A methodology for the practical implementation of fractional-order event-based PID controllers

Achieving high control performance while minimizing resource usage is a key challenge in industrial systems. Fractional-order PID (FOPID) controllers offer enhanced performance over integer-order PID. Meanwhile, event-based control architectures reduce resource use and costs. However, integrating FOPID control with event-based architectures is challenging, as standard discrete-time approximations’ accuracy of fractional dynamics degrades under non-uniform sampling. This paper presents a practical method to implement FOPI and FOPID controllers in an event-based framework. Building on industrial PIPlus and PIDPlus architectures, the approach uses state-space realizations of fractional operators, enabling the controller’s internal states and output to be updated in closed form only at event times. A simulation study compares the proposed method against an existing direct-discretization approach, which represents the only alternative available in the literature to implement event-based fractional-order controllers, by considering different controller configurations. The results show that the proposed method reproduces the response of the reference time-based controller more accurately. In particular, it achieves substantial reductions in the integrated absolute error between the event-based response and the reference response obtained with standard periodic sampling ( I A E P index), with average improvements ranging from 38% to 68% across the different controller configurations considered. These findings suggest that the proposed state-space approach is a reliable solution for deploying existing fractional-order controllers in event-based architectures while preserving their intended closed-loop dynamic behavior.