| 1. |
- Eker, Johan, et al.
(författare)
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A Feedback Scheduler for Real-Time Controller Tasks
- 2000
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Ingår i: Control Engineering Practice. - 0967-0661. ; 8:12, s. 1369-1378
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Tidskriftsartikel (refereegranskat)abstract
- The problem studied in this paper is how to distribute computingresources over a set of realtime control loops in order to optimizethe total control performance. Two subproblems are investigated: howthe control performance depends on the sampling interval, and how arecursive resource allocation optimization routine can be designed.Linear quadratic cost functions are used as performance indicators.Expressions for calculating their dependence on the sampling intervalare given. An optimization routine, called a feedback scheduler, thatuses these expressions is designed.
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| 2. |
- Eker, Johan, et al.
(författare)
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A Flexible Interactive Environment for Embedded Controllers
- 2000
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Ingår i: Control Engineering Practice. - 0967-0661. ; 8:2, s. 139-146
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Tidskriftsartikel (refereegranskat)abstract
- Today embedded control systems are created using tools that give insufficient support for rapid prototyping and code reuse. New tools for the implementation of embedded controllers are necessary. This paper presents the experimental software framework Palsjo, and the language PAL. The Palsjo system is a rapid prototyping environment designed to support on-line system reconfigurations and code reuse. PAL is a new language, designed for the implementation of control algorithms.
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| 3. |
- Gäfvert, Magnus, et al.
(författare)
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Control Of GDI Engines using Torque Feedback Exemplified by Simulations
- 2004
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Ingår i: Control Engineering Practice. - 0967-0661. ; 12:2, s. 165-180
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Tidskriftsartikel (refereegranskat)abstract
- A novel approach to the control of a GDI engine is presented. Thecontroller consists of a combination of subcontrollers, where torquefeedback is a central part. The subcontrollers are with a fewexceptions designed using simple linear feedback and feedforwardcontrol-design methods, in contrast to traditional table-based enginecontrol. A silent extremum-controller is presented. It is used tominimize the fuel consumption in stratified mode. The controller hasbeen evaluated with good results on the European driving cycle using adynamic simulation model.
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| 4. |
- Hägglund, Tore
(författare)
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A Control-Loop Performance Monitor
- 1995
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Ingår i: Control Engineering Practice. - 0967-0661. ; 3:11, s. 1543-1551
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Tidskriftsartikel (refereegranskat)abstract
- A procedure for automatic monitoring of control-loop performance is presented. The control loop performance monitor (CLPM) detects oscillations in the control loop. These oscillations are normally caused by too-high friction in the control valve, but there are other reasons as well. The CLPM is primarily intended to be connected to PID controllers, but it can also be connected to other controllers. The procedure is automatic in the sense that no additional parameters except the normal controller parameters have to be specified. The paper contains both a derivation of the CLPM and results from industrial experiments.
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| 5. |
- Hägglund, Tore
(författare)
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The Blend station - a new ratio control structure
- 2001
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Ingår i: Control Engineering Practice. - 0967-0661. ; 9:11, s. 1215-1220
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Tidskriftsartikel (refereegranskat)abstract
- The paper treats the problem of ratio control. Previous solutionsbased on simple Ratio stations perform poorly during transientscaused by setpoint changes. A new solution, the Blend station, thatimproves control during transients, is proposed. Both a constant-gainand an adaptive version are presented.
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| 6. |
- Ingimundarson, Ari, et al.
(författare)
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Robust tuning procedures of dead-time conpensating controllers
- 2001
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Ingår i: Control Engineering Practice. - 0967-0661. ; 9:11, s. 1195-1208
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes tuning procedures for dead-time compensating controllers (DTC). Both stable and integrating processes are considered. Simple experiments are performed to obtain process models as well as bounds on the allowable bandwidth for stability. The DTC's used have few parameters with clear physical interpretation so that manual tuning is possible. Furthermore, it is shown how the DTC's can be made robust towards dead-time variations.
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| 7. |
- Svantesson, T, et al.
(författare)
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A novel method for mixture viscosity control based on change detection
- 2004
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Ingår i: Control Engineering Practice. - 0967-0661. ; 12:1, s. 11-22
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Tidskriftsartikel (refereegranskat)abstract
- The paper presents a novel method for detecting abrupt changes in mixture viscosities. This problem arises in numerous industrial applications and different solutions are suggested in the literature. An approach of using non-linear filtering for detection-an adaptive filter combined with a change detector-is outlined in this paper. As a case study, we present an ash stabilization batch mixing process used to stabilize a blend of ash/dolomite/water. The main problem is here to predict the quantity of water to be added, since the required amount of water varies with the wood ash quality. One adaptive filter and two change detectors are applied to benchmark data and the detectors are evaluated using basic performance measures. (C) 2002 Elsevier Ltd. All rights reserved.
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| 8. |
- Tunestål, Per, et al.
(författare)
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Cylinder air/fuel ratio estimation using net heat release data
- 2003
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Ingår i: Control Engineering Practice. - 0967-0661. ; 11:3, s. 311-318
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- An estimation model which uses the net heat release profile for estimating the cylinder air/fuel ratio of a spark ignition engine is developed. The net heat release profile is computed from the cylinder pressure trace and quantifies the conversion of chemical energy of the reactants in the charge into thermal energy. The net heat release profile does not take heat- or mass transfer into account. Cycle-averaged air/fuel ratio estimates over a range of engine speeds and loads show an RMS error of 4.1% compared to measurements in the exhaust.
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| 9. |
- Åkesson, Mats, et al.
(författare)
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Probing Control of Fed-batch Cultures: Analysis and Tuning
- 2001
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Ingår i: Control Engineering Practice. - 0967-0661. ; 9:7, s. 709-723
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Tidskriftsartikel (refereegranskat)abstract
- Production of various proteins can today be made using genetically modified Escherichia coli bacteria. In cultivations of E. coli it is important to avoid accumulation of the by-product acetate. Formation of acetate occurs when the specific glucose uptake exceeds a critical value and can be avoided by a proper feeding strategy. A difficulty is that the critical glucose uptake often is poorly known and even time varying. We here analyze an approach for control of glucose feeding that enables feeding at the critical glucose uptake without prior information. The key idea is to superimpose a probing signal to the feed rate in order to obtain information used to determine if the feed rate should be increased or decreased. The main contribution of this paper is to derive guidelines for tuning of the probing controller. A sufficient condition for stability is presented. By introducing proportional and proportional¯integral control action it is possible to improve performance with an unchanged stability guarantee. This also gives a possibility to maintain a minimum specified distance to the critical glucose uptake where acetate formation starts.
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| 10. |
- Åström, Karl Johan, et al.
(författare)
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Automatic Tuning and Adaptation for PID Controllers : A Survey
- 1993
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Ingår i: Control Engineering Practice. - 0967-0661. ; 1:4, s. 699-714
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Tidskriftsartikel (refereegranskat)abstract
- Adaptive techniques such as gain scheduling, automatic tuning and continuous adaptation have been used in industrial single-loop controllers for about ten years. This paper gives a survey of the different adaptive techniques, the underlying process models and control designs. An overview of industrial products is also presented, which includes a fairly detailed investigation of four different adaptive single-loop controllers.
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