| 1. |
- Bengtsson, Johan, et al.
(författare)
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Modeling of HCCI Engine Combustion for Control Analysis
- 2004
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Ingår i: Proceedings 43rd IEEE Conference on Decision and Control. - 0191-2216. - 0780386825 ; 2, s. 1682-1687
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Konferensbidrag (refereegranskat)abstract
- Operation of homogeneous charge compression ignition (HCCI) enginesare very sensitive to timing variations in the combustion of theair-fuel charge mixture and require precise control of the ignitioninstant to run properly. It is therefore essential to understand thecharacteristics of timing variations under various operatingconditions in order to find suitable control strategies. This paperpresents a first step towards the construction of an HCCI enginemodel aimed at studies on timing control strategies. The goal is to(qualitatively) reproduce the timing effects that may be observed ona real engine. The proposed model includes a lumped chemical kineticmodel for hydrocarbon fuels to predict autoignition. Single-cyclesimulations are compared with experimental results from a realengine to validate the model.
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| 2. |
- Calugi, Francesco, et al.
(författare)
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An Adaptive Observer for Dynamical Ship Position Control Using Vectorial Observer Backstepping
- 2003
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Ingår i: Proceedings. 42nd IEEE Conference on Decision and Control, 2003.. - 0191-2216. - 0780379241 ; 4, s. 3262-3267
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose an adaptive observer for dynamically positioned ships, that can be used together with the controller shown by Fossen and Grovlen, to design an observer-based adaptive control scheme. The resulting closed-loop system is globally asymptotically stable with respect to the ship positions and velocities, and globally stable with respect to adaptation to unknown parameters. A discrete-time approximation scheme is presented.
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| 3. |
- Christiansson, Anna-Karin, 1947-, et al.
(författare)
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Continuous-, discrete- and sampled-data- H∞ˆž control - a unified framework
- 2000
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Ingår i: IEEE Proceedings. - 0191-2216. ; 2, s. 1936-1941
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Tidskriftsartikel (refereegranskat)abstract
- We present a unified and general framework for H∞-control in both continuous time, discrete time and combinations of these. The general result is a hybrid continuous-/discrete-time H∞ˆž-controller. Using a compact hybrid notation, the work shows a close relationship between the continuous-and discrete-time solutions. In fact, the pure continuous and discrete time equations may be obtained as two similar interpretations of the general result. There are no assumptions made on certain system matrices being zero or normalised, e.g. D11 = 0. The method is Riccati equation (RE) based, and it is shown how the continuous REs can be "lifted" into discrete ones reflecting the system behaviour during the period. Typical applications are control of continuous-time or discrete-time periodic systems, as well as multirate and sampled-data control, including mixed continuous and sampled-data measurements.
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| 4. |
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| 5. |
- Henriksson, Dan, et al.
(författare)
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On Dynamic Real-Time Scheduling of Model Predictive Controllers
- 2002
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Ingår i: Proceedings of the 41st IEEE Conference on Decision and Control, 2002. - 0191-2216. - 0780375165 ; 2, s. 1325-1330
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Konferensbidrag (refereegranskat)abstract
- The paper discusses dynamic real-time scheduling in the context ofmodel predictive control (MPC). Dynamic scheduling in this settingis motivated by the highly varying execution times associated withMPC controllers. Premature termination of the optimization algorithmis exploited to trade off prolonged computations versuscomputational delay. A feedback scheduling strategy for multiple MPCcontrollers is also proposed, where the scheduler allocates CPU timeto the tasks according to the current values of the cost functions.Simulated examples show how the overall control performance maybenefit from the application of the proposed schemes.
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| 6. |
- Johansson, Rolf, et al.
(författare)
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Observer-based Strict Positive Real (SPR) Switching Output Feedback Control
- 2004
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Ingår i: 2004 43rd IEEE Conference on Decision and Control (CDC). - 0191-2216. - 0780386825 ; 3, s. 2811-2816
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Konferensbidrag (refereegranskat)abstract
- This paper considers switching output feedback control of linear systems and variablestructure systems. Theory for stability analysis and design for a class of observer-based feedback control systems is presented. It is shown how a circlecriterion approach can be used to design an observerbased state feedback control which yields a closedloop system with speci ed robustness characteristics. The approach is relevant for variable structure system design with preservation of stability when switching feedback control or sliding mode control is introduced in the feedback loop. It is shown that there exists a Lyapunov function valid over the total operating range and this Lyapunov function has also interpretation as a storage function of passivity-based control and a value function of an optimal control problem. The Lyapunov function can be found by solving a Lyapunov equation. Important applications are to be found in hybrid systems with switching control and variable structure systems with high robustness requirements.
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| 7. |
- Johansson, Rolf
(författare)
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System Identification using LQG-Balanced Model Reduction
- 2002
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Ingår i: Proceedings of the 41st IEEE Conference on Decision and Control, 2002. - 0191-2216. - 0780375165 ; 35:1, s. 127-132
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Konferensbidrag (refereegranskat)abstract
- System identification of linear multivariable dy-namic models based on discrete-time data can be performed using a algorithm combining linear regression and LQG-balanced model reduction. The approach is applicable also to unstable system dynamics and it provides balanced models for optimal linear prediction and control.
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| 8. |
- Kolesnichenko, Olga, et al.
(författare)
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Extension of Pozharitsky theorem for partial stabilization of a system with several first integrals
- 2002
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Ingår i: Proceedings of the 41st IEEE Conference on Decision and Control, 2002. - 0191-2216. - 0780375165 ; 3, s. 3512-3517
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Konferensbidrag (refereegranskat)abstract
- The paper is devoted to an extension of one particular fact withintheory of partial stability, the so-called Pozharitsky Theorem,to the case of partial stabilization of nonlinear controlled system.It is shown that under appropriate assumptions partialstabilization of the system based on usage some Lyapunov functionconstructed from first integrals of the unforced system, impliesthat the Lyapunov function of a simplified form also leads toa controller that partially stabilizes the system. The theoreticalresults are illustrated by the problem of partial stabilization ofthe downward equilibrium of the Inertia Wheel Pendulum.
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| 9. |
- Lincoln, Bo, et al.
(författare)
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Jitterbug: A Tool for Analysis of Real-Time Control Performance
- 2002
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Ingår i: Proceedings of the 41st IEEE Conference on Decision and Control. - 0191-2216. - 0780375165 ; 2, s. 1319-1324
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Konferensbidrag (refereegranskat)abstract
- The paper presents Jitterbug, a Matlab-basedtoolbox for real-time control performance analysis. The controlsystem is described using a number of connected continuous-time anddiscrete-time linear systems. The control performance is measured bya continuous-time quadratic cost function. A stochastic executionmodel is used to describe when the different discrete-time systemsare updated during the control period. Building different systemmodels, the tool makes it easy to investigate how controlperformance is affected by e.g. input-output delay, sampling jitter,output jitter, lost samples, period overruns, aborted computations,and jitter compensation.
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| 10. |
- Lincoln, Bo, et al.
(författare)
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Suboptimal dynamic programming with error bounds
- 2002
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Ingår i: Proceedings of the 41st IEEE Conference on Decision and Control, 2002. - 0191-2216. - 0780375165 ; 2, s. 2354-2359
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Konferensbidrag (refereegranskat)abstract
- This paper presents a method to relax Dynamic Programming. The methodmakes it possible to findsuboptimal solutions with known error bounds to hard problems.The bounds are chosen by the user, who can then effectively trade-offbetween solution time and accuracy. Several examples from differentdomains where the method is highly useful are presented.
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