Easy tuning of fractional-order holds to reduce transient energy consumption of lightly damped resonant systems

In this study, the authors show that it is particularly advantageous to use the fractional-order hold (FROH) instead of the zero-order hold (ZOH) in the digital control of lightly damped resonant systems, as far as transient energy consumption is concerned. First, they show that for a typical digital controller choice FROH reconstruction may well produce a continuous-time signal with less associated energy than ZOH reconstruction. Second, they focus on lightly damped resonant systems, where high energy savings are likely to occur because of the initially swinging nature of the discrete-time control signals driving these systems. Then, they propose an easy procedure to tune the FROH, which is not bound to z-domain controller design, and is therefore radically different from most, if not all, procedures published so far. Finally, they provide some simulation-based application examples confirming the significant control energy reduction attained, in excess of 50%, while not hindering the output performance.