[oddjob]

PID's are a great way to exert control over motors. The drive wheels are driven by motors. Put the two together.....

Specifically, with friction losses and gearbox/pwm/motor variability, low speed robot movement could be enhanced if the drive wheel motors have software PID control. We usually do that by writing our own drive software, but if it can be done with existing libraries, why reinvent the wheel (ha ha).