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Approximate optimal control by inverse CLF approach

IFAC-PapersOnLine 2015年第11 11期48卷 286-291页

作者： Rohrweck, Hannes Schwarzgruber, Thomas del Re, Luigi Institute for Design and Control of mechatronical Systems Johannes Kepler University Linz Linz4040 Austria

This paper presents an approach to approximate the solution of the infinite horizon optimal control problem for a class of nonlinear systems. Instead of finding an approximate solution of the Hamilton-Jacobi-Bellman (HJB) equation for a given system and cost functional, a control lyapunov function (CLF) is constructed, that solves an optimal control problem for the same system but for a different and a-priori unknown cost-function. By adapting the CLF in an appropriate way, the inverse cost-function approximates the desired cost-function and therefore the found solution approximates the optimal solution. This approach does not only approximate the solution of the original optimal control problem, but it delivers the exact solution of a similar optimal control problem for the very same system. © 2015

关键词： Inverse problems Cost functions Costs Couplings Lyapunov functions Optimal control systems Approximate solution control Lyapunov function Cost functionals Hamilton Jacobi Bellman equations Infinite horizons Optimal control problem Optimal controls Optimal solutions

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Quasi-optimal energy management of range extender buses in presence of changing traffic conditions

Quasi-optimal energy management of range extender buses in p...

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IEEE Conference on control Technology and Applications (CCTA)

作者： Patrick Schrangl Dominik Moser Peter Langthaler Luigi del Re Institute for Design and Control of Mechatronical Systems Johannes Kepler University Linz Austria Steyr Motors GmbH Steyr Austria

ISBN: (纸本)9781509007561

Buses and other vehicles with regular routes and stop patterns are an important application field for hybrid electric drives. Given initial and final desired state of charge (SOC) of the battery, the optimal distribution of power between both sources, battery and engine, can be computed off-line for a known driving cycle. In the case of a range extender (REX) with an engine switched between two operating points, the solution boils down to a sequence of engine state changes. However, applying this profile to the vehicle under general traffic conditions proves very inefficient, as the required traction power over time will change strongly according to the actual traffic and load situation. Instead, this paper suggests to use a spatial-domain SOC trajectory based on off-line optimization results as reference quantity, for which simulations indicate a smaller sensitivity to varying traffic conditions. The paper shows the a posteriori computation of an energy efficient control sequence as well as an on-line implementation that utilizes model predictive control (MPC) and a short-term prediction of the future power demand. Evaluation is performed using a detailed nonlinear simulation model and real traffic data where the limited loss of optimality due to changes of traffic but also due to the driver's style is confirmed.

关键词： Batteries Engines State of charge Vehicles Computational modeling Generators Optimization

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Deviation analysis of clinical studies as tool to tune and assess performance of diabetes control algorithms

Deviation analysis of clinical studies as tool to tune and a...

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IEEE Conference on control Technology and Applications (CCTA)

作者： Florian Reiterer Matthias Reiter Guido Freckmann Luigi del Re Institute for Design and Control of Mechatronical Systems Johannes Kepler University Linz Linz Austria Forschungsund Entwicklungsgesellschaft mbH University of Ulm Ulm Germany

ISBN: (纸本)9781509007561

Clinical trials are the commonly accepted proofs of validity of therapeutic approaches in most medical fields. In many cases, a therapy approach is defined a priori and administered by medical personnel during the trial. In the case of type 1 diabetes mellitus (T1DM), the therapy approach typically consists in fixing a rule for the intake of insulin and taking the corresponding decisions during the day according to measurements and inputs by the patient, e.g. the expected carbohydrate intake. As clinical trials are expensive and complex to realize, only few variants can be really tested. However, in view of the large number of possible options, it would be very useful to be able to test a larger number of variants. Against this background, recently, several methods have been proposed in the scientific literature to extrapolate the effect of a modified therapy using real measurements as baseline. The key idea of all these methods consists in splitting the measurements into a controllable part and a “disturbance” component, which is assumed to be independent from the control action, i.e. from the insulin delivery. Of course, this splitting depends on the specific model assumptions, and the evaluation results of modified therapies may change according to the specific assumed model. However, as this paper shows at the example of the comparison between a standard and an adaptive bolus calculator, the results seem to become consistent if a large enough, representative dataset is used.

关键词： Insulin Sugar Diabetes Standards Data models Calculators

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Simple direct block-oriented system identification for hydraulic motion control

Simple direct block-oriented system identification for hydra...

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European control Conference (ECC)

作者： Philipp Polterauer Thomas Schwarzgruber Patrick Schrangl David Karlsböck Luigi del Re Institute for Design and Control of Mechatronical Systems Johannes Kepler University of Linz Austria David Karlsböck is with TRUMPF Maschinen Austria GmbH + Co. KG Pasching

Block-oriented system modelling allows to define physically meaningful connection points between logically separated parts of a system. This work presents a class of systems in block oriented structure, which allow to apply a simple way of databased modelling. The definition of the class via a few key properties is given, as well as a suitable identification approach. Afterwards it is shown, that the very common system of a hydraulic motion control with servo pumps fits into this system class and the presented method is applied and verified in a simulation example.

关键词： Motion control Nonlinear dynamical systems Actuators Mathematical model Hydraulic systems Estimation

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Approximate optimal control by inverse CLF approach

Approximate optimal control by inverse CLF approach

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作者： Rohrweck, Hannes Schwarzgruber, Thomas del Re, Luigi Institute for Design and Control of mechatronical Systems Johannes Kepler University Linz Linz4040 Austria

关键词： Cost functions

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Adaptive SCR Model for MPC control Including Aging Effects

Adaptive SCR Model for MPC Control Including Aging Effects

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SAE 2015 World Congress and Exhibition

作者： Stadlbauer, Stephan Waschl, Harald Del Re, Luigi Institute for Design and Control of Mechatronical Systems Johannes Kepler University Linz Altenbergerstr. 69 LinzA-4040 Austria

The focus in the development of modern exhaust after treatment systems, like the Diesel Oxidation Catalyst (DOC), the Diesel Particulate Filter (DPF) and Selective Catalytic Reduction (SCR), is to increase on one hand the oxidation rates of Carbon monoxide (CO), HC (Hydro Carbons) and NO (Nitrogen Oxide) and on the other hand the reduction rates of Particulate Matter (PM) and the NOx emissions to fulfill the more and more restricting requirements of the exhaust emission legislation. The simplest, practical most relevant way to obtain such a dosing strategy of a SCR system is the use of a nonlinear map, which has to be determined by extensive calibration efforts. This feedforward action has the advantage of not requiring a downstream NOx sensor and can achieve high conversion efficiency under steady-state operating conditions for nominal systems. However, such an open-loop approach leads to suboptimal conversion efficiency during transient operation condition and in the presence of system variations (e.g. aging, doser variation). Hence, feedback information and an adaptation criterion for an appropriate SCR life time control is an essential feature to achieve the demanding legislation limits. Against this background, this proposal presents an ammonia dosing control by an adaptive model predictive controller. The proposed SCR-model estimates the surface coverage of the SCR and the controller calculates the appropriate Adblue dosing. To address variations due to a model/plant mismatch, caused by aging effects an adaptive identification of the model is proposed. To avoid a complex additional identification and required excitation, only a few adaptation parameters, mainly responsible for the aging effects of the SCR are identified. Finally this approach is compared to the nominal dosing for a SCR in simulation. The purpose is to underline the advantages of such an easy adaptable approach concerning a balanced NH3 slip and NOx reduction for aged SCR converters. Copyright

关键词： Selective catalytic reduction

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Improving the transient emission performance of a Diesel engine by input shaping techniques

Improving the transient emission performance of a Diesel eng...

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The Society of Instrument and control Engineers Annual Conference 2015

作者： Roman Schmied Stephan Stadlbauer Harald Waschl Luigi del Re Institute for Design and Control of Mechatronical Systems Johannes Kepler University

Caused by the demanding and more and more stringent legislated emission limits for passenger car engines,the effect of transient emission peaks becomes more and more important for the overall emission limits. In case of Diesel engines, the two main concerned pollutants are NOx and PM and typically the compliance with the legislation is achieved by a suitable control of the fuel and air system of the engine. Especially during transients the coordination of both loops is crucial for the overall performance. Typically the control is separated in the two loops, where coupling effects and different time scales and dynamics can lead to undesired overshoots during transients. Against this background in this work an input shaping technique to reduce the transient emission peaks is proposed. The input shaping is based on an identified response model of the transient emission profile and used to determine suitable correction trajectories which can be applied to an existing calibration and reduce undesired effects during transients while allowing to keep the base calibration and control structure of the engine control unit. In this study input shaping is applied for the rail pressure and injection parameters to reduce the NOx emissions while the PM emissions, efficiency and noise levels should be kept similar to the nominal operation. The proposed strategy is evaluated on a 2l turbocharged common rail passenger car Diesel engine mounted at a dynamic engine testbench and promising results are achieved.

关键词： Diesel engine,input shaping,transient emission reduction

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Validation of a virtual control oriented cylinder selective soot sensor

Validation of a virtual control oriented cylinder selective ...

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The Society of Instrument and control Engineers Annual Conference 2015

作者： Zhen Zhang Stephan Stadlbauer Richard Fuerhapter Luigi del Re Institute for Design and Control of Mechatronical Systems Johannes Kepler University

The improved steady state performance of engine control and aftertreatment makes the transient contribution to the total emissions increasingly important. As several control mechanism, e.g. the exhaust recirculation, are set for all cylinders at a time, misbalancing represents a practical limit to the achievable emission control. This paper tackles both issues at a time using a virtual soot sensor. The virtual soot sensor is based on piecewise principal components analysis(PCA) of the in-cylinder pressure measurements and on their representation by a polynomial structure which has been proposed in a previous work. The peaks detected by sensor during transient working condition cannot be confirmed as standard PM or soot measurement systems are too slow. In this paper we use an in-situ laser induced incandescence(LII)system to provide a fast soot reference and to validate the performance of the virtual soot sensor. The results confirm the ability of the proposed virtual sensor to recognize soot changes- also between individual cylinders- with sufficient speed without requiring any additional hardware.

关键词： Particulate Matter,Soot model,Transient emission,Fast soot measurement,LII

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Approximate optimal control of discrete I/O systems with C/GMRES

Approximate optimal control of discrete I/O systems with C/G...

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European control Conference (ECC)

作者： J. Blumenschein T. Schwarzgruber R. Schmied T. E. Passenbrunner H. Waschl L. del Re Master thesis at the Institute for Design and Control of Mechatronical Systems Johannes Kepler University Linz Linz Austria Institute for Design and Control of Mechatronical Systems Johannes Kepler University Linz Linz Austria

This paper proposes an optimal control approach to control systems described by discrete time I/O models. In particular, the C/GMRES method, which is a curse-of-dimensionality free and fast approximative optimal control method is adapted to this purpose. Comparing this approach with conventional industry standard methods, the benefits are twofold: First, easy and intuitive tuning of the control via the quadratic cost function of the optimization problem, reducing the necessary parameterization and tuning effort typical in industrial applications. Second, direct use of discrete time I/O models, typically the result of data based modeling efforts, which themselves can reduce development time drastically, compared to classical first principles and parameterization methods. To demonstrate the possible advantages of this method, it is applied to a problem, where tedious control parametrization and the resulting tuning efforts are state of the art: The control of the Diesel engine airpath is a MIMO system tracking problem, where the achieved tracking error of the outputs are decisive of the main emissions of the Diesel engine.

关键词： Optimal control Mathematical model Tuning Adaptation models Aerospace electronics Optimization

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Improving the transient emission performance of a Diesel engine by input shaping techniques

Improving the transient emission performance of a Diesel eng...

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Conference of the Society of Instrument and control Engineers of Japan

作者： Roman Schmied Stephan Stadlbauer Harald Waschl Luigi del Re Institute for Design and Control of Mechatronical Systems Johannes Kepler University Linz Austria

ISBN: (纸本)9781479985845

Caused by the demanding and more and more stringent legislated emission limits for passenger car engines, the effect of transient emission peaks becomes more and more important for the overall emission limits. In case of Diesel engines, the two main concerned pollutants are NOx and PM and typically the compliance with the legislation is achieved by a suitable control of the fuel and air system of the engine. Especially during transients the coordination of both loops is crucial for the overall performance. Typically the control is separated in the two loops, where coupling effects and different time scales and dynamics can lead to undesired overshoots during transients. Against this background in this work an input shaping technique to reduce the transient emission peaks is proposed. The input shaping is based on an identified response model of the transient emission profile and used to determine suitable correction trajectories which can be applied to an existing calibration and reduce undesired effects during transients while allowing to keep the base calibration and control structure of the engine control unit. In this study input shaping is applied for the rail pressure and injection parameters to reduce the NOx emissions while the PM emissions, efficiency and noise levels should be kept similar to the nominal operation. The proposed strategy is evaluated on a 21 turbocharged common rail passenger car Diesel engine mounted at a dynamic engine testbench and promising results are achieved.

关键词： Diesel engine input shaping transient emission reduction

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