In this paper, a real-coded genetic algorithm is proposed for identification of time
delay systems from step responses. FOPDT (First-Order Plus Dead-Time) and SOPDT (Second-
Order Plus Dead-Time) systems, which are the most useful processes in this field, but
are difficult for system identification because of a long dead-time problem and a model
mismatch problem. Genetic algorithms have been successfully applied to a variety of
complex optimization problems where other techniques have often failed. Thus, the
modified crossover operator of a real-code genetic algorithm is proposed to effectively
search the system parameters. The proposed method, using a real-coding genetic
algorithm, shows better performance characteristics when compared to the usual area-
based identification method and the directed identification method that uses step
responses.
