CIESC Journal ›› 2020, Vol. 71 ›› Issue (3): 1103-1110.DOI: 10.11949/0438-1157.20191539

• Process system engineering • Previous Articles     Next Articles

Modeling and control strategy for packing-stage of injection molding process based on PWA fusion model

Yaobo HUANG(),Jiaxin LIU,Zuhua XU(),Jun ZHAO,Zhijiang SHAO   

  1. National Laboratory of Industrial Control Technology, College of Control Science and Engineering, Zhejiang University, Hangzhou 310027, Zhejiang, China
  • Received:2019-12-18 Revised:2019-12-26 Online:2020-03-05 Published:2020-03-05
  • Contact: Zuhua XU

基于PWA融合模型的注塑过程保压段建模及控制策略

黄耀波(),刘佳新,徐祖华(),赵均,邵之江   

  1. 浙江大学控制科学与工程学院,工业控制技术国家重点实验室,浙江 杭州 310027
  • 通讯作者: 徐祖华
  • 作者简介:黄耀波(1994—),男,硕士研究生, 21432009@zju.edu.cn
  • 基金资助:
    国家重点研发计划项目(2017YFB0603703);NSFC-浙江两化融合联合基金项目(U1509209)

Abstract:

The injection molding is a typical batch process and consists of three stages: filling, packing-holding and cooling. Packing-holding is an important stage to determine product quality and has obvious nonlinear and time-varying characteristics. Piece-wise affine (PWA) model can effectively describe the dynamics of packing-holding stage, but the hard switching of PWA model will lead to the output jump problem. Therefore, we propose a novel time-partitioned PWA fusion model, in which the switching regionis introduced between adjacent sub-models and model fusion is realized by linear weighting method. Then, an identification algorithm based on separable nonlinear least-squares is developed to estimate model parameters. Based on this, a multi-model PID control method based on internal model tuning is designed.Experimental results of injection molding machine show the effectiveness of the algorithm.

Key words: injection molding process, PWA fusion model, separable least-squares, multi-model PID control

摘要:

注塑过程是典型的批次过程,由注射、保压、冷却等阶段构成。保压段是决定制品质量的一个重要阶段,且具有较大的非线性和时变性。分段仿射(piece-wise affine, PWA)模型能够有效描述保压段的特性,但是PWA模型硬切换方式会导致输出跳变问题,因此提出一种基于时间划分的PWA融合模型,在子模型切换过程中引入切换区间,通过线性加权方法进行模型融合,并采用基于分离最小二乘的辨识方法进行参数估计。在此基础上,设计了基于内模整定的多模型PID控制方法。注塑机实验结果表明了算法的有效性。

关键词: 注塑过程, PWA融合模型, 分离最小二乘, 多模型PID控制

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