Multi-leggedrobots

28.01.09 Presentation on multi-legged robots by Sewan Aleanakian, 2008 2

Table of contents ● Introduction● Different types of multi-legged robots● Different gaits● Special examples

– BigDog– StriDER

28.01.09 Presentation on multi-legged robots by Sewan Aleanakian, 2008 3

Multi-legged robots● Walking robots● Very flexible● Can travel where wheels or tracks would fail● Climbing is possible

28.01.09 Presentation on multi-legged robots by Sewan Aleanakian, 2008 4

Different types ofmulti-legged robots

● Hexapods (six legs)– Most common type of legged robot– Simple in design and control

● Tetrapods (four legs)– Dynamic motion should be used because of fewer

legs● Bipeds (two legs)

– Mostly humanoid robots

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Different gaits● Hexapods

– Wave gait (one leg at a time)– Ripple gait– Tetrapod gait

● Tetrapods– One leg at a time– Dynamic walking (BigDog)

● Tripods– Actuated passive dynamic locomotion (STriDER)

28.01.09 Presentation on multi-legged robots by Sewan Aleanakian, 2008 6

Wave gait● Only one leg moved at once● Robot always stands stable on five legs● Slowest but most stable gait

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Wave gait

28.01.09 Presentation on multi-legged robots by Sewan Aleanakian, 2008 8

Ripple Gait● Two legs are moved at once (or shortly after

each other)● Four standing legs● Faster than wave gait but still very stable

28.01.09 Presentation on multi-legged robots by Sewan Aleanakian, 2008 9

Ripple Gait

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Tripod gait● Two groups of legs, each with three legs,

alternately● Three legs moving, three legs standing● Fastest stable hexapod gait

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Tripod gait

28.01.09 Presentation on multi-legged robots by Sewan Aleanakian, 2008 12

One leg at a time● One leg moving, three standing● Only stable gait for tetrapods● Slow but simple and stable

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One leg at a time

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BigDog

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BigDog● Most advanced tetrapod robot● Height: 0,7 m● Can carry up to 150 kg● Hydraulics powered by gasoline engine● Very fast through dynamic motion● Can recover from stumbling

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BigDog

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STriDER

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STriDER● Self-excited Tripedal Dynamic Experimental

Robot● Height: 0,9 m (Version 2) / 1,8 m (Version 1)● Very energy efficient through actuated passive

dynamic motion● Tall (good for sensors)● Simple concept

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STriDER

28.01.09 Presentation on multi-legged robots by Sewan Aleanakian, 2008 20

Thanks for your attention

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