running on the moon

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Running on the Moon Francois Decuir

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Page 1: Running on the moon

Running on the MoonFrancois Decuir

Page 2: Running on the moon

IntroductionIn reduced gravity <0.5g, running requires

less energy than walking

• In space, the pressure inside space suits is high enough that it helps support the total weight

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0006614#pone.0006614.s003

Page 3: Running on the moon

IntroductionSpace suits affect the walk-run transition by

mobility restriction, changes in stability, and increased joint mechanical work

Page 4: Running on the moon

VideoThe pressure in the space suit keeps the knee from buckling. This makes walking expend more energy.

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0006614#pone.0006614.s003

Page 5: Running on the moon

IntroductionFroude Number

By modeling walking as an inverted pendulum, we find that walking occurs only when Fr≤1.

Page 6: Running on the moon

IntroductionApollo Number

The Apollo number is defined as the Froude number multiplied by the inverse of the mass ratio M.

When no space suit is present, M=1 and Ap=Fr

Page 7: Running on the moon

Variablesv=velocityL=hip height or center of mass heightM=ratio of human carried mass to total

transported massg=gravitational accelerationα&β=shape and location of the state transition

Page 8: Running on the moon

PhysiologicalThe physiological variables include the length

of the leg, L, and the mass ratio, M.When attempting to manipulate the Apollo

number, the variable M can be changed. This can give either a higher or lower chance to be in a “run” state.

Page 9: Running on the moon

Important models

Change in M to keep the Apollo number constant.

Probability that gait=1

Page 10: Running on the moon

RecreationMATLAB was used to recreate

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0006614#pone.0006614.s003

Apollo Number

Walk

or R

un

sta

te

Page 11: Running on the moon

Alteration

To allow a shorter astronaut to run at the same speed as a taller astronaut, the weight of the space suit must be altered.

Lower space suit weight/Shorter hip height

Higher space suit weight/ Longer hip height

Ap

ollo

Nu

mb

er

Mass Ratio

Page 12: Running on the moon

PossibilitiesEmergency situation occurs

Page 13: Running on the moon

BenefitsOptimizing space suits for travel to the Moon

and Mars

Page 14: Running on the moon

ConclusionIn a suit with a higher mass, M, the walk-run

transition will occur at lower speedsAs loads reduce the self-support, M, walking

becomes possible at higher velocities

Page 15: Running on the moon

Questions