“…[12,34] consider to optimum performance by using genetic algorithm in the stabilizing region. Some other researchers try to guarantee a performance specification for the closed-loop system by robust H ∞ design approach combining with the stabilizing domain [35]. It has to be noted that by extending the work [13,16,22], the problems of PI/PID stabilization of second-order delay processes has been discussed in [12,20,21], where, however, the result is limited to some special second-order delay processes (see Remark 3).…”