Wednesday 25 May 2011 Task Assignment

Subject: Viscosity control in polymer extrusion
Date and Location: 25 May 2011 14:00 - 15:00, 7th floor Conference Room, Ashby
Attendees: Kang Li, Minrui Fei, Xueqin Liu (Amy), Jing Deng, Dajun Du, Weihua Deng, Wanqing Zhao (Horace), Long Zhang (Will).
Message: None

Task assignment

Dajun & Weihua

  • Compare state-of-the-art control strategies, especially the wiener control method. (MPC, LQR, Optimal control, Robust Control, $H_{\infty}$, …)
  • Give us a presentation on your findings.

Will & Horace

  • Literature survey on wiener model identification
  • Have a look at Prof Bai, E. W.'s recent papers on modelling with less data
  • Look for both time and frequency based modelling methods
  • Fuzzy control - Horace

Jing & Amy

  • Controller-based fault detection and diagnosis, this stage is used to direct the control scheme - Amy
  • Give a presentation to describe the extrusion process, what are the important factors? first principal equations? Laws? …
  • Look at different model approaches, input-output? or others.


  • Melt quality includes viscosity and thermal homogeneity.
  • It may be not suitable to control the screw speed.
  • Two main aspects: control (distributed control) and optimization.
  • fist stage - Model free control, second stage - incremental learning (online learning)
  • Multi-scale system, control and modelling


  • Investigate energy transfer of the whole process, which is useful to design control system.
  • Advise to find the key physical factors at first.
  • Multi-scale control conbimed with wavelet networks.


  • Prof S. L Shah paper shows some work on modelling of viscosity through screw speed and melt temperature