No speed don't matter. Speed around 50 RPM is OK.
I'm sorry if I'm asking the same thing over and over. I'm still doing my design. So the power of the motor could change. The load that needed to be carried is 150Kg. that wont change.
For that I need large motors with high torque and motor controllers that can be controlled through Arduino.
Is it possible, Or am I asking too much from the Arduino................