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Approximating the Time Optimal Solution for Accessible Unknown systems by Learning using a Virtual Output

IFAC Proceedings Volumes 2014年第3期47卷 4140-4145页

作者： Hannes Trogmann Luigi del Re Institute for Design and Control of Mechatronical Systems Johannes Kepler University Linz 4040 Linz Austria

Time optimal control of systems with bounded inputs is a numerically awkward problem as essentially a whole trajectory has to be designed on the basis of a single final point at unknown time. Analytical solutions are possible only for very few problems, in general numerical techniques will be needed, which, in view of the non convexity of the associated optimization problem, will typically converge to a local minimum. In case of an unknown but experimentally accessible nonlinear system, such a solution cannot be found numerically, but a learning algorithm has been proposed which typically converges to a solution not far from the optimal one. However, as in the case of numerical computations, no guarantee of global optimality can be given. In the numerical case, different randomization techniques can be used to ascertain the existence of better solutions, e.g. by choosing different initial conditions. This is more difficult in the case of an experimental method for unknown systems, but this paper proposes an approach based on virtual outputs (linear combination of measurable states) for the same goal which is shown to work in a classical problem of counterintuitive time optimal control - the fastest climbing of a plane.

关键词： Time optimal control aircraft control iterative methods learning control

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control design for a multi input single output hydraulic cylinder system

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IFAC Proceedings Volumes 2014年第3期47卷 10946-10951页

作者： Thomas Schwarzgruber Thomas Ernst Passenbrunner Luigi del Re Institute for Design and Control of mechatronical Systems Johannes Kepler University Linz 4040 Linz Austria

This work discusses several approaches to the multi input, single output problem in hydraulic control. The multi input problem arises from the fact, that the actuator force in a hydraulic cylinder is the result of a combination of two pressure states, which is not uniquely defined. With each individual pressure state there may be associated a subsystem with a control input. To achieve a desired actuator force there are inifinitely many combinations of pressure values possible, and it is therefore unclear how to chose the tracking reference values for the pressure subsystems. Secondary objectives are defined, with time optimality of the step response of the subsystems being one of them, that can be used to solve the multi input problem by treating it as an optimization problem. The practical implications of the optimal solutions are discussed and a new solution is proposed, motivated by the results of the optimization problems. The proposed solution is used to develop a backstepping control for a hydraulic multi input single output system, and its performance is shown in simulation.

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A PCA-based Modeling Approach for Estimation of Road-tire Forces by In-tire Accelerometers

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IFAC Proceedings Volumes 2014年第3期47卷 12029-12034页

作者： David Krier Gabriele S. Zanardo Luigi del Re Institute for Design and Control of Mechatronical Systems Johannes Kepler University Linz 4040 Linz Austria

The knowledge of the forces acting between tire and road is crucial for modern vehicle control systems. Typically, such forces are estimated on the basis of indirect measurements and rely on complex mathematical models. Sensors embedded in the tire (e.g. accelerometers) offer the possibility of directly reaching the area of the tire-road interaction, and of delivering signals during the wheel rotation. Such signals reflect the tire state and the force exchanged between tire and road. In this paper an innovative approach to estimate such forces is presented. It exploits the signal delivered during the wheel rotation by an accelerometer glued to the inner side of the tire tread. The approach consists in processing the signal by means of the Principal Component Analysis (PCA). The results of experimental activities employing a real vehicle provide evidence to support the feasibility and the soundness of the proposed approach.

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Model based control of human heart rate on a bicycle ergometer

Model based control of human heart rate on a bicycle ergomet...

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European control Conference (ECC)

作者： Thomas Leitner Harald Kirchsteiger Hannes Trogmann Luigi del Re Institute for Design and Control of Mechatronical Systems Johannes Kepler University Linz Linz Austria

ISBN: (纸本)9781479947287

A model based controller which regulates the braking intensity of a bicycle ergometer based on information on the heart-rate and breathing volume of the bicyclist is developed. The control system enables training at a desired heart-rate by automatically adjusting the load. The mathematical model was determined using linear continuous time system identification techniques and can reproduce the behavior of the human subject under aerobic metabolic conditions sufficiently well. Data for identification is obtained through an easy to perform test sequence. A linear quadratic controller is synthesized based on the identified model. Experimental results of one subject show the effectiveness of the developed system.

关键词： Heart rate Training Mathematical model Data models Bicycles Instruments control systems

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A tuning approach for offset-free MPC with conditional reference adaptation 19

A tuning approach for offset-free MPC with conditional refer...

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19th IFAC World Congress on International Federation of Automatic control, IFAC 2014

作者： Waschl, Harald Jørgensen, John Bagterp Huusom, Jakob Kjøbsted Del Re, Luigi Institute for Design and Control of Mechatronical Systems Johannes Kepler University Linz Austria Department of Applied Mathematics and Computer Science Technical University of Denmark Denmark Department of Chemical and Biochemical Engineering Technical University of Denmark Denmark

ISBN: (纸本)9783902823625

Model predictive control has become a widely accepted strategy in industrial applications in the recent years. Often mentioned reasons for the success are the optimization based on a system model, consideration of constraints and an intuitive tuning process. However, as soon as unknown disturbances or model plant mismatch have to be taken into account the tuning effort to achieve offset-free tracking increases. In this work a novel approach for offset-free MPC is presented, which divides the tuning in two steps, the setup of a nominal MPC loop and an external reference adaptation. The inner nominal loop addresses the performance targets in the nominal case, decouples the system and essentially leads to a first order response. The second outer loop enables offset-free tracking in case of unknown disturbances and consists of feedback controllers adapting the reference. Due to the mentioned properties these controllers can be tuned separate and by known guidelines. To address conditions with active input constraints, additionally a conditional reference adaptation scheme is introduced. The tuning strategy is evaluated on a simulated linear Wood-Berry binary distillation column example. © IFAC.

关键词： Predictive control systems

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Constrained Optimal control of Multi-Dynamometer Internal Combustion Engine Test Benches

Constrained Optimal Control of Multi-Dynamometer Internal Co...

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American control Conference

作者： T. E. Passenbrunner L. del Re Institute for Design and Control of Mechatronical Systems Johannes Kepler University Linz 4040 Linz Austria

ISBN: (纸本)9781479932757

Dynamical internal combustion engine test benches are commonly used in automotive development to enforce reproducible operating conditions for testing and calibration. The associated control problem consists in tracking simultaneously speed references and torque references and can be described in terms of a nonlinear optimal control problem. In most cases, only one internal combustion engine and one dynamometer are used, either an electrical dynamometer or a hydrodynamic dynamometer, each offering different advantages. In some cases, a so called tandem configuration is meaningful, using a small electrical load machine for baseline operation and a hydrodynamic dynamometer for peak demands, or vice versa. Due to the asymmetric properties of the hydrodynamic dynamometer, the problem cannot be stated directly in terms of a Hamilton-Bellman-Equation, but needs an extension. This paper presents such a solution based on a nonlinear mapping of the asymmetric input constraints and a dynamic extension to the state of the system and examines the usefulness of such an approach. Measurements at a test bench are used to evaluate the performance of the proposed control approach for typical cases.

关键词： Dynamometer Optimal control nonlinear optimal control Tandem configuration Dynamic Extension

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A Model Based Bolus Calculator for Blood Glucose control in Type 1 Diabetes

A Model Based Bolus Calculator for Blood Glucose Control in ...

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American control Conference

作者： Harald Kirchsteiger Luigi del Re Institute for Design and Control of Mechatronical Systems Johannes Kepler University Linz 4040 Linz Austria

ISBN: (纸本)9781479932757

We propose a model based bolus calculator which, based on an identified model, information on the carbohydrate content of the meals and an initial single glucose measurement, computes the optimal insulin bolus dose in order to minimize the blood glucose deviations. We use a simulation model for identification of models for control and closed-loop simulations. The performance of the proposed bolus calculator is compared with a model predictive control approach which uses continuous glucose information and insulin injection. Both methods achieve comparable performance for some patients while the insulin amount, number of injections and computational complexity is significantly reduced for the bolus calculator.

关键词： Blood Glucose Calculators Type 1 Diabetes Mellitus Subcutaneous injection of insulin Simulation models sugar content Meals complexity classes Injections Model predictive control

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${\rm NO}_{\rm x}$ Estimation in Diesel Engines via In-Cylinder Pressure Measurement

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IEEE Transactions on control systems Technology 2014年第1期22卷 396-403页

作者： Simone Formentin Matteo Corno Harald Waschl Daniel Alberer Sergio M. Savaresi Politecnico di Milano Informazione e Bioingegneria Milano Italy Johannes Kepler University Linz Institute for Design and Control of Mechatronical Systems Linz Austria

Heavy-duty (HD) Diesel engines are designed for on-road and off-road equipment with strongly varying operating conditions. In order to meet emission standards, several combustion control strategies and aftertreatment devices employing actual emission information have been developed. Nitrogen oxides (NOx) emissions are among the most constrained by regulations. In this brief, we present a NOx estimation method based on engine speed and indicated pressure measurement. A principal component analysis is performed to describe the information included in the pressure by means of a limited set of variables and L2 regularization techniques are used to derive a simple and reliable estimator. The proposed strategy is implemented on a real off-road HD Diesel engine and validated on both static and dynamic standard test cycles.

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Optimization and Optimal control in Automotive systems

Optimization and Optimal Control in Automotive Systems

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Optimization and Optimal control in Automotive systems: workshop organized by the Austrian Center of Competence in Mechatronics, ACCM 2013

作者： Waschl, Harald Kolmanovsky, Ilya Steinbuch, Maarten del Re, Luigi Institute for Design and Control of Mechatronical Systems Johannes Kepler University Linz Linz Austria Department of Aerospace Engineering University of Michigan Ann Arbor MI United States Department of Mechanical Engineering Eindhoven University of Technology Eindhoven Netherlands

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LMI-based Online Estimation of a Time-varying Time-delay in Continuous Glucose Measurement Devices

LMI-based Online Estimation of a Time-varying Time-delay in ...

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IEEE Annual Conference on Decision and control

作者： Harald Kirchsteiger Hajrudin Efendic Guido Freckmann Luigi del Re Institute for Design and Control of Mechatronical Systems Johannes Kepler University Linz 4040 Linz Austria Institute for Diabetes-Technology GmbH at Ulm University Germany

ISBN: (纸本)9781467360890

We propose an online method to estimate the time-dependent time-delay of continuous glucose measurement devices. The problem is characterized by one delayed signal which is sampled continuously, and a reference signal which is only available for measurement at (few) irregular time samples. The method makes use of a forgetting function to be able to quickly adapt to changes in the time-delay. A simulation example and the application to blood glucose concentration data obtained from type 1 diabetic subjects, where it is of interest to estimate the time-delay of the continuous glucose measurement device, show the usefulness and effectiveness of the proposed method.

关键词： Delays Estimation Optimization Sugar Biomedical measurement Measurement uncertainty

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