Lecture 1: Overview on Animal Locomotion

Control systems are closely coupled

=

(controller)

(plant)

Feedforward Control

Control systems are closely coupled

=

Control systems are closely coupled

Control systems are closely coupled

Feedback Control

Forcing the issue

groundreactionforce

forceexerted byleg

groundreactionforce

shor

teni

ng

body

Force sensor

Forcing the issue

Ground reaction forces vary with time.

Forcing the issue

Forcing the issue

=

=

Forcing the issue

Forcing the issue

Leaving the straight and narrow

Leaving the straight and narrow

Leaving the straight and narrow

Muscles are more than motors

sarcomere

Muscles are more than motors

strain

stre

ss

strain(length/length)

stress(force/area)

stim

extensor

flexor

3) measureforce

2) stimulateIn phase

1) oscillatemuscle

Muscles are more than motors

activatehere

strain

stre

ssslope = stiffness

changingactivation

phase

Muscle do not have to work as motors to function.

Muscles are more than motors

Muscles are more than motors

Physeter macrocephalus (Sperm Whale)largest toothed whale

20 meters long50,000 Kilograms70 year lifespan

pan-global distribution200,000 population

Central Nervous System

Central Nervous System

Central Pattern Generator

motornerve

sensorynervedorsal

ventral

Musculoskeletal System

sarcomere

Musculoskeletal System

myosin power stroke = 10 x 10-9 Mwhale length = 60 M

~1010 ratio

Musculoskeletal System

Musculoskeletal System

Musculoskeletal System

Musculoskeletal System

myoglobin

Musculoskeletal System

Indohyus, 48 mya

Musculoskeletal System

Musculoskeletal System

Musculoskeletal System

HydrodynamicForce

Velocity, U

Force = ½ C S U2 C = force coefficient of flukeS = Surface area of flukeU = velocity = density of sea water

Hydrodynamics

path of fluke

thrust

+lift

thrust

-lift

Hydrodynamics

thrust

+lift

Emits sound at 230 decibels!

Sensory Systems

Can dive to 3 Kilometers

Higher Order Locomotion

Lecture 1: Overview on Animal Locomotion