.

equilibrium point hypothesis 2D illustration

K1 K2

ϕ

JE Surentu (1999)

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© 2008 Just L. Herder

Equilibrium point hypothesisFeldman, Bizzi et al.

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© 2008 Just L. Herder

Range of motion

a

r

(B)

a

r

(C)

a

r

(A)

Muscle attachment points

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Muscle-lever System

x

z

yθ

3

2

1ϕ

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Actuator locations

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© 2008 Just L. Herder

45 67.5 90 112.5 135

0

22.5

45

67.5

90

P1 = 5 [bar], P2 = 5 [bar], P3 = 5 [bar]

phi, ( -Mphi )

thet

a, (

-Mth

eta

)

Natural behavior Muscle moments elbow

Elbow angle

Endorotationangle

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45 67.5 90 112.5 135

45

67.5

90

112.5

135

P4 = 0 [bar], P5 = 0 [bar], P6 = 0 [bar]

psi, ( -Mpsi )

eta,

( -M

eta

)

Natural behavior Muscle moments shoulder

Shoulder angle up-down

Shoulder angle left-right

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Anthropomobile balanced arm

Variable stiffness control

McKibben actuators

Statically balanced

Inherently safe

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© 2008 Just L. Herder

ARMON (Mark I)

Herder, Tomazio, Cardoso, Gil and Koopman, 2002

SergioTomazio and Luis Cardosorecieving the PremioEngenheiroJaime Philipeaward

JorineKoopman

Ms B.

Sergio Luis

Patient performingimportant ADL with

device

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ARMON (Mark II)Team: 2 ME and 2 IDE students

( ) 0det ==

JJqx &&

Sabine Gal (IDE)

Wendy van Stralen (ME)

Tonko Antonides (IDE)

Pieter Lucieer (ME)

Herder, Stralen, Lucieer, Gal and Antonides, 2004

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© 2008 Just L. Herder

ARMON (Mark II) Patients with the device

Herder, Stralen, Lucieer, Gal and Antonides, 2004

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© 2008 Just L. Herder

ARMON (Mark III)Patients with the product

www.microgravityproducts.com

Herder, Vrijlandt, Antonides, Cloosterman, Mastenbroek, 2006

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© 2008 Just L. Herder

ResearchBalancing of balancers

It moves ‘energy-free’…

…but adjusting to another payload is not energy-free!

R Barents, WD van Dorsser, BM Wisse, JL Herder (2006)

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ResearchBalancing of balancers

…but adjusting to another payload is not energy-free…?

…unless the energy comes from anotherspring!

R Barents, WD van Dorsser, BM Wisse, JL Herder (2006)

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ResearchBalancing of balancers

R Barents, WD van Dorsser, BM Wisse, JL Herder (2006)World Patent: WO2007/035096 (2007-03-29)

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© 2008 Just L. Herder

Energy-free adjustmentBalancing of balancers

R Barents, WD van Dorsser, BM Wisse, JL Herder (2006)

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© 2008 Just L. Herder

Energy-free adjustmentBalancing of balancers

R Barents, WD van Dorsser, BM Wisse, JL Herder (2006)

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© 2008 Just L. Herder

Energy-free adjustmentBalancing of balancers

R Barents, WD van Dorsser, BM Wisse, JL Herder (2006)

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© 2008 Just L. Herder

Energy-free adjustmentBalancing of balancers

R Barents, WD van Dorsser, BM Wisse, JL Herder (2006)

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© 2008 Just L. Herder

Energy-free adjustmentBalancing of balancers

R Barents, WD van Dorsser, BM Wisse, JL Herder (2006)

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© 2008 Just L. Herder

Energy-free adjustmentBalancing of balancers

R Barents, WD van Dorsser, BM Wisse, JL Herder (2006)

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© 2008 Just L. Herder

Energy-free adjustmentBalancing of balancers

R Barents, WD van Dorsser, BM Wisse, JL Herder (2006)

ASME IDETC Best Paper Award

2008

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© 2008 Just L. Herder

Muscles: Energy Storage

• Oscillations: human legs, Walibi (kangaroos), and hoofed animals

• Proof by measuring metabolic energy uptake during walking, and by stretch measurements of tendons

• Main advantage: reduces the amount of work that needs to be done by the muscles (or actuators)

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© 2008 Just L. Herder

Tendons: Energy Storage

• Human foot: main storage in Achilles tendon and foot arch

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© 2008 Just L. Herder

Tendons: Energy Storage

High efficiency: • Energy dissipation collagen around 7% (Ker et al.,

1986)• Energy dissipation resilin around 3% (Weis-Fogh,

1960, in Vogel, 1998)• Not a big difference in efficiency (93% vs 97%) but

heat generation about a factor of 2 (!)

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© 2008 Just L. Herder

Muscles: Energy Storage

• Oscillations: human legs, Walibi (kangaroos), and hoofed animals

• Proof by measuring metabolic energy uptake during walking, and by stretch measurements of tendons

• Main advantage: reduces the amount of work that needs to be done by the muscles (or actuators)

• This principle has been applied in running robots (perhaps less complicated than walking robots!)

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Muscles: Energy Storage

Marc Raibert

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© 2008 Just L. Herder

Muscles: Energy Storage

• Sarcophaga (flesh flies)

• Bistable spring mechanism

Alexander (1988)

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© 2008 Just L. Herder

Muscles: Energy Storage

• Longitudinal muscles: tend to shorten the thorax and make Scutum buckle upward, so drive wings down

• Dorso-ventral muscles: restore shape Scutum, raisewings.

• Note that also Scutum stores energy (buckling)• Wings run faster than fly’s brain (1 action potential for

40 wing cycles!)Ennos (1987) in Alexander (1988)

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Storing gradually, releasing instantly

Grasshopper leg: • Overall length 40 mm• Extensor lever ratio on tibia around 1:35, so for 15 grams of

thrust, 500 grams muscle force• This is average, peak up to 1500 grams• Big force through ‘herring’ arrangment of muscle

WJ Heitler, http://www.st-andrews.ac.uk/~wjh/jumping/

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© 2008 Just L. Herder

Storing gradually, releasing instantly

WJ Heitler, http://www.st-andrews.ac.uk/~wjh/jumping/

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© 2008 Just L. Herder

Storing gradually, releasing instantlyTongue of chameleon• < 0.1 sec to prey, 500 m/s2, 6 m/s• More powerful (3kW) than any known muscle…

JH de Groot, JL van Leeuwen, 2004Video available at http://noorderlicht.vpro.nl/artikelen/17184463/

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Storing gradually, releasing instantly

A Tongue at restB Force builds up, axial

elongationC Tip slides of skeleton,

acts as inversion of soap sliding out of hands

Extraordinary degree of function integration

JH de Groot, JL van Leeuwen, 2004