Dynamical modelling and control of plastics extrusion processes

Kochhar, A. K.; Parnaby, J.

doi:10.1016/0005-1098(77)90042-5

Cited by 71 publications

(25 citation statements)

References 7 publications

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“…Costin, Taylor, & Wright, 1982a for an overview). In (Kochhar & Parnaby, 1977) system identification methods are applied to the problem of modeling a single screw extruder; specifically, discrete time dynamic models of the dependence of the output temperature and pressure on the screw revolution speed are estimated from I/O data. Moreover, linearity of the extrusion process has been verified on a wide range of operating conditions.…”

Section: Introductionmentioning

confidence: 99%

Design of a feedback control system for real-time control of flow in a single-screw extruder

Previdi

Savaresi

Panarotto

2006

Control Engineering Practice

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The topic of this paper is the design and experimental testing of a prototype feedback control system for the regulation of the volumetric flow in a polymer single-screw extruder. Flow regulation is achieved by means of joint regulation of the temperature and the pressure at the die. The overall controller architecture is constituted by three control sub-tasks: the inner-loop control of the local temperatures along the barrel; the outer-loop control of the temperature at the extruder output; the control of the pressure at the extruder output. In this work, the whole design procedure (modeling, controller design, and testing) is presented. Extensive tests have shown that the system reacts rapidly to changes in the operating conditions and effectively rejects disturbances due to unexpected changes in the quality of the material. The achieved regulation provides very small steady state errors both for pressure and temperature. Moreover, it is shown that this control system is a cost-effective alternative to mechanical volumetric pumps. r

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Section: Introductionmentioning

confidence: 99%

Design of a feedback control system for real-time control of flow in a single-screw extruder

Previdi

Savaresi

Panarotto

2006

Control Engineering Practice

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“…Kochher and Parnaby used stochastic techniques to obtain the dynamic model of the extrusion process. 6 Hassan and Parnaby used model-referenceoptimal steady-state adaptive computer control 7 to achieve mass flow rate and product quality control. The mass flow rate was inferred from the die-inlet melt conditions of temperature and pressure.…”

Section: Introductionmentioning

confidence: 99%

In-line viscosity fuzzy control

Chiu

Pong

2000

J. Appl. Polym. Sci.

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“…Parnaby et al [26] and Kochhar and Parnaby [27] modelled the extrusion process parameters by using a time series technique. Linearised models relating to small perturbations of the screw speed were identified by observing corresponding changes of the melt pressure and temperature at the die.…”

Section: A Control Schemes Based On Laplace Transform or Time Seriesmentioning

confidence: 99%

Single screw extrusion control: A comprehensive review and directions for improvements

Abeykoon

2016

Control Engineering Practice

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Polymer extrusion is usually a complex process, particularly due to the coupled nature of process parameters, and hence highly prone to fluctuations. Although a number of different approaches have been attempted in research/industry over the last few decades for extrusion control, it is still experiencing some problems in achieving consistent product quality. Presently, most of the polymer processing extruders are equipped with PID controllers mainly for the control of the screw speed and barrel temperatures in their set limits. It seems that only both of these controllers are commonly used as the major aids of process control to achieve the required melt quality. Although, the quality of the melt output (i.e., a thermally homogeneous melt output which is constant in quantity and quality over the time) is the key variable in polymer extrusion, only a few control techniques are available which make control decisions by observing the actual melt flow quality. Therefore, the development of new control strategies which consider the actual melt quality, perhaps incorporating industrially popular nonlinear techniques such as artificial intelligence, should be highly valuable. In this work, a critical evaluation is made on the state-of-the-art of the previous control approaches in polymer extrusion in industry and research while identifying their limitations. Then, some of the possible directions for future research and also to develop an advanced process control strategy are presented by eliminating a few of the existing limitations.

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Dynamical modelling and control of plastics extrusion processes

Cited by 71 publications

References 7 publications

Design of a feedback control system for real-time control of flow in a single-screw extruder

Design of a feedback control system for real-time control of flow in a single-screw extruder

In-line viscosity fuzzy control

Single screw extrusion control: A comprehensive review and directions for improvements

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