关键词: 非线性动态系统, 建模, Hammerstein模型, 粒子群优化（PSO）算法

Abstract: A novel modeling method for a type of nonlinear dynamic system is discussed in this paper.First of all，it is supposed that the original nonlinear dynamic system can be expressed by Hammerstein model. And then，the nonlinear transfer function of Hammerstein model is converted to the same form as linear one，thus generating the intermediate model.After that，the parameters of the intermediate model are obtained using Particle Swarm Optimization（PSO） algorithm.Finally，through the relations of the parameters of intermediate model and that of Hammerstein model，the parameters of the nonlinear static subunit and linear dynamic subunit are derived.Thus the original nonlinear dynamic system is modeled.In order to further enhance the performance of modeling，an Improved Particle Swarm Optimization（IPSO） algorithm is also proposed.The rationality and efficiency of the presented algorithm are demonstrated by simulation examples.

Key words: nonlinear dynamic system, modeling, Hammerstein model, Particle Swarm Optimization（PSO） algorithm