huy pham ngoc wrote:
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i want to control 2 motors at the same time
because of a robot project.It sounds simple
I want my robot remember every speed on his
way (actualy these are total counts of each encoder.

Why not store position rather than speed ? Ramp the robot speed up to some speed after no collision events perhaps, but why worry about SPEED if POSITION is what you want. Integrating a speed/time graph to get position is fine, (dead reckoning) clever and all that, but tends to be unreliable and inaccurate. If you can measure trajectoru directly, then do so !

Steve