Ok I see there has already been a bit of discussion on motor speeds but I am still a little lost on a good solution.
The bot will have lots of general use purposes but atm I want to use it for my openCV line follower see https://www.youtube.com/watch?v=Konj7L9EGPE
I did notice another thread of line follower using openCV somewhere but can't find it now, if any others are working on this let me know as I have the computer vision working very well.
I want to be able to control and steer accurately a bot with 2 drive wheels at front and a caster following wheel at the back. The bot needs to be able to drive at constant speed even as battery charge changes and also it would be much better if I could sink both motors for accurate steering.
Atm I just use BrickPi.MotorSpeed[port2] = speed to set motor speed but the actual speed that the motor turns will depend upon the battery level. It seems it more like sets the power level rather than the rotation degrees per time.
Also for steering I just set "BrickPi.MotorSpeed[port2] = speed" on one motor and "BrickPi.MotorSpeed[port2] = speed*percentsteer" on the other motor