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Model Selection of Hammerstein System Nonlinearity under Heavy Noise

IFAC Proceedings Volumes 2013年第11期46卷 378-383页

作者： Zygmunt Hasiewicz Grzegorz Mzyk Przemysław śliwiński Paweł Wachel Institute of Computer Engineering Control and Robotics Wrocław University of Technology Wybrzeże Wyspiańskiego 27 50-370 Wrocław Poland

The paper deals with the problem of automatic model selection of the nonlinear characteristic in a block-oriented dynamic system. We look for the parametric model of Hammerstein system nonlinearity. From the finite set of candidate classes of parametric models we select the best one on the basis of the input-output measurement data, using the concept of nearest neighbour borrowed from pattern recognitions techniques. The algorithm uses the pattern of the true characteristic generated by its nonparametric estimates on the grid of fixed (e.g. equidistant) points. Each class generates parametrized learning sequence through the values on the same grid of points. Next, for each class, the optimal parameters are computed by the least squares method. Finally, the nearest neighbour approach is applied for the selection of the best model in the mean square sense. The idea is presented on the exemplary competition between polynomial, exponential and piece-wise linear models of the same complexity (i.e. number of parameters needed to be stored in memory). For all classes, the upper bounds of the integrated approximation errors of the true characteristic are computed and compared.

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Correct-by-construction distributed control for multi-vehicle transport systems

Correct-by-construction distributed control for multi-vehicl...

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IEEE International Conference on Automation Science and Engineering (CASE)

作者： Elzbieta Roszkowska Ida Goral Institute of Computer Engineering Control and Robotics Wroclaw University of Technology Poland Department of Electronics Wroclaw University of Technology Poland

In this work we deal with a system of autonomous mobile vehicles with limited communication range and consider the problem of the formally correct distributed control, i.e., the design of the local control for each particular agent so that it ensures globally correct behavior of the system. A particular problem is the fact that the knowledge about the system state possessed by the agents is partial and never accurate, as during the time of information acquisition (by querying other agents) the state of the agents can change. The paper capitalizes on the results of [1] and contributes with: 1) further development of the theoretical idea toward the distributed supervisory control and the concept of robustness, 2) application of the results in the design of a transport agent, and 3) development of a demonstrator, i.e., a computer application that enables the user to specify a considered transport system and its tasks, creates a virtual environment, where each particular vehicle is represented by a particular software agent implementing the control model of (2), and allows observation of the agents concurrent operation and quantitative assessment of the system performance.

关键词： Resource management Vehicles Computational modeling Safety Robustness Protocols Supervisory control

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Multiple shooting SQP-line search algorithm for optimal control of pressure-constrained batch reactor

Multiple shooting SQP-line search algorithm for optimal cont...

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Federated Conference on computer Science and Information Systems (FedCSIS)

作者： Paweł Drąg Krystyn Styczeń Control and Robotics Wroclaw University of Technology Wroclaw Poland Institute of Computer Engineering Wroc Å‚aw University of Technology Wroclaw Poland

In the article a new approach for control of a pressure-constrained batch reactor and a new multi-step optimization algorithm were presented. The considered batch reactor was described by both differential and algebraic equations. State constraints incorporate always difficulties into a mathematical model of the reactor, so a new algorithm based on a multiple shooting SQP-line search method was proposed and tested. The multiple shooting method was used not only to ensure a stability of the solution, but to divide a system into smaller subsystems, so a large-scale problem is considered. The considerations were made for a simultaneous approach, which allows to apply this algorithm to a wide class of differential-algebraic systems. The simulations were executed in Matlab environment using Wroclaw Centre for Networking and Supercomputing.

关键词： Mathematical model Equations Inductors Optimal control Algorithm design and analysis Optimization Trajectory

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Scheduling of composite bridge components transportation in Just In Time system

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IFAC Proceedings Volumes 2013年第9期46卷 2087-2091页

作者： Wojciech Bozdotejko Zdzisław Hejducki Mariusz Uchroński Mieczysław Wodecki Institute of Computer Engineering Control and Robotics Wrocław University of Technology Poland Institute of Construction Wrocław University of Technology Poland Wrocław Centre for Networking and Supercomputing Poland Institute of Computer Science University of Wrocław Poland

This paper presents a mathematical model, the theoretical basis and an outline of a computer module system supporting scheduling of transportation and assembly of composite beam bridge structures implemented in the just in time system (called JIT for short). In the optimization procedures there were used algorithms based on the tabu search method.

关键词： construction project scheduling just in time (JIT) tabu search algorithm

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Computational methods for adaptation of markov models to requested maintenance policies

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computer Modelling and New Technologies 2013年第1期17卷 14-24页

作者： Sugier, J. Wroclaw University of Technology Institute of Computer Engineering Control and Robotics Janiszewskiego St. 11/17 50-372 Wroclaw Poland

State-transition models are often used in reliability analysis and one specific approach of this kind is the subject of this paper. By incorporating elements of both the deterioration process and the maintenance activities (inspections and repairs) in a semi-Markov model, a common computational platform has been created which serves as a foundation for various dependability studies that can investigate different maintenance scenarios. Having available some basic model it is possible to adjust its parameters so that it represents some hypothetical new maintenance policy and then to examine an impact which changing to the new policy has on various reliability characteristics of the system. Particularly, this paper discusses an extension of the generic adjustment algorithm to specific situations of the so-called model saturation when, as a result of tweaking the model towards higher repair frequencies, sum of repairs probabilities in the states reach the maximum value and there is no room for further increase. The general idea is to modify the model in such cases by forcing some non-zero value of a repair probability in those states where it is zero initially but in a manner that will not destroy the overall model behaviour. After theoretical presentation of the modified method its effectiveness is illustrated on practical examples. It is shown that the proposed extension allows to successfully evaluating a class of cases that has not been properly handled by the generic method and thus broadens the range of dependability studies that can be effectively evaluated.

关键词： Repair

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Declarative Approach to AGVS Modeling and Cyclic Scheduling

Declarative Approach to AGVS Modeling and Cyclic Scheduling

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2013 4th International Conference on Information Technology for Manufacturing Systems(ITMS 2013)

作者： Bocewicz Grzegorz Muszyński Wojciech Banaszak Zbigniew Dept. of Electronics and Computer Science Koszalin University of Technology Institute of Computer Engineering Control and Robotics Wroclaw University of Technology Dept. of Business informatics Warsaw University of Technology

The paper presents constraint satisfaction problem driven approach to analytical solution of the cyclic scheduling problem in the Flexible Manufacturing System(FMS) producing multi-type parts where for material handling are used the Automated Guide Vehicles Systems(AGVS). Finding the conditions guaranteeing the AGVs deadlock-free and collision-free movement policy is the aim of our researches. The AGVs co-sharing the common parts of the transportation route while executing repetitive processes, i.e. being assigned to AGVs passing along machines in a cyclic way, can be modeled in terms of Cyclic Concurrent Process Systems(CCPS). Schedulability analysis for a given CCPS answers the question whether a cyclic schedule exists or not. The paper suggests approach for schedulability analysis of multimodal processes representing real manufacturing employing the declarative modeling.

关键词： Discrete event simulation DEVS Environmental science Decision support systems

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Planning with a Task Modeling Framework in Manufacturing robotics

Planning with a Task Modeling Framework in Manufacturing Rob...

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IEEE/RSJ International Conference on Intelligent Robots and Systems

作者： Jacob Huckaby Stavros Vassos Henrik I. Christensen Center for Robotics & Intelligent Machines Georgia Institute of Technology Atlanta GA 30332 USA Department of Computer Control and Management Engineering Sapienza University of Rome 00185 Rome Italy

ISBN: (纸本)9781467363563

In this paper we present the idea that by using AI planning in concert with formal task modeling, the overhead associated with plan creation for complex tasks can be reduced. The proposed approach uses a SysML taxonomy to model the system capabilities and the process specification, and the PDDL planning language to determine acceptable objective solutions. This idea is applied to the manufacturing domain, and examples are shown modeling a multi-robot system in an automobile manufacturing environment. A discussion is given regarding the merits of the demonstrated approach.

关键词： process specification Planning Modeling robotics Automobile manufacture multi-robot systems

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Cyclic scheduling of multimodal processes in mesh-like environment

Cyclic scheduling of multimodal processes in mesh-like envir...

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International Conference on Emerging Technologies and Factory Automation (ETFA)

作者： Grzegorz Bocewicz Wojciech Muszyński Zbigniew Banaszak Department of Computer Science and Management Koszalin University of Technology Koszalin Poland Department of Business Informatics Warsaw University of Technology Warsaw Poland Institute of Computer Engineering Control and Robotics Wrocław University of Technology Wroclaw Poland

A processes composed of sequences of local cyclic The theoretical prediction of the behavioral properties of periodic structures is less difficult than in the case of nonperiodic ones. That is because all the information needed to describe the entire structure is given by the elementary substructure itself and by the manner it repeats in the whole periodic structure. So, only a small portion of the structure (which includes the repeating substructure) needs to be considered to obtain the properties of the whole periodic structure. In that context, the contribution provides the discussion of some system periodicity issues, and is aimed at modeling and evaluation of relationships linking the system structure features with required system's functioning.

关键词： Periodic structures Gears Wheels Transportation Cities and towns Dispatching Job shop scheduling

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Spatio-temporal prediction of collision candidates for static and dynamic objects in monocular image sequences

Spatio-temporal prediction of collision candidates for stati...

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IEEE Symposium on Intelligent Vehicle

作者： Alexander Schaub Darius Burschka Institute of System Dynamics and Control at the Robotics and Mechatronics Center German Aerospace Center Wessling Germany Department of Computer Science Technische Universität München Garching bei Munchen Germany

ISBN: (纸本)9781467327534

This paper presents a novel approach for reactive obstacle avoidance for static and dynamic objects using monocular image sequences. A sparse motion field is calculated by tracking point features using the Kanade-Lucas-Tomasi method. The rotational component of this sparse optical flow due to ego motion of the camera is compensated using motion parameters estimated directly from the images. A robust method for detection of static and dynamic objects in the scene is applied to identify collision candidates. The approach operates entirely in the image space of a monocular camera and does not require any extrinsic information about the configuration of the sensor or speed of the camera. The system prioritizes the detected collision candidates by their time to collision. Additionally, the spatial distribution of the candidates is calculated for non-degenerated conditions. We present the mathematical framework and the experimental validation of the suggested approach on simulated and real-world data.

关键词： Cameras Optical imaging Vectors Robot sensing systems Optical sensors Adaptive optics Collision avoidance

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Underwater Target Positioning with a Single Acoustic Sensor

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IFAC Proceedings Volumes 2013年第33期46卷 233-238页

作者： D. Moreno-Salinas A.M. Pascoal J. Aranda Department of Computer Science and Automatic Control National University Distance Education (UNED) Spain Laboratory of Robotics and Systems in Engineering and Science (LARSyS) Instituto Superior Tecnico (IST) University of Lisbon Portugal Adjunct Scientist National Institute of Oceanography (NIO) Goa India

The availability of reliable underwater positioning systems to localize one or more vehicles simultaneously based on information received on-board a support ship or an autonomous surface vessel is key to the operation of some classes of AUVs. Furthermore, there is considerable interest in reducing the number of sensors involved in acoustic navigation/positioning systems to reduce the costs involved and the time consumed in the deployment, callibration, and recovery phases. Motivated by these considerations, in this paper we address the problem of single underwater target positioning based on measurements of the ranges between the target and a moving sensor at the sea surface, obtained via acoustic ranging devices. In particular, and speaking in loose terms, we are interested in determining the optimal geometric trajectory of the surface sensor that will, in a well defined sense, maximize the range-related information available for underwater target positioning. To this effect, an appropriate Fisher Information Matrix is defined and its determinant is maximized to yield the sensor trajectory that maximizes the accuracy of the target position estimate that can possibly be obtained with any unbiased estimator. It is shown that the optimal trajectory depends on the relative velocity of the sensor, the sampling time between measurements, and the number of measurements acquired for the FIM computation. Simulation examples illustrate the key results derived.

关键词： Autonomous Vehicles Underwater Navigation Optimal Sensor Placement Positioning Fisher Information Matrix Cramer-Rao Bound

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