I. Introduction
There are many studies on using genetic algorithms (GAs) or simulated annealing algorithms (SAAs) or both to optimize the parameters of proportional-integral-derivative (PID) controllers. Immune genetic algorithm [1], which was proposed in 2007 by Li, is used to optimize the parameters of a PID controller, and the controller is used in a water level control system. An improved genetic algorithm [2], proposed by Wang, is used to optimize the parameters of a PID Decouping Controller, and this conrtoller is used in a variable flow heating system. Three different PID controllers based on a type of SAAs [3], proposed by Zhang, are used to deal with the constant disturbance of a SMT axial motion control system. Genetic algorithms [4] and simulated annealing algorithms [4] were respectively used to optimize the parameters of robot arm PID controllers by Kwok. An effective and hybrid optimization strategy [5], which integrates the parallel structure of GAs with the controllable jumping property of SAAs, was proposed by Wang, is used to estimate the parameters of models and set parameters for controllers.