  In this paper, modification of the classical PID controller and development
of open-loop control mechanisms to improve stability and robustness of a
differential wheeled robot are discussed. To deploy the algorithm, a test
platform has been constructed using low-cost and off-the-shelf components
including a microcontroller, reflectance sensor, and motor driver. This paper
describes the heuristic approach used in the identification of the system
specifications as well as the optimization of the controller. The PID
controller is analyzed in detail and the effect of each term is explained in
the context of stability. Lastly, the challenges encountered during the
development of controller and robot are discussed. Code is available at:
https://github.com/sametoguten/STM32-Line-Follower-with-PID.
