In the [wiki:ControlSystems/SoftwareTeam/Training/GettingStarted/ClosedLoopControl last example] we learned about proportional closed loop control where we helped the robot drive straight by increasing/decreasing power to the left/right motors in proportion to the error between the distance traveled by the left/right wheels.

While proportional control works in many cases, it can take time to achieve the proper power balances, can be slow to react to changes, and in some cases can even oscillate or never reach the proper power levels.  PID control is a more sophisticated solution that takes more factors into consideration:
* P = Proportion - current error
* I = Integral   - accumulated error over time
* D = Derivative - rate error is increasing/decreasing

Code examples are coming soon