| 1. |
- Lessard, Laurent, et al.
(författare)
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Optimal controller synthesis for the decentralized two-player problem with output feedback
- 2012
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Ingår i: American Control Conference (ACC), 2012. - 0743-1619. - 9781457710957 ; , s. 6314-6321
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Konferensbidrag (refereegranskat)abstract
- In this paper, we present a controller synthesis algorithm for a decentralized control problem. We consider an architecture in which there are two interconnected linear subsystems. Both controllers seek to optimize a global quadratic cost, despite having access to different subsets of the available measurements. Many special cases of this problem have previously been solved, most notably the state-feedback case. The generalization to output-feedback is nontrivial, as the classical separation principle does not hold. Herein, we present the first explicit state-space realization for an optimal controller for the general two-player problem.
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| 2. |
- Lewander, Magnus, et al.
(författare)
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Steady state fuel consumption optimization through feedback control of estimated cylinder individual efficiency
- 2012
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Ingår i: Proceedings of the 2012 American Control Conference. - 0743-1619 .- 2378-5861. - 9781457710957 - 9781457710964 ; , s. 4210-4214
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Konferensbidrag (refereegranskat)abstract
- Engine efficiency is often controlled in an indirectway through combustion timing control. This requires a prioriknowledge of where to phase the combustion for differentoperating points and conditions. With cylinder individual efficiencyestimation, control strategies aiming directly at fuelconsumption optimization can be developed. It has previouslybeen shown that indicated efficiency can be estimated using thecylinder pressure trace. This paper presents a method to usethe estimated efficiency as a feedback variable in an extremumseeking control strategy for online steady state fuel consumptionoptimization. The experimental results show that the controllermanages to find the maximum brake torque region at the givenoperating point both with and without external excitation.
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| 3. |
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| 4. |
- Peni, T., et al.
(författare)
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Model recovery anti-windup control for linear discrete time systems with magnitude and rate saturation
- 2012
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Ingår i: American Control Conference. - : IEEE. - 0743-1619. - 9781457710957 ; , s. 1543-1548
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Konferensbidrag (refereegranskat)abstract
- The paper proposes a model recovery anti-windup (MRAW) scheme for linear time-invariant and discrete-time systems under magnitude and rate saturation. The method is a modified, discrete-time counterpart of the algorithm presented in [4]. As it is usual in the MRAW framework the AW compensator contains the exact copy of the plant in order that the ideal (unsaturated) behavior can be preserved in the states. The compensator is a controller that aims to push the plant towards this intended behavior. The design of this control action can be reduced to a construction of a stabilizing state feedback acting on the saturated plant. In [4] this feedback is a linear one, which is designed by convex optimization by enlarging the ellipsoidal approximation of the invariant domain. This paper presents a different, set-theoretic approach, which is based on the precise construction of the maximal control invariant set. The proposed control is a nonlinear one generated by point wise convex optimization.
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| 5. |
- Abdelzaher, Tarek, et al.
(författare)
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Practical Application of Control Theory to Web Services
- 2004
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Ingår i: Proceedings of the American Control Conference. - 0743-1619. ; 3, s. 1992-1997
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Konferensbidrag (refereegranskat)abstract
- This tutorial describes experiences with applying a control theoretical approach to achieving performance guarantees in Web servers, with emphasis on delay control. A model for the server is formulated and translated into a control problem formulation. Limitations of the control theoretic approach are identified that arise due to system non-linearities and modeling inaccuracies. Solutions are proposed that augment the feedback control framework with elements of scheduling and queuing theory. The theoretical results and QoS control loops presented by the authors are implemented in a middleware package, called ControlWare, which provides the software mechanisms and interfaces that allow control of real server performance. Implementation and performance of ControlWare is described.
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| 6. |
- Ali, Mohammad, 1982, et al.
(författare)
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Model-Based Threat Assessment for Lane Guidance Systems
- 2011
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Ingår i: American Control Conference. - 0743-1619. - 9781457700804 ; , s. 4586-4591
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Konferensbidrag (refereegranskat)abstract
- This paper considers a threat assessment problem in a lane guidance application for semi-autonomous vehicles. In particular, in order to issue an autonomous assisting intervention, we assess the vehicle’s ability to safely travel along a path subject to limitations arising from the vehicle’s dynamics and the driver’s ability.We first introduce a set of constraints describing “safedriving”. For the specific lane guidance application considered in this paper, the constraints are set by the lane boundaries and the vehicle’s stability limits. We then formulate the threat assessment problem as a constraints satisfaction problem over a finite time horizon, solved by resorting to reachabililty analysisand invariant set theory.Validation with experimental data demonstrates the capability of the proposed threat assessment method of predicting vehicle instability or crossing of the lane boundaries.
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| 7. |
- Andersson, Alina, et al.
(författare)
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Analytic Parameterization of Stabilizing Controllers for the Surge Subsystem of the Moore-Greitzer Compressor Model
- 2013
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Ingår i: Proc. 2013 American Control Conference (ACC2013). - 0743-1619. - 9781479901777 ; , s. 5257-5262
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Konferensbidrag (refereegranskat)abstract
- This paper is based on a new procedure for dynamic output feedback design for systems with nonlinearities satisfying quadratic constraints. The new procedure is motivated by the challenges of output feedback control design for the 3-state Moore-Greitzer compressor model. First, we use conditions for stability of a transformed system and the associated matching conditions to find the data of the stabilizing controllers for the surge subsystem. Second, using the set of stabilizing controllers satisfying the given constraints for the closed-loop system with the dynamic output feedback controller we made optimization over the parameter set. We present the data of the stabilizing controllers and the new constraints for the corresponding parameters. The contributions in this paper are simplified conditions for the synthesis and optimization over the control parameter set.
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| 8. |
- Aragues, R., et al.
(författare)
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Distributed algebraic connectivity estimation for adaptive event-triggered consensus
- 2012
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Ingår i: American Control Conference (ACC), 2012. - : IEEE. - 9781457710957 ; , s. 32-37
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Konferensbidrag (refereegranskat)abstract
- In several multi agent control problems, the convergence properties and speed of the system depend on the algebraic connectivity of the graph. We discuss a particular event-triggered consensus scenario, and show that the availability of an estimate of the algebraic connectivity could be used for adapting the behavior of the average consensus algorithm. We present a novel distributed algorithm for estimating the algebraic connectivity, that relies on the distributed computation of the powers of matrices. We provide proofs of convergence, convergence rate, and upper and lower bounds at each iteration of the estimated algebraic connectivity.
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| 9. |
- Bao, Lei, et al.
(författare)
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On rate allocation for multiple plants in a networked control system
- 2012
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Ingår i: 2012 American Control Conference (ACC). - : IEEE Computer Society. - 9781457710957 ; , s. 2024-2029
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Konferensbidrag (refereegranskat)abstract
- The problem of allocating communication resources to multiple plants in a networked control system is investigated. In the presence of a shared communication medium, a total transmission rate constraint is imposed. For the purpose of optimizing the rate allocation to the plants over a finite horizon, two objective functions are considered. The first one is a single-objective function, and the second one is a multi-objective function. Because of the difficulty to derive the closed-form expression of these functions, which depend on the instantaneous communication rate, an approximation is proposed by using high-rate quantization theory. It is shown that the approximate objective functions are convex in the region of interest both in the scalar case and in the multi-objective case. This allows to establish a linear control policy given by the classical linear quadratic Gaussian theory as function of the channel. Based on this result, a new complex relation between the control performance and the channel error probability is characterized.
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| 10. |
- Bengtsson, Johan, et al.
(författare)
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Control of Homogeneous Charge Compression Ignition (HCCI) Engine Dynamics
- 2004
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Ingår i: Proceedings of the 2004 American Control Conference, ACC : June 30 - July 2, 2004, Boston Sheraton Hotel, Boston, Massachusetts. - 0743-1619. - 0780383354 ; 5, s. 4048-4053
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Konferensbidrag (refereegranskat)abstract
- The Homogeneous Charge Compression Ignition (HCCI) combustionconcept lacks direct ignition timing control, instead the autoignition depends on the operating condition. Since auto ignition of ahomogeneous mixture is very sensitive to operating conditions, a fastcombustion timing control is necessary for reliable operation. Hence,feedback is needed and the crank angle of 50% burnt (CA50) has provedto be a reliable feedback indicator of on-going combustion inpractice. CA50 or other methods for detecting on-going cylinderpressure used in the feedback control of a HCCI engine all rely onpressure sensors. This paper presents a newcandidate for control of HCCI engine by using the electronicconductive properties in the reaction zone. This phenomenon is calledion current. This paper perform combustion timing control based on ioncurrent and compare it with control based on pressure sensor. Thecombustion timing control is performed on cycle-to-cycle basis and the engine is a one-cylinder version of a heavy duty engine equipped with a port injection system using dual fuels.
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