Advanced Variable Structure PI controllers

With the advance of digital control hardware the simple but effective proportional-integral-derivative (PID) control technology is moving towards a higher level of performance and robustness. A more general class of variable structure (VS) PID has derived from original PIDs to improve their performances and capabilities. This paper revises the main properties of VS regulators and proposes a novel VS PI controller that combines the advantages of popular PIs with the more flexibility of VS controllers. The proposed regulator is compared with the classic PI over several examples taken from the literature, including first, second and fourth order dynamical systems. An experimental set-up is implemented on purpose using AVR^®32 Microcontrollers in a hardware in the loop approach to validate the simulation results in a more realistic environment.