Comparison between integer order and fractional order controllers

This paper presents a comparison between fractional order controllers and integer order controllers. The well-known PID is the integer order controller chosen whereas the generalized PID and the CRONE (“Commande Robuste d'Ordre Non Entier” which stands for fractional order robust controller) are the fractional order controllers studied. Another big difference between these controllers is that the structure of the PID and the generalized PIλDμ is a priori fixed whereas the structure of the CRONE is a posteriori deduced from the loop shaping. Results show that the fractional order controllers are more robust when small variations appear in the plant and their behavior is more suitable regarding the user specifications requirements.