An Optimal Sample-Data holds by using a Bi-Objective criterion: Trade off between the Phase Delay and the Stability Robustness

Abstract

In this paper an optimal data-holding scheme is introduced which compensates the undesirable effects of ZOH. This effect will be improved by using a simple optimal filter, therefore the optimal data-holding scheme is consist of a standard ZOH and a filter. For designing this optimal filter two type cost functions or performance measures are defined in which phase delay or robust stability are considered. In this paper, firstly an optimal filter for minimizing these two cost function will be introduced which its coefficients is optimized by using the Imperialist Competitive Algorithm (ICA) method. Secondly a bi-objective cost function is presented in which both the phase delay and robust stability are considered and then the optimal filter will be designed for minimizing this new cost function. The Simulation and Exprimental results show that efficiency of the proposed optimal filter or proposed data-holding scheme is more than that of the previous optimal filters in each cost function.