Turn 90 Degrees

[Alan Anderson]

Originally Posted by MikeWasHere05

Whats the formula to figure out how many times the wheel needs to turn to go 90 degrees?

You'll have to start by figuring out how far the wheel has to travel. Then you can divide by the circumference of the wheel to turn that into the number of revolutions.

To compute the required travel, you'll need to know the position of the stationary center of rotation and the distance from that point to the wheel. If you're trying to turn by applying power to one of the rear wheels, the other wheel is the stationary point and the turning radius is the distance between the wheels. If you're going to apply forward power to one wheel and reverse power to the other, the stationary point is directly between them and the turning radius is 1/2 the distance.

Then just use the simple formula for the circumference of a circle (C = 2*pi*r) and divide by four to find out how far the wheel has to go for a quarter turn. Now divide by the circumference of the wheel itself et voila! you now know how many revolutions the wheel must make to perform the 90 degree turn.

Making the wheel turn that many times is left to you as an exercise.

[Salik Syed]

i think it is only simple to do it mathematically w/ a 2 wheel drive robots... .use the distance between two wheels as your turning diameter multiply that times pi for circumferance... now to turn 90 deg it is the (circumferance / 4 )/(wheel circumfrence) to get revoutions of wheel needed....
now if you have four wheels i think it gets trickier because the radius along which each wheel / side turns seems to be uncalculable ...easily ... at least i can't think of a way... also the other side kinda affects it...