Intro Design process iSprawl Stickybot Conclusion Spinybot 1

Bio-inspired robot design

Sangbae Kim

Biomimetic robotics Lab MIT

Intro Design process iSprawl Stickybot Conclusion Spinybot 2

Outline •  Vision •  Design approach

–  Bio-inspired design •  iSprawl

–  Hexapedal running robot

•  Spinybot –  Climbing robot using micro spines

•  Stickybot –  Gecko-inspired climbing robot with

Directional adhesives

•  Conclusion & future work –  Organic robotics

iSprawl

Spinybot

Stickybot

Intro Design process iSprawl Stickybot Conclusion Spinybot 3

Vision

•  Mobile application •  Unstructured/unexpected

environment •  Compliant interaction

Biological inspiration

Bio-inspired robot design

Conventional robot design

•  Grounded application •  Structured/expected

environment •  High-precision/speed position

control w/ stiff interaction

Intro Design process iSprawl Stickybot Conclusion Spinybot

Biological inspiration for locomotion?

4

Mechanical requirement

Biological requirement

Manufacturing

Energy source

Actuation

Control system

...

Grow

Eat

Evolve

Survive

Reproduce ...

Morphology

Energy exchange

Balance ...

Locomotion

Intro Design process iSprawl Stickybot Conclusion Spinybot 5

Passive compliance can replace the leg?

Oscar Pistorius

“Mechanical advantage”

1.  25% less energy expenditure

2.  Nearly three times higher elastic energy recovery than human ankle

Photo: from dailymail.co.uk For limited tasks, passive mechanism may replace function of complicated system

Intro Design process iSprawl Stickybot Conclusion Spinybot 6

iSprawl - Power transmission system for Independent hexa pedal robot

Intro Design process iSprawl Stickybot Conclusion Spinybot 7

Biological Example for the Sprawl Robots

•  Death-head cockroach Blaberus discoidalis –  Fast (up to 10 body/s)

–  Traverse rough terrain (up to obstacles 3X of hip height)

Blaberus discoidalis running over fractal terrain

(Full, et al., 1998)

Intro Design process iSprawl Stickybot Conclusion Spinybot 8

Functional Principles Learned from Biology

•  Open loop control •  Passive self-stabilization

–  Compliant hips

•  Thrusting legs •  Differential leg function

(Sprawled Posture)

Active Thrusting

Force

Sprawled Posture

Primarily passive

trochanter- femur joint

(Full, et al., 1998)

(Full, et al., 1991)

(Garcia, et al., 2000, Meijer and Full 1999)

SLIP model

Intro Design process iSprawl Stickybot Conclusion Spinybot 9

Sprawlita

•  Mass - .27 kg •  Dimensions - 16x10x9

Leg length - 4.5 cm •  Max. Speed 70+ cm/s

4+ body/sec •  Hip height obstacle

traversal

Intro Design process iSprawl Stickybot Conclusion Spinybot 10

Flexible Power Transmission

Gear Motor

Slider

Flexible region (Arbitrary path)

Rigid region (Force output)

Rigid region (Force input)

Flexible cable

Flexible tube

Rigid Shaft Flexible Cable

Rigid Shell Flexible tube

Stroke length

Intro Design process iSprawl Stickybot Conclusion Spinybot 11

Rubber tube

spring

Rotational flexure with friction damper

Axial Leg Spring

Intro Design process iSprawl Stickybot Conclusion Spinybot 12

High speed camera

500 frames/sec Treadmill

Reflective Marker

Intro Design process iSprawl Stickybot Conclusion Spinybot 13

iSprawl Running

Intro Design process iSprawl Stickybot Conclusion Spinybot 14

Spinybot

• Length: 58cm

• Weight: 0.4 kg

• Motor pattern : fixed servo motor

• Battery: Lithume –polymer

• Gait: alternating tripod

• Developed with Alan Asbeck

Intro Design process iSprawl Stickybot Conclusion Spinybot 15

Climbing Experts Source of inspiration: geckos and insects

Photos: Mark Moffett

Intro Design process iSprawl Stickybot Conclusion Spinybot 16

Intro Design process iSprawl Stickybot Conclusion Spinybot 17

Stickybot

•  Smooth wall climbing robot •  Weight : 400g •  Length : 38cm w/o tail •  Actuation: 12 Servo motor •  Highly underactuated leg and foot

design •  Utilize Directional adhesive