Digital redesign of uncertain interval systems based on time-response resemblance via particle swarm optimization

In this paper, a novel design approach based on time-response resemblance of the closed-loop system via particle swarm optimization is proposed to improve performance of the redesigned digital system for continuous-time uncertain interval systems. The design rationale of the proposed approach is to derive a digital controller for the redesigned digital system so that step response sequences corresponding to the extremal sequence energy closely match those of their continuous counterpart under the perturbation of the plant parameters. By suitably formulating the design problem as an optimization problem, an evolution framework incorporating three PSOs (particle swarm optimizations) is presented to derive a set of optimal parameters for the digital controller. Computer simulations have shown that time responses of the redesigned digital system having an interval plant have a better resemblance to their continuous-time counter part in comparison those obtained using existing open-loop discretization methods.