11 Control and modelling

11.1 Active sludge plant supervision and quality control

Goals

Metsä-Serla Oy, Kyro Board Mill and Neles Automation (formerly Valmet Automation Inc.) carried out an R&D project at Kyro Board Mill, the target of this project was to utilize the possibilities of the modern automation system in total control of an effluent water treatment plant.

The first experiences of applying fuzzy logic to an effluent water treatment process were gained in 1996 at Metsä-Serla Oy, Kyro Board Mill, in Finland. The results from Kyro indicate a clear increase in the overall controllability of the process. The XDi control solution based on fuzzy logic (nutrient dosage control and the return and excess sludge removal controls) provides over 98 % availability.

Diminishing environmental load

The excess sludge control has optimized the sludge age from 12 to 7 days increasing the amount of excess sludge removal from biosludge cycle. At the same time, there has been an increase in buffer capacity in the biosludge thickening pool due to more efficient sludge drying. The plant also showed a clear improvement in the suspended solids and phosphorus reduction, as well as a remarkable 35 % decrease in the phosphorus acid consumption.

Since fuzzy logic has been in use, the suspended solids load has decreased from about 4.5 kg/t to below 2.0 kg/t, and the phosphorus load from over 4 kg/d to below 2 kg/d. At the same time, the total sludge handling capacity has increased from 36 m3/h to over 52 m3/h. The new control solution has also helped to decrease the usage of polymer from 3.3 kg/t to 1.8 kg/t.

Methods

Efficient management of effluents requires versatile information facilities and intelligent controls. Damatic XDi is a unique platform for integrating information management and controls into one system. Advanced control algorithms, such as fuzzy logic, are applied to embed knowledge and human experience in intelligent control algorithms. Decision making is supported by a dynamic online help facility that can be easily maintained. The comprehensive history database archives laboratory and process measurement data which is transformed into a usable and easily understandable form with user tools.

Project information

Participants

  • Valmet Automation Inc.
  • Metsä-Serla Oy, Kyro Board Mill
  • Tekes

Project dates

Starting 1.11.1995 and ending 31.12.1996

Project volume

Total budget FIM 933.827

Project manager

Jukka Puhakka
Valmet Automation Inc., Neles Automation Group, Control Systems
Lentokentänkatu 11
P.O. Box 237
FIN-33101 Tampere, Finland
Tel: +358 20 483 8035
E-mail: jukka.puhakka@nelesautomation.com

More information

Jukka Puhakka or
Timo Merikoski
Tel: +358 20 483 170
Fax: +358 20 483 84058405
E-mail: timo.merikoski@nelesautomation.com


11.2 Adaptive and intelligent systems in paper machine grade change

Abstract and goals

Grade change on a paper machine or board machine means changing the current paper grade to a new one. Grade change is made by changing machine variables such as speed, stock flow and steam pressures at the same time to provide a fast transition in quality variables such as basis weight and moisture. Because of the complexity of the process the grade change is very demanding operation.

The goal in project was to investigate whether intelligent control and calculation methods can be used to improve the control in the grade changes.

Methods and results

The fuzzy control method was mainly studied in the project. Pilot research was carried out on two Finnish production paper machines and results of the research have been put into use.

Project information

Participants

  • Prosessitutkimus H. Peltonen Oy

Project dates

1.4.1997 - 31.10.1998

Project volume

FIM 355.000

Project manager

Heikki Peltonen, DI
Prosessitutkimus Oy
Laserkatu 6
FIN-53850 LAPPEENRANTA
Tel. +358 5 6243 250
Fax +358 5 4120 949


11.3 Aggregate quality characteristics and control of their effects with a neural network

Goals

  • To recognize the most important concrete aggregate quality characteristics and determine their impact on concrete in its fresh and hardened state
  • To be able to improve control the quality of concrete aggregate already during its production and thus reduce the variation on concrete as the end product
  • To enable more efficient and economical use of the aggregate pits/quarries in the company’s business area and in its strategic expanding areas (Nordic countries and the Baltic Sea area)
  • To test and learn the possibilities for using a neural network to control the concrete raw materials and further extend its use in the steering system for concrete production

Results and impact

  • A Excel–based computer programme has been developed. By entering values of the aggregate quality characteristics, it evaluates the aggregate’s performance in the concrete. When also comparing the available aggregates to the transportation distances one can choose the most economical aggregate combination for concrete production.
  • New, easy to perform and yet reliable testing methods have been developed for aggregate production to gain information on the aggregate quality characteristics.
  • The neural network has been found to be a flexible and useful tool to handle aggregate and concrete technology questions and problems.
  • The aggregate and concrete producers feel more confident when making decisions about aggregate selection. The use of nontraditional aggregates, e.g. crushed and filler aggregates, have increased. This extends the life span and economy of the aggregate pits/quarries, when more of the raw material is used in the processed end use instead of as unprocessed filling.
  • The information gained in this project also helps to direct aggregate production so that one can choose the best production technique, e.g. normal production, washing, impact crusher etc. The best economy is achieved when both the aggregate and concrete production costs are optimized.

Project information

Participants

  • Lohja Rudus Oy, aggregate and concrete producer, project leader
  • Partek Betonila Oy, precast element producer
  • Lappeenranta University of Technology, neural network programmer

Project dates

Starting date 01.01.1995, ending date 31.12.1997

Project volume

Total budget FIM 1.100.000

Project manager

Development manager Hanna Järvenpää
Lohja Rudus Oy
P.O. Box 49
FIN-00441 HELSINKI
Tel: +358-9-503 73 67
Fax: +358-9-503 73 96
E-mail:  hanna.jarvenpaa@lohjarudus.fi

More information

Lohja Rudus Oy homepages: www.lohjarudus.fi


11.4 Analyzer-based process control utilising neural networks and fuzzy logic methods

Goals

The aim of the project was to develop a quality prediction model for the cooking process in a pulp mill. The predictor was to be based on the information received from a developed CLA2000 Cooking Liquor Analyser measuring the alkali content, total dissolved solids and dissolved lignin during the cooking process. Neural networks and fuzzy logic methods were to be the main methods used in the development.

Results and impacts

Kappa number models (Kappa number = the main pulp quality variable in cooking) for different types of digesters were developed. The models gave good results when the feedback data from the final Kappa number was easily available. In cases when the Kappa number samples had to be collected manually, the labour required became too big, and other methods such as reference curves were found to be more reasonable.

Other quality variables such as yield and pulp strength were also studied, and similarly when the feedback data was available the results were promising. However, the data needed to train the networks is not normally collected in the mills, and generalisation of the achieved results remained as question marks in this project.

The achieved results offer a better way to manage the cooking process control. The developed quality predictor is a new product as such, and it also expands the products range of cooking optimising software packages. In addition, it improves the applicability of the CLA2000 Cooking Liquor Analyser.

The project also increased significantly the understanding of the methods used, and at least some level of technology transfer from the university was recognised.

Methods

Principal methods used were backpropagation and Levenberg-Marquardt neural network algorithms and commercial fuzzy logic tools (Matlab). A short study was carried out with linguistic equations. Conventional regression models and reference curve methods were also used.

Project information

Participants

  • ABB Industry Oy, Pulp & Paper
  • University of Oulu, Control Engineering Laboratory
  • Exens Development Oy

Project dates

Started: 1.1.1997, finished: 31.12.1998

Project volume

FIM 2.068.000

4Project manager Raimo Sutinen
ABB Industry Oy
Systems Group
Tyrnäväntie 14, 90400 Oulu, Finland
Tel: + 358 10 22 52144
Fax: + 358 10 22 52140
E-mail: raimo.sutinen@fidri.mail.abb.com

Publications

Sutinen R., Prediction of cooking results using neural networks. Automaatioväylä 5, 1996, (in Finnish).

Lemmetti A., Leiviskä K., Sutinen R., Kappa number prediction based on cooking liquor measurements. Report A No 5, May 1998, Control Engineering Laboratory, University of Oulu.

Murtovaara S., Lemmetti A., Sutinen R., Leiviskä K., Kappa number prediction based on cooking liquor measurements. SPCI proceedings, Stockholm. June 1999.

Lemmetti A., Murtovaara S., Leiviskä K., Sutinen R., Cooking variables affecting the kraft pulp properties. Control Engineering Laboratory, University of Oulu, 1999 (to be published).


11.5 Application of artificial neural networks in the modelling of cold rolling and heat treatment processes

Goals

This project aimed to develop neural network models by using measured process data from Rautaruukki's steel strip production. The main goal was to combine all manufacturing processes into one optimimizing model, using physical and neural models. The desired properties, such as strength, formability and flatness, could be predicted and controlled after each process stage.

Results

In the first stage, neural networks were used to predict the properties of steel strip and to optimise the process parameters in cold rolling. The second stage aimed to predict the mechanical properties of the cold rolled products. Both of these stages have been completed successfully.

Project information

Participants

The project was carried out in cooperation between Rautaruukki Strip Products and the Laboratory of Materials Processing and Heat Treatment at the Helsinki University of Technology.

Project dates and volume

his three year project was completed on 30.6.1997 and the total budget was about FIM 2 million.

Project manager

Dr. Arto Ranta-Eskola
Rautaruukki Steel, Strip Products
FIN-13300 Hämeenlinna, Finland
Tel: +358 3 528 5467
Fax: +358 3 528 5620


11.6 Automatic tuning of intelligent controllers (ATIC)

Goals and results

The ATIC-project comprised of partner companies' confidential R&D projects in which automatic tuning of intelligent controllers was applied in different installations. Under the umbrella of these separate projects all the partners benefited from the experience gained in the different applications.

The versatility and increase in automation of machines and processes have induced a strong growth in the number of the tuning parameters of controllers. This type of development places increasing demands on the knowledge and time of the user.

In order to reduce the period of starting up it is essential to automate the tuning of controllers.  With automatic tuning the impact of users’ different views and interdependencies on tuning parameters can be taken into consideration.

Usually the know-how about installations is very unexact and empirical. This kind of know-how can be put to use with the help of fuzzy logic while designing the controllers.

The aim in the R&D projects was not the generation of new products but the improvement of the subsystems in large-scale entities.  The results have been installed in commercial products such as drilling machines, harvesters, paper machines, different kinds of service and diagnostic systems, to mention some areas of concrete applications.  It can be said that ATIC projects have contributed to the competitiveness of partner companies and led to several commercial applications.

Partners

  • Neles Jamesbury Oy
  • ABB Industry Oy
  • Plustech Oy
  • Tamrock Oy Technology Center
  • Tamlink Ltd
  • Valmet Automation Inc.
  • Tampere University of Technology
  • Helsinki University of Technology

Project dates

ATIC product development project was in progress for 3 years, from 01.03.1995 to 28.02.1998. 

Project volume

The volume of the project was up to FIM 6 million.

Contact person / Project manager

Juha Leppänen
Tamlink Ltd
Hermiankatu 6
P.O. Box 140, FIN-33721  Tampere
Tel: +358-(0)3-3165 100
Fax: +358-(0)3-3165 123
E-mail: Juha.Leppanen@tamlink.fi


11.7 Comprehensive control of product and process information in electronics production

Goals

The real-time information received from the devices on a production line and the products being produced makes the observation and control of the production line more comprehensive than at present. To arrive at comprehensive observation and control, better management of the information flood is needed. The information and knowledge, which are essential from the point of view of the observation and control of electronics production, was gained by combining product and process information. An evaluation prototype of an online production monitoring system was tested in the project. The aim of the evaluation prototype was to estimate the suitability of different methods within the separate subsystems and identify a viable system architecture.

Results and impacts

In the project an evaluation prototype was developed. The system applies fuzzy logic to processing data. The prototype produces a trend of product quality indicators describing the situation of a product and line by extracting and interpreting the data coming from single devices. At a glance the trend gives operators an overall picture of the product and process quality standard achieved on the monitored production line. The hierarchical visualisation method, which has been developed for the system, makes it possible to locate and predict the faults of the production devices and products. The system remains open and easily modifiable. This is important, because several products are often assembled on one production line, and the measurements required by the control system may change not only between products but also between different versions of a single product.

Methods

  • Fuzzy logic
  • Traditional statistical process control methods

Project information

Participants

  • Nokia Mobile Phones
  • VTT Electronics

Project dates

Starting January 1, 1999, ending November 31, 1999

Project volume

FIM 1.250.000

Project manager

Olli Nieminen
Salo, Finland


11.8 Development of a calibration method and new applications [IMA QuarCon Analyser (XRF– bulk material analyser)]

Goals and results

IMA Engineering Ltd Oy  is a global supplier of advanced online xrf -analysers for different types of industrial minerals processing plants.

IMA’s main customer group is cement plants and limestone quarries. Typically, a cement plant can be considered as a vertically-integrated industrial process from mine to ready cement, packed and delivered to final customers. IMA products help cement customers to improve their operations; to make savings in their raw materials handling, and to develop the process.

IMA has developed a distributed online bulk material xrf -analyser system (called QuarCon) for analysis of limestone materials from the conveyor belt for this specific customer group. In the first installations, QuarCon analyser calibration proved to be complicated, and selected models were unstable or had to be modified quite often. In addition, it became apparent that at many quarries “the need to know” chemical composition as early as possible is vital to improve the efficiency of the operation. In such cases, QuarCon should be installed right after the first crushing stage, where lump size is bigger, material bed fluctuations are higher, and generally the environment is more harsh.  It is believed that such a situation is also typical in many base metal mines, so a possible solution to this problem would mean new potential applications.

Parallel developments to improve the performance of QuarCon were started in 1996:

  • An automatic step-forward regression software prototype was tested, and a study to find best commercial regression package was started.
  • Empirical static and dynamic calibration methods were studied in customer deliveries.
  • Methods to measure and to compensate for material bed fluctuations on the conveyor belt were studied.
  • A new calculation method to eliminate or reduce the error due to material fluctuations etc. was developed (today known as smart IQCalc calculation software).
Step-by-step, new ideas and methods were tested in old and new applications, and finally in late 1997, new methods, procedures and new software proved out to give the desired result. The adopted method and procedures include: special arrangement of irradiation and detection with scattering channels to get more rugged and stable models, model selection using a commercial regression tool (product name Statgraphics), procedures to perform static calibration with model selection and testing, and procedure to perform dynamic calibration and testing. Around the same time a new version of IQCalc was developed, and this new smart calculation eliminates e.g. too low or high tons or empty belt situation. Also, it is possible to use automatic model selection, not to forget the possibility of combining and managing situations with analysis results from several analysers and piles at the same time.

A new real-time platform (FIX from Intellution) with Windows NT operating system with smart IQCalc, IQReporter for easy reporting, and some tailored calculation and control software also helped to reach the desired target with ease and speed of calibration in new installations throughout 1998 and after.

After tests and head-to-head comparison with PGNAA method, QuarCon was selected at the RTZ, QIT Fer et Titane project in Canada to analyse titanium ore at their mine in Quebec. This new application and installation has just been completed, and shall be reported in the international press soon. This new application is expected to serve as a reference for base metal applications.

Project information

Participants

The described development was possible only with close cooperation with customers, who were interested in obtaining good performance at new and older installations. 

Project dates

The development project was officially started in early 1997 and ended in December 1997.

Project volume

The total cost was about FIM 1.5 million including estimated work at customers plants.

Project manager

Mr Juha Kaikkonen, technical director
Tel. +358-9-8678 100
Fax: +358-9-86781020).

More information

IMA company and product information is available at the Internet home page: www.ima.fi and in the following publications: Halla Success with IMA, International Cement Review 12/98, Calibration of on-line analysers, International Cement Review 7/1998.


11.9 Dosing control of water treatment chemicals

Goals

The treatment of industrial wastewater is a complex, non-linear process, which has long time delays. In general, there are only few suitable on-line measurements. So, the continuous dosing control of water treatment chemicals cannot be optimised. The aim of this clinic project was to study the capabilities of intelligent methods to control dosing.

Results

In this case, an industrial wastewater treatment process was studied. The impurities of the water were measured as COD, suspended solids, turbidity etc. The current dosing control of chemicals is simple. The dosage is based on the flow rate of incoming wastewater. If the impurity level of wastewater is constant, this control method guarantees the treatment result but cannot prevent the overdosing at certain times. owever, there are often great variations in the quality of water to be treated. With a flow-related dosage of the chemicals the increase in the impurities in the wastewater flow results in insufficient purification. Another problem is that without any feedback control the amount of chemicals cannot be optimised.

A lot of data was collected from the case process. The neural network models were derived from this information. The target was to teach the model predicting the turbidity of purified water on the basis of the flow rate of wastewater, the amount of chemicals and the suspended solids in the incoming wastewater. The MLP (Multilayer Perceptron) models were developed with G2 NeurOn-Line studio software.

The results from the study are promising. The model learnt the process rather well. However, the model should be improved and tested more before it can be used for control purposes.  With reliable models, the process could be controlled so that the amount of chemicals can be optimised.

There have been preliminary discussions about continuing the work.

Project information

Participants

The work was carried out  in co-operation with Control Software Oy, University of Oulu and Kemira Chemicals Oy. The software development was subcontracted by Control Software Oy.  The expertise of intelligent methods was obtained from the University of Oulu.

Project dates

Project started in September, 1999 and lasted for about three weeks.

Project volume

The costs were FIM 118.000.

Project manager

The project manager was Marjatta Piironen from Kemira Chemicals Oy, Oulu Research Centre (marjatta.piironen@kemira.com).


11.10 Finnotzo – air conditioning system for buses

Goals

The goal of the project was to develop temperature regulation inside buses so that both air quality would be maintained and temperature regulation would work with precision under changing conditions. One of our targets was to remodel the unit in order to finish with the best possible result in air circulation. Another important objective in our project was to obtain the best possible raw materials and to use a production method which enables us to speed up assembly.

The results and impacts

We have succeeded in developing a unit suitable for serial production. We used subcontractors for some of the components, but the rest were manufactured in our workshop, which results in shorter assembly times. All this enabled us to give a positive response to short delivery time requests. We have also been able to keep costs down. The unit has better heating/cooling capacities than those of its predecessor, which has made finnotzo our customers’ choice for air conditioning.

We have found a new method for manufacturing the base for the unit by adapting vacuum forming of the plastic raw material.

We have also been quite successful in the development of heating/cooling automatic controls. With the new automatic controls it is far easier to control the internal temperature of a bus than with the old system. With the help of these new automatic controls we have also been able to improve the old controls.

During the project and thereafter we have acquired a lot of new information in different areas of bus air conditioning. We have increased cooperation with the bus bodybuilders in Finland. The cooperation has led to constant improvments in the unit.

Methods

Modeling

The temperature regulation system in buses has been modelled and the models have been experimented by carrying out test drives in varying climatic conditions. A ”datalogger”-type measuring device has been used. Data has been collected from various measuring points, for example the ambient temperature, the internal temperature, the engine’s water temperature and the opening of the magnetic valves on the heat exhangers. With the measured values all the variables have been indentified and taken to the ASCET system, where it has been possible to undertake simulations. All the information gathered this way has been taken to the next level, where the information has been translated into software.

Identification

We studied the temperature regulation process’s basics and characteristics. We also studied and tested all convetional regulation possibilities. Then we identified all the models and functions for application of the fuzzy logic. The fuzzy logic was used to control heating options and to control for exceptional circumstances.

Project information

Participants

Companies:
  • Autojen Kylmälaite Oy
  • Konsul Oy
  • Xortec Oy
  • Proautomatica Oy
  • Muoviura Oy
Research institutes
  • TTKK
  • EMEC Oy

Project dates

1.11.1996 – 31.12.1997

Project volume

Total budget FIM 900.000

Project manager

Timo Kauppinen
Autojen Kylmälaite Oy

More information

www.dlc.fi/autojen

Figure 1. Finnotzo – air conditioning system for buses.


11.11 Fuzzy logic in Vacon frequency converters

Goals

The objective of the project was to use and develop fuzzy strategies in the frequency converter. AC-drives are widely used in industry, typically for cranes, elevators, paper machines, conveyors, winders, and pumps.

Fuzzy logic controllers were developed to control the DC-link voltage of a voltage source inverter. The controllers are activated when an over or under voltage situation appears. Over voltage in the DC-link will appear when the frequency converter attempts to stop a high inertia load (e.g. a large fan ) in a too short a time. The fuzzy logic controller seeks a new deceleration time for the drive in such way that the DC-link voltage will be kept constant. If the supply voltage is lost, the frequency converter has to decelerate to maintain DC-link voltage high enough to keep the drive 'alive'. In this case the frequency converter draws energy from the load.

Fuzzy logic was also used in the torque controller of the Vacon frequency converter. Using fuzzy logic a more reliable product was achieved which is important for industrial customers. Customer-specific controllers and compensators were designed as well. E.g. the frequency converter was used to give an actual value for an external analogue PID controller inside the customer's hardware. Based on the current process state, the actual value was modified by the fuzzy logic in the frequency converter. The frequency converter was used to make a non-linear signal modification and no PLC was needed. This feature caused the OEM customer to choose Vacon’s frequency converter.

Project information

Participants

  • Vaasa Control Oy
  • Sigmateam Ky

Project dates

Project started on 01.02.1996 and ended on 31.12.1996.

Project volume

Total budget for the project was FIM 1,127 million.

Project manager

Veijo Karppinen
Tel: +358-6-212 1210

More information

Ilkka Laukkanen
Tel: +358-6-212 1296

11.12 Higher-level control system for lime kilns

Goals

The goal for the project was to develop a higher-level control system using modern control methods such as fuzzy control and multivariable control algorithms.

The main emphasis in process control was:

  • to minimise emissions
  • to optimise energy use
  • to maximise the lifetime of refractories
  • easier and more stable operation of the kiln
  • to develop tools for remote operation follow-up.

Results

Fuel consumption of the kiln has been lower on average when the control system has been used compared to earlier statistics.

The reduction in emissions cannot be shown.

The lifetime of refractories is normally several years. Temperature peaks that are harmful for refractories have, however, disappeared.

The quality of the product, i.e. burned lime, is defined by residual carbonate. Average residual carbonate has been higher as targeted and the average deviation from the target has been smaller.

Figure 1. Change in residual carbonate deviation with help of fuzzy control

Methods

The control system program was developed jointly with the manufacturer of the DCS.

After testing it was loaded into the DCS of a Finnish pulp mill. A test period of two months was arranged. The control system was not running for the first 30-day-period. The second period was used to compare the difference.

Figure 2. Lime kiln fuzzy control.

Project information

Participants

  • Ahlstrom Machinery Corporation, Savonlinna, Finland
  • Honeywell Oy, Center of Excellence, Varkaus, Finland
  • Enocell Oy, Uimaharju, Finland

Project dates

Start 1.5.1996, end 31.5.1998

Project volume

Budget for the project was FIM 1.055.000.

Project manager

Keijo Savolainen, Director of Sales
Ahlstrom Machinery Corporation, Savonlinna
Phone: +358 15 5761.


11.13 Integrated neural network and hybrid systems modeller for the hot rolling mill pass schedule calculation system

Introduction

A rolling mill pass schedule calculation system calculates the settings  for the rolling mill. The system consists of process models  and several algorithms. The models are based on physical and experimental modelling methods. Neural networks play a significant role in modelling because the phenomenona in rolling are nonlinear and measured data is stochastic.

In this project the main goal was to develop a modelling application that automates modelling, tests the models and gives statistical information about  the model performance, such as std, rmse and  distribution. The application was implemented by using G2 software with its NeurOn-Line and Diagnostic Assistant software tool kits.

Results

The application achieved by this project searches automatically datasets from the rolling results database, scales and filters data, trains and tests the neural network models and saves results and models for pass schedule calculation system. It is also possible to simulate process behaviour, optimise the structure of the model and generate and test hybrid models (neural network  models + analytical models). A configuration tool (net builder) establishes automatically the structure of the model (the number of nodes in hidden layer). Simulations allow the user to generate some data to input into the model, inspect the output generated from data and then save the results. The user can specify the range (min to max) of values and number of increments for a given input. The application displays the output data graphically.

The rolling force models for several types of steel were implemented. The benefits of modelling with this application were more accurate models and a more efficient modelling process than before. In the future it will be possible to generate more general models by using hybrid models.

Methods

Multi-layer perceptron networks with back propagation training algorithm were used for modelling. The net-builder was based on the OLS-method. The models were tested on independent datasets and testing results were analysed statistically. Hybrid models were also tested during the project.

Project information

Participants

  • Outokumpu Polarit Oy, Tutkimusosasto
  • Control Software Oy

Project dates

Project starting date 1.1.1999, project closing date 15.3.1999

Project volume

FIM 100.000

Project manager

Harri Kiviahde
Outokumpu Polarit Oy
95400 Tornio, Finland
Tel: +358 16 453322
E-mail: harri.kiviahde@outokumpu.com

Pekkä Häyhä
Control Software Oy
Veneentekijäntie 4, 00210 Helsinki, Finland
Tel: +358 9 676744
E-mail: pekka.hayha@csoy.fi


11.14 Intelligent dosing control system

Starting status

PCE Engineering is a Finnish engineering corporation, products of which include concrete technology systems and machines. The production is based on projects and products are customized to meet the needs of the client.

Concrete consists of an aggregate material, water and cement. The key factors in producing high quality concrete are mix design, the finest raw-materials and their accurate dosing and proper temperature and moisture of the concrete batch. This research project concentrated on finding the correlation of these key factors and continued the previous research on temperature and moisture control of concrete.

Goals and objectives

Earlier the accuracy of aggregate dosing has varied a lot depending on the operator’s experience and knowledge of dosing parameters at the batching and mixing plant. The goal of the project was to help the less experienced operator to reach better concrete quality by more accurate dosing of aggregates and better control of concrete temperature and moisture.

The first objective of the project was to develop a control system which optimizes the dosing parameters and properties. The second objective was to test and extend the temperature and moisture fuzzy control systems to operate under more diffucult circumstances, i.e. at ready-mix plants.

Results and impacts

The previous Elematic ProMix for Windows batching and mixing plant control system has now been expanded to include also the new temperature, moisture and dosing control systems. These control systems have been tested in both winter and summer and they have performed successfully. According to test results temperature, moisture and dosing controllability have been improved despite the weather conditions and the operator´s experience.

Methods

The control systems were applied to the control of the moisture, temperature and the accuracy of aggregate dosing. The control systems were developed on the basis of  experimental measuring results and expert knowledge.

Project figures

Partners

  • Tampere University of Technology

Schedule

The schedule was orginally from 1.1.1997 to 31.1.1998, but it was extented to 31.12.1998.

Volume

The budget of the project was FIM 1.25 million.

Contact

Mia Kauhanen
Tel: +358 3 549 511
Fax: +358 3 549 5300
E-mail: mia.kauhanen@elematic.com

During Mia Kauhanen´s maternity leave (8.6.1998 – 2.8.1999)

Teemu Mattila
Tel: +358 3 549 511
Fax: +358 3 549 5300
E-mail: teemu.mattila@elematic.com

11.15 Method for measuring the liquid steel level in a basic oxygen furnace (LD-converter)

Introduction

In a BOF, pig iron containing about 4 % carbon is refined into raw steel by using oxygen lancing. From a control point of view, it is very important to know the actual distance between lance tip and hot metal surface. The traditional method involves dipping a steel rod into the bath between two heats. This requires 5 to 8 minutes, which is a very long time relative to the actual blowing time (less than 20 minutes).

Goals

The main requirements set for the method to be developed were the following:

  • Measurement range up to 15 metres
  • Accuracy + 2 cm
  • Ambient temperature 0 - 70 oC
  • Reflecting metal surface, temperature 1300 to1600 oC
  • If possible, also the slag/metal interface or thickness of slag layer
  • Very dusty and vibrating environment
  • Max. measuring time 2 minutes
  • Connectable to process automation system

Results and Impacts

Tests at Fundia Wire Koverhar plant

A test series was conducted in November-December 1997 at Fundia Wire Oy Koverhar plant. Koverhar operates two 50-tonne BOFs. The radar was encapsulated in an enclosure made of stainless steel.

The opening for the lance and sublance was used to access the hot metal level.

The tests convinced us that the microwave method gives consistently accurate information on the hot metal surface, both before blowing and after blowing, plus the converter bottom.

A permanent installation on both converters at Koverhar was carried out in 1998.

Main impacts

Technically it is now possible to measure the bath level for every heat. Exact bath level information is passed to the process automation system which, among other things, controls the lance and oxygen blow rate. The benefits of the new method are:

  • Savings in converter lining costs
  • Improved steel yield because of decreased iron losses to the slag and because of decreased slopping
  • Improved productivity due to the shorter measurement time
  • Less variation in end-point carbon and temperature
  • Improvement in working conditions

Methods

Microwave radar

It became obvious that the microwave radar, tested already in the 70s, is perhaps the most suitable method [1]. The test radar by Krohne was a continuous wave device working at a 10 GHz frequency band. Setting of parameters and processing of measurement information is carried out by software. The basic software classifies the echoes and selects the strongest signal representing the air/metal interface. The device is equipped with a PC CAT interface for connection to a PC. For connection with the process automation system a standard 4 to 20 mA interface is used.

Figure 1. Microwave radar based measurement system at Fundia Wire Koverhar Plant.

Project information

Participants

  • Finx Oy (coordinator)
  • Fundia Wire Oy Ab (steel manufacturer)
  • Euroquest Oy (algorithms)
  • Imamic Oy (radar technology)

Project dates

Start: August 1, 1997, finish: February 28, 1998

Project volume

Budget: FIM 118.000
Actual: FIM 107.700

Project manager

Erkki Saarelainen
Finx Oy
Revontulentie 6
FIN-02100 ESPOO, FINLAND
Tel: +358-9-4351602
Fax: +358-9-4351603
E-mail: erkki.saarelainen@finx.fi

More information

Please contact project manager or visit our web page http://www.finx.fi .

References

[1] Kari Leppälä: Development of hot metal level measurement for LD converters. Thesis for Engineering Degree, Helsinki University of Technology, 1975 (in Finnish).


11.16 Model-CC: neural network technology for process modeling

Goals

To develop a product which uses neural network technology in process modeling and optimization.

As a result of the project a new process modeling tool, the Model-CC quality control  system, has been developed. This system has been used in pilot tests in several pulp and paper mills.  The Model-CC system has used to predict the quality variables of the end product. In some cases it is also possible to obtain a recommendation for control action. The Model-CC system is not used in a closed control loop. The main goal when implementing the system in the mill was to reduce the amount of broke.

At the moment there are two online projects in the implementation phase. In one project, the Model-CC system is being used to reduce the grade change time in a paper machine. The Model-CC system’s user interface is implemented on the display of the process automation system. Before the grade change the system makes a recommendation for the nip pressure of nip rolls and thus reduces the time delay when paper thickness is in quality tolerance.

In the other project, three quality variables are being predicted. The Model-CC system is used to give a control recommendation if any of them goes out of quality tolerance.

Methods

The Model-CC system is built up from several commercial products, including a database, a neural network program and data acquisition programs. The specifications, data acquisition drivers, tools for maintaining the system and user interfaces are produced by Control Software Ltd. Predictions of quality variables and recommendations for control actions are based on neural networks models. In most implementing projects emphasis is on collecting process data and process knowledge in cooperation with the customer’s personnel.

Project information

Project was started by Corintec Oy. The business was sold to Control Software Oy on 1.11.1998.

Participants

  • Euroquest Oy, Lappeenranta
  • Taipale Engineering, Lappeenranta
  • Enso Publication Papers Oy, Anjalankoski
  • Laminating Papers Oy Ltd, Kotka
  • Metsä-Botnia Oy, Kemi
  • Metsä-Rauma Oy, Rauma
  • Valmet Paperikoneet, Pansio

Project dates

Starting 2.1.1996, ending -

Project volume

FIM 4.184.393

Contact information

Pekka Ruusunen
Control Software Oy
Veneentekijäntie 4
FIN-00210 Helsinki, Finland
Tel: +358 9 676744
Fax: +358 9 670077
E-mail: Pekka.Ruusunen@csoy.fi


11.17 Neural networks for material properties

Goals

Thermodynamic properties of substances are needed in numerical simulation of industrial processes, e.g. in process and control design, safety analysis, and operator training. Properties that are often required include temperature, density, mass fractions, enthalpies, and partial pressures under different process conditions. Rapid calculation of these properties is also necessary in the measurement of several process variables needed for process control in distributed control systems (DCS).

Conventional algorithms for the calculation of thermodynamic properties typically consist of several iterative steps including calls to complex functions and interpolations in tables based on both theory and experimental data. The iterative algorithms are too slow to be used in dynamic process simulators that should run faster than real time. Methods based on tables and linear interpolations are fast, but in practice limited to cases with only two or three inputs.

The goal of this work was to study the feasibility of using neural networks (NN) to calculate the material properties of substances.

Results and impacts

A total of 7 neural network models were identified for different phases of H2O (Fig. 1). The preset accuracy limit of 1% of the output range was achieved in every point of the training and validation sets.

Figure 1. Schematic representation of neural networks for different phases of H2O.

The NN models proved to be considerably faster than the conventional series development approximations that usually are applied to H2O. In typical test cases, the NN models were only 15 times slower than linear interpolation used in the dynamic process simulation program APROS. However, the number parameters of the identified networks were 800 times smaller than the breakpoint values for linear interpolation. Linear interpolation is feasible only when the number of inputs is one or two. The NN models can also be used in higher dimensional cases.

These results showed that NN models are useful for the description of thermodynamic and other material properties of substances when the number of inputs is higher than two. Only few parameters need to be stored and the calculation is rapid enough for dynamic simulation.

Based on this study a new project “Modeling of thermodynamic properties of substances by neural networks” started in March 1998. In that project a general method was developed for the generation of fast neural network models approximating the thermodynamic properties given by existing methods.

Methods

Feedforward networks with one hidden layer of sigmoid neurons were used throughout the work. The chosen multilayer perceptron (MLP) network structure has been theoretically proven to be capable of approximating any function having a finite number of discontinuities with arbitrary accuracy. The generalization feature made it possible to train the network with a representative set of input-output pairs and then also achieve sufficient accuracy with new inputs of the validation set. Use of the same neural network architecture in all cases made it possible to develop a general training procedure. The Lewenberg-Marquardt optimization algorithm was used for the estimation of the weights and cross-validation for choosing the number of hidden neurons.

Project information

Participants

  • Finntech Finnish Technology Ltd
  • VTT Automation

Project dates

1.4.97 – 30.05.97

Project volume

FIM 100.000

Project manager

Osmo Nojonen
Finntech Finnish Technology Ltd
P.O. Box 402, FIN-02150 Espoo, Finland
Tel: +358 9 456 6148
E-mail: osmo.nojonen@finntech.fi

Publications

R. Lilja and J. J. Hämäläinen (1999), Modeling of Thermodynamic Properties of Substances by Neural Networks, Proc. International Joint Conference on neural Networks (IJCNN '99), Washington, DC, July 10-16, 1999.


11.18 Neural networks in the control of blast furnace processes

Goals

The aim of the project was to study the applicability of neural networks for the control of blast furnace processes. The main goal was to develop neural network applications which can be used in controlling the horizontal and vertical temperature profiles as well as the horizontal gas distribution profiles of the blast furnace.

Results

At the beginning of the project the existing neural network applications in iron and steel industry were examined. The current status of knowledge was mapped by these investigations. This knowledge formed a basis for further development in this project.

New neural network based applications were developed for the monitoring and interpretation of blast furnace wall temperature and gas distribution measurements. These applications were implemented in the Rautaruukki Raahe Steel’s blast furnaces. Operating experiences have been positive and applications are utilised daily in the process control. In addition, a system for the monitoring and interpretation of signals from the blast furnace stockrods was developed.

Based on the result of this project, Rautaruukki Engineering has develop a Blast Furnace Neural System, or BFNS for short, which makes it easier to observe and handle profile data on vertical blast furnace lining temperatures and horizontal temperature/gas analysis profiles. The BFNS consists of on line neural network applications, which classifies the measured blast furnace data into one of the predetermined classes. The results are shown online on special displays (Figure 1). From these displays operators can observe the types of profiles and how they have changed during the selected viewing period. The BFNS also contains an environment for training and testing, which can be used to update online applications whenever needed.

The BFNS forms a new desired link between charging and blast furnace performance. The main benefit offered by the BFNS is an improved utilisation of the blast furnace wall temperature and gas distributions, which means more accurate and reliable process control. The BFNS has been taken as a new product for Rautaruukki Engineering, which is a business unit of the Rautaruukki Group. The first implementations of the BFNS outside Rautaruukki Steel were made in 1999.

Figure 1. An Example of a Blast Furnace Neural System display.

New projects relating to neural networks, genetic algorithms and fuzzy logic have been started as a result of this project.

Methods

Both supervised and unsupervised neural network architectures were studied in this project. It was observed that neural network models using supervised learning are effective when features of process data can be easily extracted. Neural networks using supervised learning are useful whenever it is possible to define input/output patterns but when it is not known exactly what is between them. The power of unsupervised learning methods is their ability to extract the basic features of data. Therefore they are especially suited to situations where extraction of typical features from a large and complicated dataset is required.

Performance of the neural network models was evaluated against various statistical models. These evaluations proved that there are many difficult tasks of this type where it is very difficult or even impossible to develop a good model with conventional methods but where neural network models are very powerful.

Project information

Participants

The project was carried out in cooperation between Finnish Universities and Rautaruukki Co.

Project dates

Project started in autumn 1995 and it concluded at the end of 1998.

Project volume

The total budget was about EUR 1.2 million.

Project manager

Martti Miettinen
Rautaruukki Oyj Engineering
www.rautaruukki.fi/Engineering.


11.19 Opportunities offered by mathematical modelling at Rautaruukki Steel Strip Products

Goals

The objective of this project was to evaluate mathematical modelling possibilities in strip production, and identify those that are likely to result in clear benefits with small effort, cost, time and risk. This survey was also to result in a broader picture of mathematical modelling possibilities that could be considered and where the new ideas fit in. Ideas from this project are likely to result in significant benefits.

Mathematical modelling is an important part of the research and development activities at Rautaruukki. Rautaruukki focuses on higher level automation as one of the important activities in corporate research. Mathematics is often at the core of automation systems. Therefore it is important to have a good idea of what can be achieved and what needs to be done. This project was expected to result in a better view of the possibilities of mathematical modelling in strip production. This expectation has been fulfilled.

There is virtually no limit to the possibilities of mathematical modelling in strip production. This work has therefore focused on realistic possibilities, particularly those which are either seen as needs or as good ideas worth considering. The ideas have been gathered during discussions with personnel at Rautaruukki Strip Products division, as well as from literature.

Results

The results of the project are the ideas and an evaluation of their value. Most of the information has been recorded in the form of lists, which are divided into five areas:

  • Short descriptions of the ideas that were mentioned during the project.
  • A list of ideas without descriptions.
  • A list of the participants, and the two evaluation committees which commented on the ideas.
  • The packages of the ideas. Many ideas were related and overlapping, so at a certain stage some ideas were fused together into packages.
  • A list of the better ideas. The list reflects the opinions of the author of the report, and takes into account primarily the comments of the two committees, but also an overview of the ideas in the list, their potential to Rautaruukki, the technical risks, the size of the possible projects and available technical background and/or production data. The list can be expected to have a slight bias in favour of empirical modelling.
  • >

Project information

Participants

  • Rautaruukki Strip Products
  • Abhay Bulsari, AB NONLINEAR SOLUTIONS OY

Project dates

November 1998 - April 1999

Project volume

The total budget was FIM 50.000.

Project manager

Dr. Arto Ranta-Eskola
Rautaruukki Steel, Strip Products
FIN-13300 Hämeenlinna, Finland
Tel: +358 3 528 5467
Fax: +358 3 528 5620


11.20 Paper web break sensitivity indicator (PAJE)

Goals

This project has developed a paper web break sensitivity indicator for a paper machine. This indicator(s) is based on analysis of the process measurements online in order to make current predictions of paper web breakage propability. This information can be used to direct actions of the operators and maintenance personnel to identified problem areas.

Paper web breaks are one of the three factors affecting on the net efficiency of a paper production line. Paper web breaks cause about 3% efficiency decrease in a paper machine production. The other two are shutdowns and produced broke amount corresponding about 4% and 6% of the efficiency decrease, respectively. These figures are highly process and machine dependent.

It has been estimated that 1% increase in net efficiency increases the annual profit of a large paper machine by $ 1.5 million.

Figure 1. The wet end of a paper machine.

The project has produced 2(+1) independent paper web break sensitivity indicator versions.

The development of these indicators has required methods to manage the vast amount of process measurement data covering long time periods. The requirement to be able to combine process measurement data with other information sources and to analyze them together has lead to practical solutions, e.g. a visual reporting tool. A data collection and processing process is also defined and has been in use in the project.

This project has been working in paper making process area that cannot currently be controlled well enough. The project has developed tools to handle process measurement analysis online. Research institutes have learned more about the process and they have developed their tools and knowledge accordingly. The paper manufacturer UPM-Kymmene has been able to utilize the results of this project’s web break analysis and reporting tool. With this tool they can accurately identify where in the machine the breaks are occurring over a long time and are thus able to direct their maintenance activities. Although the problem of web breaks is not completely solved, the need remains for tools which help to run a paper machine more economically.

Methods

The project has developed 2 (+1) independent indicator versions. These different versions operate using different principles: one version operates as a Case Based Reasoning (CBR) system. This indicator version compares the current process measurement state to several state samples representing different amounts of web breaks. The closeness of the current state to samples relates to the web break sensitivity of each sample. This approach is using the linguistic equations method developed by Esko Juuso.

The second approach is based on univariate signal feature extraction and following preprocessing perceptron network. Each process measurement is analyzed to identify features whose existence and magnitude tells how much that signal is behaving in a risk-increasing way. The training phase adapts a sigmoidal function to each process measurement to make a separation between risk-increasing and risk-reducing features. In the analysis phase, separate signal risk factors are summed up to give a single risk figure. The process delays and signal setting times are taken into account yelding a risk figure that is related to time.

Project information

Participants

  • Valmet Corp.
  • UPM Kymmene Corp.
  • Oulu University, Department of Process Engineering
  • Åbo Akademi, Institutionen för Informationsbehandling,
  • Helsinki University of Technology, Control Engineering Laboratory
  • Tampere University of Technology, Automation and Control Institute
  • General Electric, Corporate Research and Development

Project dates

1.9.1995 – 30.12.1999

Project volume

FIM 5 million

Project manager

Kari Oinonen
Valmet
P.O. Box 587
FIN-40101 Jyväskylä, Finland
Phone: +358 20 482 6194
Mobile: +358 40 733 8908
E-mail: Kari.Oinonen@valmet.com

Publications

Timo Ahola, Jari Ruuska, Esko Juuso and Kauko Leiviskä/ Web Break Sensitivity Indicator, in Proceedings of TOOLMET ’99 Symposium- Tool Environments and Development Methods for Intelligent Systems, Oulu, 1999, pp. 202-209.

Patrik Eklund, Tony Riissanen/ Forest Informatics, IFORS SPC-2 Conference, 25-27 April, 1999, Turku, Finland, pp 26-29.

P. Eklund, J. Zhou, Comparision of learning strategies for parameter identification in rule based systems, J. Fuzzy Sets and Systems, to appear.


11.21 Prediction of electricity consumption

Goals

The opening of National Electricity Stock Market (EL-EX) a few years ago made possible for electricity companies to trade their own production easily with other companies and large-scale consumers. Prediction of future consumption in few next day scale can give a great advantage in both purchasing and selling electricity.

The aim of this project was to study the possibility of predicting consumption in particular distribution area using neural networks. A further aim was to design PC-software based on neural networks to help in the calculation and simulation of different conditions.

The project is still continuing with private financing. The overall aim is to investigate the markets for software and to develop software that provides a convenient tool for estimation of consumption.

Analysis of different neural networks eabled the identification of the optimal network design. However, the difference between the results and realization must be quite small (less than 5 percentage units). The best model so far gave difference of between 0 to 8 % and an average difference of 4.5 %. Considering that consumption in Finland varies very much, result was satisfactory.

Methods

Further information about the software design methods is provided by Tommi Laitinen and neural network design by Ossi Taipale.

Project information

Participant organisations

  • HALT Ohjelmointi Oy, software design, project coordination
  • Taipale Engineering Oy, neural network design
  • Muotoilutoimisto P Haiko, user interface

Project schedule

1.2.1997-31.8.1998

Project volume

FIM 220.000

Project manager

Tommi Laitinen
HALT Ohjelmointi Oy
Perillistenkatu 1
53100 LAPPEENRANTA, Finland
Gsm: +358 40 589 7023
E-mail: tommi.laitinen@halt.net


11.22 Prediction of nozzle clogging - a neural computing approach

Introduction

Clogging of nozzles is a problem metallurgists have been familiar with for a long time. Until today, no definitive solution to the problem has been found.

Typically, nozzle clogging occurs during casting of low silicon aluminium-killed steel grades. A submerged entry nozzle (SEN) is used in transferring liquid steel from the tundish to the mold, in order to eliminate contact between the steel and atmospheric air. The material of SEN is either SiO2 or alumina-graphite, depending on the manganese level of the steel grades. Alumina compounds are usually accumulated at the upper end of the SEN, close to the stopper rod tip, or alternatively at the lower end of the SEN [1].

Figure 1. Areas of nozzle clogging in the SEN [1].

Clogging also occurs when using calcium treatment to improve castability via oxide modification. Precipitation of CaS is a function of the calcium, oxygen and sulphur contents of the steel [1]. Metallurgically, clogging can be avoided, if the inclusions in the steel can be kept liquid during casting, i.e. within a certain chemical composition range. In practice, this has been the method used to prevent clogging.

Imatra Steel

Imatra Steel is a producer of low alloy special steels for European automotive and engineering industries. The product range covers low alloy engineering steel bars, squares, flats and forged vehicle components for motors, transmission and suspension, as well as leaf springs and tubular stabilizer bars.

The melting shop of Imatra Steel Works consists of one 75 tonne electric electric arc furnace, a secondary metallurgy plant, a two-strand bloom caster as well as a reheating furnace for hot bloom charging. The blooms are rolled at a breakdown mill into heavy round bars or billets to be rerolled into round bars and flats.

Imatra Steel’s bloom caster is equipped with a mold level control system which is based on radioactive mold level measurement with Co60and fuzzy logic technology. The system detects on-going clogging of nozzles and starts automatic counter-measures.

Figure 2. Two-strand bloom caster at Imatra Steel.

Study objectives

  1. To test whether neural computing would be applicable to the nozzle clogging problem.
  2. To achieve a better knowledge of process variables affecting to the tendency to clog.
  3. To find effective measures to be taken at a secondary metallurgy facility in order to avoid clogging in individual heats.

Implementation

Retrieval of data

The total amount of different steel grades produced at Imatra Steel is about 300, grouped into ten main families. For this study a production data set for 2000 heats was gathered. The data is resident on the plant’s main database computer. The data was from the year 1997, after commissioning of a new arc furnace. The steel family M-steels (M = steels with improved machinability) is relatively uniform and was therefore selected as a target group for the study.

Selection of process variables for the model

The best neural network model was achieved by selecting the variables based on the steel making expert at the mill. The prediction accuracy advanced significantly compared to the results of mathematical data analysis. The number of the process variables was reduced from 58 down to 8 (Table 1).

Table 1. A list of input variables.

Calcium content
Sulphur content
Soluble aluminium content
Temperature of incoming ladle
Tundish temperature at 1/3 point
Casting speed at 1/3 point
Total aluminium
Liquidus temperature

Two output variables in the neural model were defined; namely clogging in the ladle slide gate and clogging in the SEN.

Data analysis

A careful analysis for the data to be used in the models was carried out. The analysis included mostly manual checking of validity, correction of human errors, removing records which included missing values etc. Thus it was made sure that the conformity in data was at a good level. In several neural computing projects it has been realized that a high quality of data is one of the key issues.

Cluster analysis

The quality of the data for classification was studied using cluster analysis in order to determine whether clear groups could be found. Data distributions between input and output variables were analyzed, both for actual clogging and non-clogging samples.

The analysis confirmed that function fitting probably gives a better model than classification. The clogging phenomen is highly non-linear.

Final model

The final model was based on 311 M-steel heats. Of those, 29 heats were observed to have actual clogging in the SEN area. The training data set consisted of 350 first heats.

Discussion of the results

General models vs single grade models

The correlations were clearly better for a single steel grade data than for a family of grades. This directed the neural network training work for single grade modelling. It was experienced that the best models can be achieved using single grade data. The behaviour from one grade to another was too different to be described in the general grade models. In other words, it was not possible to obtain sufficiently good relationships between the process parameters and the nozzle cloggings.

In data analysis of multigrade the correlations between the input variables, measurements were small. The dependencies between the variables were attenuated each other because of the difference between the behaviour of different grades. When the data analysis and the models were performed for one grade at a time, clear and good results were seen.

Testing of trained neural network

The reliability of the trained neural network was tested by allowing the neural network to predict cloggings, using test data never “seen” by the network. Reliability is measured by the difference between actual cloggings and predicted values.

Based on our experience in this project the "unseen data test" remains best way to see the reliability of the neural network model.

Achievement of goals

  1. Neural network technology can be successfully applied to the nozzle clogging problem.
  2. The prediction capability is at acceptable level for practical purposes, 27 out of 29 cases.
  3. The countermeasures against clogging can be taken at a secondary metallurgy plant.

Future development

A future study is planned to establish the performance of the neural network in comparison to a conventional method. The latter would be based on the actual steel analysis and evaluation of the dominant state of the inclusions in the steel, either solid or liquid, at the casting temperature.

To develop the network further to a production version, an analysis of the role and importance of two of the parameters, tundish temperature and casting speed, is also needed.


11.23 Raw material management from quarry to kiln [IMA Quality Control System (QCS)]

Goals and results

IMA Engineering Ltd Oy  is a global supplier of advanced online xrf -analysers for different types of industrial minerals processing plants.

IMA’s main customer group consists of cement plants and limestone quarries. Typically a cement plant can be considered as a vertically integrated industrial process from mine to ready cement, packed and delivered to final customers. IMA products help cement customers to improve their operations; to make savings in their raw materials handling, and to develop the process. During past 4 years, IMA has focused in developing a distributed online xrf-analyser and a raw material management system for this specific customer group.  This vision or concept includes two different types of online xrf-analyser modules and analysis calculation and specific control software modules, to manage raw material flow from quarry to kiln. This total technical system or concept is called the IMA Quality Control System (QCS).

Figure 1. The IMA distributed raw material management system may have several analysers connected with the same system.

There are two different online xrf-analyser product families: QuarCon Systems 200 and 400 for bulk material analysis from a conveyor belt, and IMACON 10 and 100 Systems for fine raw materials. The software modules include a commercial real-time platform (FIX  from Intellution), the Windows NT operating system and some optional modules. IMA has developed the following software modules: IMACON and QuarCon drivers to integrate 8 analysers in the same system, smart IQCalc analysis and average calculation software (with a Paradox-type open database), IQReporter for easy reporting of instant, average or cumulative results, intelligent RMPCalc Raw Mix Proportioning software to control especially the kiln feed materials, and some tailored calculation and control software.

IMA QCS system architecture and software modules have been developed  step-by-step along with the developments in the two abovementioned analyser families. New features and software modules have been included in new deliveries and occasionally in system upgrades. Development continues and new products or features will be available in coming months or years.

Project information

Participants

Such large scale development has been, and will be, possible only with close cooperation between sub-suppliers, customers or strategic partners. As an example, General Electric R&D has played a key role in RMPCalc fuzzy logic controller design, which eventually led to marketing and sales cooperation with GE Industrial Systems in the USA and Germany.

Project dates

The development of the IMA QCS project started in August 1996 and ended in December 1999 with the current specification.

Project volume

The total cost is several million FIM.

Project manager

Mr Jukka Raatikainen, managing director
Tel. +358 9 8678 100
Fax +358 9 86781020

More information

IMA company and product information is available through their Internet home page: www.ima.fi and in the following publications: Raw Material Management, International Cement Review 5/1998, or Halla Success with IMA, International Cement Review 12/98. Coming soon: Raw Meal Control, World Cement 6/99 and IMACON new tool for Raw Meal Control in International Cement Review 6/99 .


11.24 Software toolkit for design of fuzzy applications in industrial automation

Goals

Fuzzy computing and fuzzy control have potential in various automation tasks where sufficient performance is not achieved with conventional methods. Applications can be, for example, control loops and computing tasks where nonlinear characteristics must be taken into account.

The goal of the project was to develop a software tool for the company. With the tool, feasibility studies of fuzzy computing and the design of fuzzy systems can be carried out in a flexible way. When the software tool has been created, a service package can be developed and marketed for customers.

Results and impacts

The design software makes it possible to create fuzzy systems based on both experts' knowledge and process data by utilizing optimization methods. Different models can be compared and analyzed flexibly with the software.

As of the end of May 1999, the development of the software tool has not been finished. However, the toolkit had already been tested in practice and the results had been promising. Pilot research projects and tests were carried out during the project at two Finnish paper mills.

In future projects, the developed software toolkit will be one of the company's basic tools. Due to increased efficiency that the toolkit provides it is assumed that the productivity of the company will be increasingly improved.

Methods

The software toolkit is developed in the MATLAB environment. Computing functions are integrated into a graphical user interface.

Project information

Participants

Prosessitutkimus H. Peltonen Oy

Project dates

1.8.1998 - 31.12.1999

Project volume

FIM 353.200

Project manager

Heikki Peltonen, DI
Prosessitutkimus Oy
Laserkatu 6
FIN-53850 LAPPEENRANTA; Finland
Tel. +358 5 6243 250
Fax +358 5 4120 949


11.25 Temperature and moisture control of concrete with fuzzy control

Starting status

PCE Engineering is a Finnish engineering corporation, the products of which include concrete technology systems and machines. The production is based on projects and products are customized to meet the needs of the client.

Concrete consists of aggregate material, water and cement. The key factors in producing high quality concrete are the mix design, the finest raw-materials and their accurate dosing and the correct temperature and moisture of the concrete batch. This research project concentrated on finding the correlation between these key factors.

Goals and objectives

The goal of the project was to control concrete temperature and moisture during the manufacturing prosess. The aim was to develop a fuzzy controlling system which keeps the temperature and moisture of a concrete batch stable and constant as required by the operator. The new system calculates the heating times for aggregate silos automatically and gives temperature and moisture estimates for the aggregate materials in the silos. The control system of the baching and mixing plant then calculates the necessary amount of cold and hot water to reach the target temperature and moisture content of concrete.

Results and impacts

The temperature and moisture fuzzy controlling systems developed in this project were tested at an element factory. According to the test results, both temperature and moisture controllability have been improved regardless of the weather conditions and the operator´s experience.

Methods

The fuzzy control systems were applied to the control of the moisture and temperature of concrete. The control systems were developed on the basis of experimental measurements and expert knowledge.

Project figures

Partners

  • Tampere University of Technology

Schedule

The project schedule was orginally from 1.2.1995 to 31.12.1995, but it was extented to 31.12.1996.

Volume

The budget of the project was FIM 1.8 million.

Contact

Mia Kauhanen
Tel. +358 (0)3 549 511
Fax +358 (0)3 549 5300
Email: mia.kauhanen@elematic.com

During Mia Kauhanen´s maternity leave (8.6.1998 – 2.8.1999)

Teemu Mattila
Tel. +358 3 549 511
Fax. +358 3 549 5300
Email: teemu.mattila@elematic.com

11.26 Tool for realising fuzzy control in commercial SCADA systems

Goals

The main goal of this feasibility study was to specify a set of software applications for a flexible fuzzy system environment that could be linked to an existing automation system.

The target was to specify structure and features of this new fuzzy logic software tool having especially following properties:

  • Hardware and software independent as far as possible
  • Ease of use
  • Flexible implementation
  • Versatile and intelligent (adaptive) controller algorithms
  • Easy to tune for various processes
With the help of experienced personnel at the Control Engineering Laboratory, the main features and application tools were specified to achieve the requirements. In addition, some interesting ideas were suggested to strengthen the advantages and minimise the complexity of fuzzy systems.

As a result, a number of variations and requirement specifications were outlined for a new fuzzy logic software tool. The decision about continuing the project will be made later by the company directors.

The first interesting and challenging implementation for the fuzzy control tool was planned to be, for instance, a multivariable and unlinear biotechnical process.

Methods

During the study, it became clear that no individual software development tool could solve the tasks alone. Therefore, the following tools and methods were used in research and test work: Fuzzycon, FuzzEqu & NeurEqu, MatLab, FuzzyTECH and DataEngine.

Project information

Participants

  • Kaarlenkaski Oy
  • University of Oulu, Control Engineering Laboratory

Project dates

1.3.1997 - 9.10.1998

Project volume

FIM 100.000

Project manager

Tapio Myllykoski
E-mail: tapio.myllykoski@kaarlenkaski.fi

More information

Kaarlenkaski Internet homepage:
www.kaarlenkaski.fi


11.27 Use of a neural network to control a separation process

Goals

The goal of this project was to test whether a neural network program is suitable for the simulation and control of the chromatographic separation process. A simulated moving bed process was selected for the application to be tested. Only certain key parameters were selected to be controlled by the neural network model.

Results and impacts

A neural network model was developed to simulate the chromatographic moving bed process of glucose and fructose. The developed neural network model is able to simulate the process by calculating the dry substance profiles based on feed load and on some cycle step volumes. The developed model can be also used for the optimization of parameters based on the target performance.

The model has been tentatively used for offline process optimization. The model is estimating well the parameter changes needed. By using the model it would be possible to achieve an even and improved process performance. No online control or optimization tests have been done. After this Tekes project additional calibration data has been collected. It is obvious, that a neural network model could be used for the mill scale process simulation and optimization also for other chromatographic separation applications.

Methods

To calibrate of the model, mill scale data were collected by using laboratory analyses of the samples and statistical methods for test plans. A neural network model was developed by PC-based Matlab programs to be used by PC. The neural network model was made in cooperation with Taipale Engineering Ltd.

Project information

Participants

  • Cultor Oyj
  • Taipale Engineering Ltd

Project dates

October 1994 – October 1996

Project volume

FIM 441.000

Project manager

Heikki Heikkilä
Cultor Oyj, 02460 Kantvik, Finland


11.28 Use of a neural network in the quality control of particle board production

Goals

The aim of Puhos Board Oy  was to clarify, whether it is possible to improve the quality control of production by using a simulating model based on a neural network.

Detailed goals were:

  • To improve the data collection from the production
  • To find the most important data and also the meaningless data
  • To find out most sensitive parts of the process
  • To find out the best solution in using the existing wood material for different board types 
  • To minimise the cost of changes from one board type to another
  • To have information for changing the process during investments

Results and impacts

During the project the process was analysed carefully and the process knowledge of the personnel increased. Trend analysis has shown a good correlation between the model and measured values. Most of known rules of particle board technology are similar to those suggested in model. New rules have also appeared.

The potential of modelling has been demonstrated and one type of  process modelling system is being put into practice.

Methods

The process was analysed by Puhos Board Oy and VTT. All variables affecting the outcomes of particleboard were included in a database. Data were collected and analysed with the Q-Opt program by Taipale Engineering.

Project information

Participants

Participants of the project, beside Puhos Board Oy, were the Technical Research Centre Of Finland (VTT) and Taipale Engineering Ltd.

Project dates

The project started on 02.01.1997 and ended on 28.2.1999.

Project volume

Total budget of the project was about FIM 1 million.

Project manager

R&D Manager Esa Pesari
Teollisuustie 20 a, FIN-82430 PUHOS, Finland
Tel. +358 13 6823 247
Fax +358-13-6823 249


11.29 Using a neural network for boiler control optimisation; a feasibility study

Goals

The goal of the project was to find out whether it is possible to enhance boiler control by utilising artificial neural networks. The reduction of NOx emissions from the Rauhalahti peat fuelled power plant was set as a specific objective.

Results and impacts

An artificial neural network (NN) model was built in order to determine how the NOx emissions are dependent on the manipulated variables of the boiler.

The evaluation of the results brought up the following facts.

  • The NN model is consistent with the empirical theoretical knowledge in a qualitative sense.
  • Two NN models that are trained using different set of measured data are not always consistent in a quantitative sense. This is obviously due to the large variation in fuel properties, which is common in peat and biofuel power plants.
We conclude that a neural network based combustion model is feasible for NOx reduction in a peat fuelled or bio-fuelled boiler, provided that it is adaptive. The model should adapt to new data in a rather short period of time, for instance, in a few hours, or in a couple of days at the latest. An informative system is probably more feasible than a closed loop system.

Methods

Measured data from the boiler were acquired over several months. The boiler was operated normally throughout this time, and no special experiments were carried out.

A MLP network was created and trained using measured data. The output variable of the network was the NOx content. The input variables were certain manipulated boiler variables (e.g. fuel feed rate, primary airflow and secondary airflow).

The dependencies between the NOx content and the manipulated variables were determined by performing a sensitivity analysis with the model.

Project information

Participants

  • Fortum Power and Heat Oy, formerly Imatran Voima Oy
  • Taipale Engineering Oy

Project dates

Jan 1, 1995 to Dec 31, 1996

Project volume

FIM 150.000

Project manager

Martti Välisuo, M.Sc. (Tech)
Fortum Power and Heat Oy
Technology Centre
P.O. Box 20, FIN-00048 FORTUM, Finland

Publications

Välisuo, Kuoppa, Taipale: Leijupolton optimointi neuroverkkomallin avulla. Automaatiopäivät 1995. (In Finnish.)



jukka.iivarinen@hut.fi
http://www.cis.hut.fi/neuronet/Tekes/11.shtml
Tuesday, 05-Dec-2000 12:56:31 EET