Comparison between first-order hold with zero-order hold in discretization of input-delay nonlinear systems

In large sampling period nonlinear systems, the Taylor series method was used to improve the performance of the controller. First-order hold (FOH) and zero-order hold (ZOH) are used respectively in the discretization of input time-delay systems. The sampled-data representation of FOH and ZOH are both described. The mathematical structure of new discretization schemes are proposed and characterized as useful methods of establishing concrete connections between numerical and system theoretic properties. The performances of the proposed discretization procedure are compared between FOH with ZOH. Various sampling rates and time-delay values are adopted to inspect the proposed method. The results demonstrate that the proposed discretization scheme can assure the system precision requirements even under the situation of a large sampling period. FOH and ZOH have their own advantages respectively for different input signals.