[Doug Leppard]

We use PD of PID for the turn. We might add I later but it turns well now.

We use wheel encoders.

P = (left wheel count)*turnratio - right wheel encoder count

Turnratio = the ratio of the radius of the inside and outside turns. Smaller the ratio the larger the turns.

Then practice doing that with just P before you do move onto ID.

BTW to know when a turn is done, if you subtract one wheel count from the other it will give you the difference and that will give you the number of degrees no matter how large or small the turn is. For instance an 180 turn on our bot is about 600 encoder clicks diference between wheels or about 3.3 clicks per degree difference.