We want to make a 3kg sumo robot with Arduino UNO. We have been doing our first programing experiments with temporal full-rotation servos, and now we wan't to choose some good ones and buy them.
We know most sumo bots use gear motors, but we would have to learn how to program them, and we have seen some sumos with servos, the problem is the torque ( we don't know if something like 15kg/cm is too much, too litle or what) and the rpm, since servos usually are slow.
We would appreciate any hint you could give us about the magnitudes of torque and rpm usually used
First off, past the issue of speed, I don’t think putting 7lbs on top of servos is going to fly…
In terms of drill motors --I have used them and I have 2 DeWalt drill motors on my robot Walter. I would not recomend them. They are pretty amazing in terms of power and handy in that you have a motor, gearbox and a threaded output shaft all in one case --they are also amazing in terms of how much power they can actually draw. If they are fully stalled, 50, 60 or even 70 amps can be drawn. When running normally, they still draw around 10 amps each. One more issue is the fact that they are designed to run much better forward than reverse and because one motor will be on the “other” side of the robot, one motor will always be running “backward”. This can be a royal pain in the butt to get and keep your motors balanced (going the same speed). Bottom line: if you go with drill motors, be prepared for A) a huge controller and B) constant tweaking to keep them happy.
You may want to look at the motors used for electric windows in cars. They are worm-drive, pull around 3amps a peice, and come in right and left models.
