Decelerating a line following robot without affecting PID Control

When I reduce the speed I tuned my PID values for, the robot wobbles and has difficulty following the line. Is there a way to decelerate and stop the robot without affecting it’s position on the line? I’m using the Pololu QTRC sensor array.

Has anyone used a PID control loop on encoder values to keep the speed of two motors synchronized while taking a sharp turn?


Your questions seem related, so I merged the two topics. Generally, it is possible to have a PID loop use feedback from a sensor like an encoder instead of the QTRC sensors. Creating a loop that runs off of both sensors is more complicated and it might require considerable experimentation to get working well. Have you tried retuning your PID parameters since you slowed the robot down? That might be the most straightforward way to get smooth motion.