OPTIMAL DIGITAL REDESIGN OF CONTINUOUS-TIME SYSTEMS USING FRACTIONAL-ORDER HOLD

This paper proposes a novel optimal digital redesign technique using f ractional-order hold (f.o.h,) for finding a dynamic digital control la w from the available analog counterpart and for simultaneously minimiz ing a quadratic performance index, A method for converting the dynamic digital control law into a static one, through a tuning parameter, is also presented. The proposed technique can be applied to a system cas caded with a more general class of reference inputs than simple step i nputs, and the developed digital controller can be implemented via low cost microcomputers. The superiority of using the fractional-order ho ld over the zero-order hold and the first-order hold is exploited. (C) 1997 John Wiley & Sons, Ltd.