| 1. |
- Birk, Wolfgang, et al.
(author)
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Foam level control in a water model of the LD converter process
- 2001
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In: Automation in mining, mineral, and metal processing 2001. - Oxford : Published for the International Federation of Automatic Control by Pergamon. - 1474-6670. - 0080436927
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Conference paper (peer-reviewed)abstract
- This paper deals with estimation and control of foam level in dynamic foaming. An improved foam level estimation methodology from a microphone signal and its automatic calibration is presented. The dynamical reaction of the foam level on air lance movements is modelled using system identification. Based on the resulting mathematical model, a controller for foam level stabilisation is designed and applied to a water model, representing the LD converter process. It is shown that the foam level can be controlled using a microphone as the measurement device and air lance movement as the actuator.
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| 2. |
- Johansson, Andreas, et al.
(author)
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Nonlinear observer for estimation of metal analysis in steel converters
- 2001
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In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080435602 ; 34:6, s. 1325-1330
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Journal article (peer-reviewed)abstract
- A nonlinear observer whose feedback is weighted by the sensitivity of the output with respect to the state is considered. Conditions for asymptotic stability as well as a region of attraction of the estimation error equation are derived. The results are applied to the problem of metal analysis estimation in a steel converter process
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| 3. |
- Rönnbäck, Sven, et al.
(author)
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A Matlab/Java interface to the MICA wheelchair
- 2004
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In: Elsevier IFAC Publications / IFAC Proceedings series. - Kildington : Elsevier. - 1474-6670. - 0080441718 ; 37:7, s. 93-98
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Journal article (peer-reviewed)abstract
- In the MICA (Mobile Internet Connected Assistant) project a high tech wheelchair has been controlled remotely with MATLAB/Java software client-server implementations. Sensor servers that read, time stamp and store sensor device measurements to databases, runs concurrently on an embedded PC running Linux.The network clients used to read sensor values from the servers are written in Java. That gives them portability between different platforms and architectures.MATLAB client programs runs on stationary computers. These are used to process andvisualize collected data from the wheelchair. MATLAB programs are also used to control and make the wheelchair run semi-autonomously.The combination of MATLAB/Java software is good for fast development, implementation and testing of algorithms in both education and research.With the client/server approach it is possible to have one computer to run a complex and power consuming control algorithm and another one to handle the GUI. Both computers execute MATLAB programs and they run concurrently and have mutual exchange of data over the Internet.When a program works properly in MATLAB it can be ported to Java for faster execution speed and portability.
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| 4. |
- Sololov, Bods M., et al.
(author)
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The Control of the Top Blown Oxygen Converter Process
- 2001
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In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. - 0080435602 ; 34:6, s. 1331-1335
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Journal article (peer-reviewed)abstract
- This paper considers the control of the top blown oxygen converter process by exploiting the static equations of the process in order to compensate for measured disturbances. The dissipation region of the controller is evaluated. A nonlinear observer is introduced for estimating the metal analysis in real time. It is shown that the observer is asymptotically stable and a region of attraction, where the estimation error converges, is derived
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| 5. |
- Stenlund, Benny, et al.
(author)
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Level control of cascade coupled flotation tanks
- 2002
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In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 33:22, s. 185-190
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Journal article (peer-reviewed)abstract
- At the Boliden's concentrator in Aitik, bulk flotation constitutes an important part of the process for extracting valuable minerals from the ore. A series of flotation cells consists of five tanks connected in cascade with control valves between the tanks and a slowly varying flow of mineral slurry into the first tank. This paper deals with a comparative study of control strategies for level control in a flotation series in Aitik. The aim is to show the potential performance improvements taking into account couplings between the process state variables. Two control strategies are considered; a decoupling controller and a linear quadratic (LQ) optimal multivariable controller. Experiments with both structures show a significant enhancement of the level control performance as compared to the original SISO design
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| 6. |
- Stenlund, Benny
(author)
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Supervision of Control Valves in a Series of Cascade Coupled Flotation Tanks
- 2001
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In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 34:27, s. 57-62
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Journal article (peer-reviewed)abstract
- In this paper an algorithm for supervision of control valves in a series of cascade coupled flotation tanks is presented. The benefit of such an algorithm is that it enables monitoring of the plant control system performance and detection of malfunctions in the control valves at an early stage.
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| 7. |
- Tano, Kent T., et al.
(author)
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Feature Extraction of a Strain-Gauge Signal Using Wavelets for Monitoring of a Tumbling Mill
- 2004
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In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 37:15, s. 35-39
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Journal article (peer-reviewed)abstract
- Techniques that measure the force acting on a lifter bar, when it hits the charge inside a tumbling mill, have got an increased interest because of its direct physical relation to the behavior of the grinding charge. The possibility to combine it with discrete element modeling (DEM), which gives an opportunity to visualize the charge motion, opens new possibilities to understand the complex phenomena that takes place inside a grinding mill. In this work, a method for the measurement of the apparent filling level in a pilot ball mill, the Metso Continuous Charge Measurement system (CCM) has been used. The technique uses a strain gauge sensor, mounted on a flat steel spring, which is fitted into a recess underneath a lifter bar. Deflection of the lifter bar during every mill revolution will then give rise to a characteristic signal pattern depending on different operating conditions.In this work, which should be treated as an introduction, we show how the discrete wavelet transform can be used in multivariate calibration. It will be shown that by using the fast wavelet transform on individual signals as a pre-processing method in regression modeling on CCM measurements, good compression is achieved with almost no loss of information. The predictive ability and diagnostics of the data compressed regression model is almost the same as for the uncompressed.
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| 8. |
- Ujvari, Sandor, 1972-, et al.
(author)
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Using simulation for the design of Semi-Autonomous Vehicle systems
- 2001
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In: IFAC Proceedings Volumes. - : Elsevier. - 1474-6670. - 0080435548 ; 33:20, s. 351-356
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Journal article (peer-reviewed)abstract
- The paper describes the development of Semi-Autonomous Vehicles (SAVS) in the context of Automated Guided Vehicle Systems (AGVS). During the design process of a complete material handling AGV-system many variables must be decided. A two-stage simulation approach of discrete event simulation and continuous path simulation, improves development and testing of SAVS, Decisions need to be made e. g. what main navigation sensor to use, how many vehicles are needed for the task. The interrelation of these parameters makes it difficult to find optimum or near-optimum values. Because of this, simulation is a very useful tool to design and evaluate AGV-systems. Copyright (C) 2000 IFAC.
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| 9. |
- Wernersson, Åke
(author)
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Telerobotics : Towards Extending Your Sensing and Hands into a Remote Reality
- 2004
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In: Elsevier IFAC Publications / IFAC Proceedings series. - 1474-6670. ; 37:7, s. 1-4
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Journal article (peer-reviewed)abstract
- The problem addressed is control of robots and/or sensing, in workspaces at remote locations. Topics taken up in this plenary talk includes laser sensing, scene interpretation, telecommands for local autonomy, research issues especially for multirobot systems. Applications includes aerospace testing in north Sweden.Telecommands are studied for high level control of robots over a communication channel with a non-neglectable time delay, time jitters and variable bandwidth. The sensors onboard the robot are a time-of-flight range measuring laser and a video camera. A few images are used by the operator for interpreting the scene. From the interpretations of the workspace around the robot, the operator specifies interactively the sequence of individual operations during a composite task. Each telecommand is then executed autonomously by closing the feedback loop between the robot and the objects in the surrounding workspace.
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| 10. |
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