Let's Make Robots!

tank treads and wheels

hay guys i was just wondering about the advantages of using tank treads and /or wheels....or any other types. efficiency? stability? does it have a large affect ?

thanx for your help

Jordan

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fluroblue's picture
Your a huge help thanx so much
fluroblue's picture
Thanx so much! One last thing is there a formula to work out which servo or motor you would need?
ignoblegnome's picture

Look at the torque of your motors compared to the weight of your robot.

Torque is measured in lbs-ft (or N-m). You have to factor in the radius of your wheels/treads. Divide the torque by the radius. If you have four motors, your total torque is 4x the torque of an individual motor. You want your motors to be able to move MORE than the weight of your robot, or it will just sit there straining.

fluroblue's picture
Im guessing its so its easier to turn?? More control?
fluroblue's picture
Ive seen 1 or 2 projects that use servos on the treads...is this better than the regular motor?
ignoblegnome's picture

A servo modified for continuous rotation gives you a gear motor with its own control electronics (including internal h-bridge), so it can be controlled by a single pin from your microcontroller.

Depending on your project, a continuous rotation servo may be a great choice. Most servos are pretty small, so large robot platforms will probably need motors rather than servos.

ignoblegnome's picture

Advantage: Treads give you a lot of traction, because there is so much surface area.

Disadvantage: Treads can be hard to turn on, because there is so much surface area.

lumi's picture

With treads you just need 2 driven wheels but a 4x4 chassis need 4 driven wheels to be steered like treads or 2 driven wheels and 1 or 2 steering wheels.

The terrain where your bot is moving is also to be considered, treads are better in mud like Geir mentioned.

Geir Andersen's picture

I don’t think that there is much advantage of using treads if you’re not running your robot in mud or on a slippery surface.
But it looks cool :-)