中文摘要：

过程系统的控制、仿真与优化往往都是依赖于高性能的模型。特别是对于基于模型的控制方案中，模型不仅要高精度地拟合过程的稳态特性，还必须具有大范围描述过程动态行为的能力。对于化工非线性对象pH中和过程，由于pH中和滴定曲线的严重非线性、pH反应的滞后性以及外部干扰的复杂性，使得其成为过程控制中典型的控制难题。

英文摘要：

The modeling and control of pH neutralization processes is a difficult problem in the field of process control. A multi-modeling method using an improved k-means clustering based on a new validity function is proposed in this paper. There are some common problems, including the number of clusters assumed as a priori knowledge and initial cluster centers selected randomly for classical k-means clustering. The proposed algorithm is used to compute initial cluster centers and a new validity function is added to determine the appropriate number of clusters, then partial least squares （PLS） is used to construct the regression equation for each local cluster. Simulation results showed that multiple models using the proposed algorithm gave good performance, and the feasibility and validity of the proposed algorithm was verified.