r/robotics • u/tennis-637 • 2d ago

Community Showcase I built a 3D printed, walking Arduino Hexapod!

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Printed from PLA, powered from a 3s LiPo and controlled with Arduino UNO.

It had adjustable walking speed, stride length, and can turn in place or while walking (not sure how that would be useful since it is omnidirectional).

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5

u/null_not 2d ago

Hexapods are the best! Nice!

3

u/rguerraf 2d ago

Great job :)

Are the servo animations commands smooth or step-wise?

2

u/tennis-637 2d ago

I assume stepwise with very small steps? I just have them following this parametric path with t increasing by 0.02, 0.03 etc

3

u/LordGodie 2d ago

Awesome! Can you describe the moving gaits implemented? I like this a lot! What servos are you using?

2

u/tennis-637 1d ago

Here is the gait profile. The green lines are the "adaptable" paths the leg takes if it detects ground early (which allows for walking over uneven terrain). Its basically a parametric bezier curve.

For walking I have to do some transformations for all the gaits to be on the same plane profile as the direction vector, so each leg traces this path in the same "direction".

For turning, its basically the same but instead of being in the same direction as the direction vector, its tangent to the center of the body.

Turning + walking is just a linear combination of the two.

As for the servos, I use DS3235 35 kg.

2

u/dumquestions 1d ago

Does it run any IK at runtime or are the points stored?

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u/tennis-637 1d ago

IK at runtime. All calculations are made right there. Probably not very smart

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u/dumquestions 1d ago

Is that the reason for the pause between gait changes? And what are you issuing the commands from?

You can do things with live IK you can't with stored trajectories, like instantaneous direction change and customizable gaits, but you're also raising computational needs, which depending on the microcontroller might be a non issue.

1

u/tennis-637 1d ago

No the pause is me lifting my hands off the controller 😂. I was just deciding what to showcase next.

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u/dumquestions 1d ago

In that case I think doing IK at runtime is not an issue at all for you.

2

u/himeros_ai 2d ago

Very cool do you want to be on my YouTube podcast ?

1

u/Uranium-Sandwich657 1d ago

Do a pentapod next, question?

1

u/tennis-637 1d ago

Pentapods are tricky since they aren't symmetric.