Authors: William M. McEneaney

Abstract: Max-plus methods have been explored for solution of first-order, nonlinear Hamilton-Jacobi-Bellman partial differential equations (HJB PDEs) and corresponding nonlinear control problems. These methods exploit the max-plus linearity of the associated semigroups. Although these methods provide advantages, they still suffer from the curse-of-dimensionality. Here we consider HJB PDEs where the Hamiltonian takes the form of a (pointwise) maximum of linear/quadratic forms. We obtain a numerical method not subject to the curse-of-dimensionality. The method is based on construction of the dual-space semigroup corresponding to the HJB PDE. This dual-space semigroup is constructed from the dual-space semigroups corresponding to the constituent Hamiltonians.

Keywords: partial differential equations,curse-of-dimensionality,dynamic programming,max-plus algebra,Hamilton-Jacobi-Bellman equations

Identifier: 10.3182/20050703-6-CZ-1902.00744

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Kiminao Kogiso; Kenji Hirata

Abstract: This paper demonstrates how to construct a reference governor for which the size of its implemented data can be adjusted with an integer parameter v, ensuring fulfillment of a pointwise-in-time constraint. Using a technique called "blocking," a management method is established that changes the external reference every vTs period, where Ts denotes a sampling period of a constrained system. Constraint fulfillment for an infinite time is achieved by satisfying a terminal condition using a maximal output admissible set. The reference governor is finally obtained with an explicit solution to the convex quadratic programming problem. Simulation and experimental evaluations demonstrate its effectiveness at constraint fulfillment and data compression.

Keywords: constraints,closed-loop,data compression,optimization problems,quadratic programming,discrete-time systems

Identifier: 10.3182/20050703-6-CZ-1902.00902

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Prabhakar R. Pagilla; Nilesh B. Siraskar; Ramamurthy V. Dwivedula

Abstract: A decentralized model reference adaptive controller (MRAC) for a class of large-scale systems with unmatched interconnections is developed in this paper. A new reference model is proposed for the class of large-scale systems considered and a stable decentralized adaptive controller is developed for each subsystem of the large-scale system. It is shown that with the proposed decentralized adaptive controller, the states of the subsystems can asymptotically track the desired reference trajectories. To substantiate the performance of the proposed controller, a large web processing line, which mimics most of the features of an industrial web process line, is considered for experimental study. Extensive experiments were conducted with the proposed decentralized adaptive controller and an often used decentralized industrial PI controller. A representative sample of the comparative experimental results is shown and discussed.

Keywords: decentralized control,adaptive control,large-scale systems,web winding systems,material processing

Identifier: 10.3182/20050703-6-CZ-1902.01559

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: W. A. Kamal; D.-W. Gu; I. Postlethwaite

Abstract: A three dimensional probabilistic approach for the path planning of uninhabited air vehicles (UAVs) is presented. The algorithm can be used in real time because of a low computational load in spite of the fact that it finds a path in three dimensions. The paths are locally optimal and are feasible for the UAV to follow by keeping the turn angle within a certain maximum limit. For this purpose, a relation has been derived that transforms the maximum turn angle into a maximum search angle. The UAVs are prevented from flying at very low altitudes to avoid crashing into the ground. Because of limited fuel, a compromise is made between risk and fuel consumption by limiting the height and search angle.

Keywords: UAV,autonomy,path planning,local minimisation,probabilistic approach

Identifier: 10.3182/20050703-6-CZ-1902.02058

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: R. G. Diaz; S. Aguerre; G. Roldan; M. Basualdo

Abstract: A predictive functional controller (PFC) for closed-loop control of glucose using subcutaneous (SC) tissue and intravenous (IV) glycemia measurement and SC and IV infusion of monomeric insulin analogs was developed and evaluated in a simulation study. This analysis is implemented on a generalized rigorous model which can simulate the interaction between glucose-insulin for Type 1 Diabetes Mellitus (T1DM) or normal subjects. According to the simulation results, stable control is achievable for unknown or variable time delays as well as for slow time variations of the controlled system. Therefore model together with PFC could be an useful tool for developing an extra corporeal artificial pancreas prototype and/or as a decision support technique for defining the proper insulin dosage for each patient and for education purposes. Several simulation results are presented for the sake of comparison with other well known models and predictive control strategies.

Keywords: insulin-glucose model PFC strategy decision support diabetes care

Identifier: 10.3182/20050703-6-CZ-1902.02114

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Marco Casini; Chiara Mocenni; Simone Paoletti; Antonio Vicino

Abstract: The correct management of coastal lagoon areas with anthropic exploitation is a difficult task for local authorities. Socio-economic interests and environment preservation are typically contrasting objectives between which a suitable trade-off must be achieved. The solution of this problem requires the development of interdisciplinary and multicriteria approaches. Motivated by future application to the Lagoon of Sacca di Goro (Italy), this paper proposes the architecture of a Decision Support System (DSS) for the management of coastal lagoon areas characterized by shellfish farming and agriculture. The DSS integrates a dynamic model for scenario simulations, the computation of several indicators for sustainability analysis and an optimization model for optimal resource allocation. Special emphasis is devoted to the definition of the optimization problem, which takes into account both the socio-economic and the environmental aspects. A numerical example shows the features of the proposed DSS.

Keywords: environmental system,lagoon management,optimization problem,decision support system

Identifier: 10.3182/20050703-6-CZ-1902.02182

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: R. Wallin; C.-Y. Kao; A. Hansson

Abstract: Semidefinite programs originating from the Kalman-Yakubovich-Popov lemma are convex optimization problems and there exist polynomial time algorithms that solve them. However, the number of variables is often very large making the computational time extremely long. Algorithms more efficient than general purpose solvers are thus needed. In this paper a generalized Benders decomposition algorithm is applied to the problem to improve efficiency.

Keywords: optimization,decomposition methods,robust control

Identifier: 10.3182/20050703-6-CZ-1902.01022

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Xinping Guan; Fenglei Li; Cailian Chen

Abstract: This paper addresses the criterion of delay-dependent stability for nonlinear systems with time-delays which can be represented by Takagi-Sugeno (T-S) fuzzy model with time-delays. Based on Leibniz-Newton formula, the effect of states and the delay states to the stability is considered to construct a Lyapunov functional and to form some special equations, which facilitate proposing a new delay-dependent stability criterion with less conservatism compared with the existing methods, which breaked through the limit to the varying ratio of time-delay. An illustrative example is presented to demonstrate the validity of the proposed stability criterion.

Keywords: delay-dependent stability,Takagi-Sugeno (T-S) fuzzy system,linear matrix inequality(LMI),leibniz-newton formula

Identifier: 10.3182/20050703-6-CZ-1902.01145

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Naoyuki Hara; Akira Kojima

Abstract: This paper deals with a design method of compensation law for linear constrained systems. By employing singular value decomposition of linear systems, we provide a design method of compensation law which fulfills system constraints. The feature of resulting compensation law is illustrated with numerical examples.

Keywords: constrained systems,feedforward compensation,transient,singular value decomposition,deadbeat control

Identifier: 10.3182/20050703-6-CZ-1902.00552

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Joao Y. Ishihara; Aline F. Bianco; Marco H. Terra

Abstract: This paper proposes a new representation for the predictor estimates recursion and corresponding Riccati equation for discrete-time, time-variant descriptor systems. The introduced "9-block" form for the predictor and Riccati equation presents an interesting simple and symmetric structure, which enable us to treat directly the most general systems where state and measurement noises are correlated.

Keywords: Kalman filtering,predicted estimate,descriptor systems,singular systems,state estimation,discrete-time,Riccati equation

Identifier: 10.3182/20050703-6-CZ-1902.00187

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: E. Rocha Loures; J. C. Pascal

Abstract: This paper presents a diagnosis framework based on a qualitative model of the process. Starting from a dynamic abstraction procedure under a defined operating mode a fuzzy partitioning of the variables evolution is made, defining for each measured or observable variable a number of qualitative states. Then time Fuzzy intervals representing the moment of state change are defined. The process behaviour of the operating mode is represented by Time Fuzzy Petri nets (TFPN) model and its evolution is the consequence of events detection due to the partitioning bounds crossing. According to the membership possibility of an event to the estimated time interval and to fuzzy influence knowledge, it is possible to reason about a fault occurrence. The fuzzy data issue from the TFPN components allows evaluating the causes of the fault or failure mode. A model-based diagnosis of a hybrid system is presented.

Keywords: time fuzzy Petri nets,qualitative modelling,possibility theory,detection,diagnosis,hybrid systems

Identifier: 10.3182/20050703-6-CZ-1902.00294

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Yutaka Saitou; Jun-ichi Imura

Abstract: This paper proposes a novel efficient algorithm for model predictive control (MPC) of input-constrained linear systems. Based on the fact that the problem of MPC is reduced into the problem of calculating the solution trajectory of the discrete-time linear complementarity (D-LC) systems, the proposed algorithm fully exploits the information on the solution of the problem at the previous time step, as like the difference technique used in the calculation of solution trajectories of a dynamical system. It is shown that the proposed algorithm is much more efficient than the other conventional algorithms at a large prediction horizon.

Keywords: prediction control,linear complementarity systems,constrained systems

Identifier: 10.3182/20050703-6-CZ-1902.00918

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Andreas C. Nearchou

Abstract: This paper describes the application of differential evolution algorithm (DEA) to the simple assembly line balancing problem (SALBP). DEA is an evolutionary algorithm similar to a real-coded genetic algorithm for global optimization over continues spaces. The paper is concerned with SALBP type-1 whose objective is to minimize the number of workstations required to manufacture a product in an assembly line within a given fixed cycle time. Extensive experimental work over public benchmarks test problems show the effectiveness of the proposed approach.

Keywords: assembly line balancing,differential evolution,meta-heuristics,manufacturing optimization

Identifier: 10.3182/20050703-6-CZ-1902.01463

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Daniele Carnevale; Salvatore Nicosia; Luca Zaccarian

Abstract: In this paper a new model of hysteresis is described. This new model allows to describe a wider class of rate independent hystereses than the previous Classic and nonlinear Preisach models. The broader area of applicability arises from the relaxation of the minor loops equal chord requirement by introducing a less stringent property SVEC(same-vertexes-equal-chords). The new model allows one to fit n-order transition curves, whereas the former models allow only for fitting of first and second-order transition curves. Due to this fact this new model improves upon existing results. The model structure has been developed to be easily implemented in inverse hysteresis control schemes, widely used for hysteretic systems regulation.

Keywords: hysteresis,transition curve,inverse hysteresis

Identifier: 10.3182/20050703-6-CZ-1902.02165

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Kurt R. Rohloff; Tansu Alpcan; Tamer Basar

Abstract: This paper presents a discrete-event systems approach to the modeling of a packet-switched communication link shared by multiple users for the purpose of end-to-end congestion control. It introduces a discrete-event system model for the interaction between a shared communication link and the users, which captures the behavior that the link users receive acknowledgments for successfully transmitted packets with a delay that is proportional to the level of congestion in the link. An end-to-end congestion control scheme for this system model is presented that uses the concept of an observer from supervisory control theory. The link model and controllers are implemented in both a Java programming language simulation and the NS2 network simulation software for analysis.

Keywords: discrete-event systems,queues,networks,supervisory control,decentralized control systems

Identifier: 10.3182/20050703-6-CZ-1902.00298

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Sahika Genc; Stephane Lafortune

Abstract: A new distributed algorithm for on-line fault detection and isolation of discrete-event systems modeled by Petri nets is presented. The algorithm is applicable to systems modeled in a modular manner by means of place-bordered Petri nets, i.e., Petri nets with common places but distinct transitions. These Petri nets have transition labeled with events; fault events are modeled as transitions labeled with unobservable events. It is assumed that the diagnoser modules are able to communicate in real-time during the diagnostic process. A merge function is defined to combine the individual diagnoser states and recover the complete diagnoser state that would be obtained under a monolithic approach.

Keywords: fault diagnosis,distributed algorithms,Petri nets,software implementation

Identifier: 10.3182/20050703-6-CZ-1902.01436

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: V. Havlena; J. Lu

Abstract: The objective of the talk will be to identify current open problems and trends in plant wide control and demonstrate a solution based on distributed, solution component based architecture for integrated process management, embracing the layers of Advanced Process Control, Real Time Optimisation and Planning 8 Scheduling, in selected application areas. The problems and outlined solutions are intended to stimulate discussion as well as attract more research interest.

Keywords: advanced process control,real time optimisation,planning,scheduling

Identifier: 10.3182/20050703-6-CZ-1902.01462

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Thomas Klute; Norman Weiss; Simon Schulz; Thomas Pfeifer

Abstract: This work presents a soccer robot for the FIRA MiroSot league based on a DSP design instead of the more common microcontroller design to provide more flexibility in the use of the robot. The robot's mechanical and electronical design will be presented along with an overview on its control methods and software. Two additions to the robot - an on-board camera module and a 2.4 GHz radio module - will also be reviewed.

Keywords: robot control,robot navigation,robot vision,control algorithms,systems design

Identifier: 10.3182/20050703-6-CZ-1902.02091

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Li Xie; Valery A. Ugrinovskii; Ian R. Petersen

Abstract: In this paper, we present a duality relationship between regular conditional free energy and regular conditional relative entropy given a sub-σ-algebra. This is achieved by using a relation between the Radon-Nikodym derivative of probability measures and that of regular conditional probability measures. Some properties of the regular conditional relative entropy under consideration are also given. The duality relation can be applied in a finite horizon robust state estimation problem for finite-alphabet hidden Markov models.

Keywords: duality relationship,Radon-Nikodym derivative,regular conditional probability measure,regular conditional relative entropy,sub-sigma-algebra

Identifier: 10.3182/20050703-6-CZ-1902.00394

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Robert Miklosovic; Zhiqiang Gao

Abstract: A new dynamic decoupling method is proposed for controlling complex uncertain systems. Where mathematical modeling is often tedious or inaccurate, the new method uses an unknown input observer (UIO) to estimate and cancel dynamic information in real time. Consequently, controller design and tuning become transparent the number of required model parameters is reduced. A realistic turbofan simulation, Sdeveloped by NASA, is used to demonstrate the new design process and compare its performance with that of a supplied benchmark controller.

Keywords: dynamic decoupling,engine control,multivariable control,robust control,state estimation,state observers,time-varying systems

Identifier: 10.3182/20050703-6-CZ-1902.00489

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Ozkan Karabacak; N. Serap Sengor

Abstract: A model of cortex-basal ganglia-thalamus-cortex loop is presented. Even though the mentioned loop has been proposed to take part in different cognitive processes, the model exploits only the "action selection" function. The analysis of the model is based on the stability analysis of a non-linear dynamical system. Thus a biologically valid model of a cognitive function is given and its analysis is accomplished using system theory tools.

Keywords: dynamic modelling,difference equations,stability analysis,stability domains,discriminators

Identifier: 10.3182/20050703-6-CZ-1902.02148

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: A. Germani; C. Manes; P. Palumbo

Abstract: This work presents a family of polynomial filters for discrete-time nonlinear stochastic systems. These filters can be considered the polynomial version of the well known Extended Kalman Filter. The standard EKF consists in the optimal linear filter applied to the linear approximation of systems. The filters presented in this paper are polynomial filters applied to polynomial approximations of nonlinear systems, and therefore each of them is characterized by a pair of integers: the degree of the system approximation and the degree of the filter. The first filter of the family, the one of order (1,1), coincides with the EKF in the standard form. The implementation of the proposed filters does not require the complete knowledge of the noise distributions, but only the moments up to suitable orders. Numerical simulations show the performances of the filters for some values of the degrees.

Keywords: polynomial methods,stochastic systems,state estimation

Identifier: 10.3182/20050703-6-CZ-1902.00215

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Osamu Kaneko; Shotaro Soma; Takao Fujii

Abstract: This paper provides a new and powerful tuning method of controllers in the two-degree of freedom control scheme in the sense of that we require only one-shot experimental data of the closed loop. The key concept of our method is to use the fictitious reference (From this reason, we refer to our method as fictitious reference iterative tuning (FRIT)). Moreover, by using this tuning method, we also provide a new and powerful identification method in the sense of that we require only one-shot closed experimental data. Finally, we give an experimental result in order to show the validity of the proposed method in this paper.

Keywords: controller parameter tuning,fictitious reference iterative tuning (FRIT),two-degree of freedom control scheme,closed loop system idetification one-shot experiment

Identifier: 10.3182/20050703-6-CZ-1902.00105

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: Mazen Alamir; Fadi Ibrahim; Jean Pierre Corriou

Abstract: A new state feedback scheme is proposed for the control of simulated moving beds with strongly nonlinear isotherms. The proposed scheme offers a unified framework enabling different performance criteria to be improved according to the active production constraints (achieving low cost, improving effciency, respecting deadlines) that may unpredictably change during the production batch. The proposed scheme is illustrated through several examples showing the robustness of the closed-loop behavior against parameter uncertainties as well as its reactivity to changes in the active auxiliary criterion.

Keywords: simulated moving bed,nonlinear predictive control

Identifier: 10.3182/20050703-6-CZ-1902.01585

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005

Authors: G. De Tommasi; F. Piccolo; A. Pironti; F. Sartori

Abstract: JETRT is a framework of real-time software and simulation tools designed to help development of control systems in the JET fusion experiment environment. The main design choice is the complete separation of the target application from the hardware and plant interfaces. This architecture has been designed to maximize the reusability and to standardize the software development cycle of real-time control systems. Thanks to this design choice development costs have been reduced and even non-specialist programmers can easily contribute to a real-time project. JETRT also provides a set of powerful debugging and testing tools, some of them well integrated with the Matlab environment. This feature allows to reduce significantly the time spent on the plant for the commissioning of a new control system.

Keywords: real-time systems,object-oriented design and programming,software tools

Identifier: 10.3182/20050703-6-CZ-1902.01052

Conference: Proceedings of the 16th IFAC World Congress, 2005

Location: , Czech Republic

Start Date: Mon Jul 04 2005 - End Date: Fri Jul 08 2005