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IEEE International Joint Symposia on Intelligence and Systems

作者： Gyorfi, JS Wu, CH Northwestern Univ Dept Elect & Comp Engn Evanston IL 60208 USA

ISBN: (纸本)0818685484

A general two-phase coordinated planning and control algorithm is developed to determine optimal motions among obstacles and dynamic objects in a shared environment. The algorithm consists of a two-phase approach: planning a global path for each object subject to the constraints of the workspace and then locally optimizing along each global path to minimize some process dependent cost function. The order in which objects are planned will also affect the overall performance of the system. The algorithm is applied to a simulated surface-mount assembly system. The results show an improvement over other planning and control methods.

关键词： Cooperating robots machine Workplace computer algorithms Control Methods surface-mount assembly System performance Planning machinery

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A data model and design principles for temporal databases with homogeneous and non-homogeneous data

A data model and design principles for temporal databases wi...

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作者： Chongstitvatana, Jaruloj Eamsiri Michigan State University

学位级别：Ph.D.

Existing data models and design principles for temporal databases are based on the assumption that a temporal data is associated with an interval as well as its sub-intervals. This type of temporal data is called homogeneous data. A temporal data which is associated with an interval, but not its sub-intervals, is called a non-homogeneous data. Existing data models cannot capture non-homogeneous data accurately, and the existing design principles are not applicable in temporal databases that contain non-homogeneous data. In this dissertation, the relational data model is extended to support both homogeneous and non-homogeneous data. A design principle which avoids inconsistency in temporal databases, that contain homogeneous data as well as non-homogeneous data, is studied. In the proposed extension of the relational data model, temporal relations are classified into two types; property relations and representative relations. A tuple in a property relation is associated with the valid time and its sub-intervals, while a tuple in a representative relation is associated with only the whole interval of its valid time. Thus, the valid time in a property relation is decomposable, but the valid time in a representative relation is not. Based on this characteristics, the valid time in a property relation and that in a representative relation cannot be used in the same manner. In the extension of relational algebra for temporal relations, the calculation of the valid time in a relation, created by relational operators, is determined by the types of the temporal relations. Thus, it guarantees proper use of the valid time. A type of inconsistency, called P-inconsistency, can occur in temporal databases with homogeneous and non-homogeneous data. A normal form, called P-consistency Normal Form (PCNF), which avoids P-inconsistency, is proposed in this dissertation. PCNF is based on types of attributes, functional dependencies, and property dependencies (P-dependencies), in tempor

关键词： computer algorithms

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A new computer algorithm for the reliable calculation of an ill conditioned van der Mond matrix

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ADVANCES IN ENGINEERING SOFTWARE 1997年第9期28卷 621-623页

作者： Kolysh, A Slonim, M Ben Gurion Univ Negev Dept Elect & Comp Engn IL-84105 Beer Sheva Israel

A new computer algorithm for the reliable calculation of an ill-conditioned van der Mend matrix (VDMM) is presented where the determinant of the VDMM is found by calculation of its miners. Two numerical examples illustrate the method's application. One, where the determinant of a third-order equation is analyzed, gives a simple illustration of the technique. The second, where the order of the equation analyzed is raised to 40, shows the advantages of the proposed method compared to the standard one. (C) 1997 Elsevier Science Limited.

关键词： Determinants computers Conditioning algorithms computer algorithms

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Discrete-time adaptive sliding mode control of a linear system in state-space form

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INTERNATIONAL JOURNAL OF CONTROL 1997年第6期67卷 859-868页

作者： Chan, CY School of Electrical and Electronic Engineering Nanyang Technological University 639798 Block S1 Nanyang Avenue Singapore

A discrete-time adaptive sliding mode controller for linear systems represented by the state space is presented. The controller is developed using the delta operator, which is better for approximating continuous-time systems than the shift operator. The use of the delta model allows the selection of the sliding surface to be similar to that for the continuous-time case. It is shown that the adaptive control algorithm leads to a stable closed-loop system. Simulation results are presented to illustrate the features of the proposed control scheme.

关键词： space configuration shift operator Continuous time systems delta discrete-time Linear system state space computer algorithms Controllers Variable structure systems Delta Slip surfaces Self tuning

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Software visualization for debugging

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COMMUNICATIONS OF THE ACM 1997年第4期40卷 44-54页

作者： Baecker, R DiGiano, C Marcus, A UNIV COLORADO BOULDERCO 80309 AARON MARCUS & ASSOCIATES INC EMERYVILLECA

Software visualization is the systematic and imaginative use of the technology of interactive computer graphics and the disciplines of graphic design, typography, color, cinematography, animation, and sound design to enhance the comprehension of algorithms and computer programs. This article demonstrate that, graphical and auditory representations of programs' are useful in debugging and can enliven and enrich programming as a cognitively accessible multimedia experience. To illustrate these ideas, authors present three visualization approaches -- algorithm animation, typographic source code presentation, and interactive auralization for debugging. The three software visualization approaches described here are useful for debugging. Carefully crafted algorithm animations can show how programs work; enhanced typographic representations can improve the readability and comprehensibility of source code; and an interactive environment can let programmers specify software visualizations, including audio portraits of running programs.

关键词： computer software computer algorithms computer graphics computer-generated imagery Source code (computer science) Debugging in computer science

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System identification for state feedback integral observer control of polymer plastic extrusion

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POLYMER-PLASTICS TECHNOLOGY AND ENGINEERING 1997年第5期36卷 749-775页

作者： Lin, YJ Lee, G Department of Mechanical Engineering University of Akron Akron OH 44325 United States

In this article, the system dynamics of a realistic plastic extrusion process is identified by least squares approximation associated with loss and covariance function criteria applied to a set of experimentally measured data of true single-screw extrusion processes. The system identification yields a third-order mathematical model of the process with a single-input/single-output nature. This modeling approach leads to a reliable and effective system model which facilitates the control design. In designing the control algorithm, the derived dynamic model is formulated in the state-space form to obtain the required Riccati equation. Then, an integral observer control methodology is performed. To reduce the computation time, a program which simulates deterministic model and controller design is proposed. In addition, a steady-state matrix based on the algebraic Riccati equations is utilized to design the controller gain matrices. Finally, the observer design methodology employing the observer characteristic equation corresponding to each system matrix is elaborated. The simulation results show that the two controller output data, namely pressure and temperature responses, track the desired values satisfactorily.

关键词： observational data Polymers and Plastics computational time design control State feedback Riccati equations computer algorithms Simulation results System identification System dynamics extrusion extrusion process controller design

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Design and implementation of digital controllers for smart structures using field programmable gate arrays

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SMART MATERIALS AND STRUCTURES 1997年第5期6卷 559-572页

作者： Kelly, JS Rao, VS Pottinger, HJ Bowman, HC UNIV MISSOURI DEPT ELECT ENGN ROLLA MO 65409 USA UNIV MISSOURI INTELLIGENT SYST CTR ROLLA MO 65409 USA

Implementation issues represent an unfamiliar challenge to most control engineers, and many techniques for controller design ignore these issues outright. Consequently, the design of controllers for smart structural systems usually proceeds without regard for their eventual implementation, thus resulting either in serious performance degradation or in hardware requirements that squander power, complicate integration, and drive up cost. The level of integration assumed by the smart patch further exacerbates these difficulties, and any design inefficiency may render the realization of a single-package sensor-controller-actuator system infeasible. The goal of this research is to automate the controller implementation process and to relieve the design engineer of implementation concerns like quantization, computational efficiency, and device selection. Field programmable gate arrays (FPGA) are specifically targeted as a hardware platform because these devices are highly flexible, power efficient, and reprogrammable. The current study develops an automated implementation sequence that minimizes hardware requirements while maintaining controller performance. Beginning with a state space representation of the controller, the sequence automatically generates a configuration bitstream for a suitable FPGA implementation. MATLAB functions optimize and simulate the control algorithm before translating it into the VHSIC hardware description language (VHDL). These functions improve power efficiency and simplify integration in the final implementation by performing a linear transformation that renders the controller computationally friendly. The transformation favors sparse matrices in order to reduce multiply operations and the hardware necessary to support them;simultaneously, the remaining matrix elements take on values that minimize limit cycles and parameter sensitivity. The proposed controller design methodology is implemented on a simple cantilever beam test structure using

关键词： SENSITIVITY SYSTEMS control engineering Controllers degradation of performance Hardware Platform State-space Representation Field programmable gate arrays controller design Designers computer hardware digital controller computer algorithms Parameter sensitivity

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Optimizing the performance of closed-loop adaptive-optics control systems on the basis of experimentally measured performance data

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JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION 1997年第8期14卷 1975-1987页

作者： Ellerbroek, BL Rhoadarmer, TA UNIV ARIZONA CTR ASTRON ADAPT OPTTUCSONAZ 85721

An experimental method is presented to optimize the control algorithm for a closed-loop adaptive-optics system employed with an astronomical telescope. The technique uses wave-front sensor measurements from an independent scoring sensor to calculate adjustments to the wave-front reconstruction algorithm and the bandwidth of the adaptive-optics control loop that will minimize the residual mean-square phase distortion as measured by this sensor. Specifying the range of possible adjustments defines the class of control algorithms over which system performance will be optimized. In particular, the technique can be used to compute an optimized wave-front reconstruction matrix for use with a prespecified adaptive-optics control-loop bandwidth, optimize the control-loop bandwidth for a given reconstruction matrix, optimize the individual modal control bandwidths for a fixed modal reconstructor, or simultaneously optimize both the wave-front modes and their associated control bandwidths for a fully optimized modal control algorithm. The method applies to closed loop adaptive-optics systems that incorporate one or more natural or laser guide stars and one or more deformable mirrors that are optically conjugate to distinct ranges along the propagation path. Initial experimental results are reported for the case of a hybrid adaptive-optics system incorporating one natural guide star, one laser guide star, and one deformable mirror. These results represent what is to the authors' knowledge the first stable closed-loop operation of an adaptive-optics system using multiple guide stars. (C) 1997 Optical Society of America.

关键词： control ring Sensors travel path Bandwidth control systems computer algorithms adaptive optics deformable mirrors Visual System

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An improved algorithm for solving the economic lot size problem (ELSP): A note

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INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH 1997年第6期35卷 1785-1787页

作者： Ditt, S Kuhn, H UNIV COLOGNE SEMINAR ABWL IBL & PRODUKT WIRTSCHAFTD-50923 COLOGNEGERMANY

This article focuses on a study which presented an improved algorithm for solving the economic lot size problem. S. G. Davis, in his study An improved algorithm for solving the economic lot size problem, presents an algorithm for solving the single-facility, multi-product lot scheduling problem minimizing setup and inventory costs subject to a capacity constraint. The example of the ten-product Bomberger problem, which has already been investigated quite often for over 40 years, indicates that his two-stage procedure can lead to solutions with lower costs than those of earlier analyses in acceptable computation times. The three following modifications of Davis' original idea permit a more a more efficient programming. These modifications are active consideration of setup times in step 3 of stage 1, use of a heap structure in step 3 of stage 1 and direct construction of the optimal solution of model 2b in stage 2. To demonstrate the saving in computation time by the suggested modifications a 100-product problem was created by replacing each of the original products by ten equal products having 10% of the original demand each. The results demonstrate the improvement of the procedure suggested by Davis concerning the computation time.

关键词： ECONOMIC lot size INVENTORY control PRODUCTION control computer algorithms algorithms

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Practical design of a sliding mode controller for pneumatic actuators

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JOURNAL OF DYNAMIC SYSTEMS MEASUREMENT AND CONTROL-TRANSACTIONS OF THE ASME 1997年第4期119卷 666-674页

作者： Pandian, SR Hayakawa, Y Kanazawa, Y Kamoyama, Y Kawamura, S Ritsumeikan Univ Fac Sci & Engn Kusatsu 525 Japan Natl Coll Technol Dept Control Engn Nara 639 Japan

Pneumatic robot manipulators are characterized by high-order, time-variant actuator dynamics, nonlinearities due to compressibility of air;external disturbances such as static and Coulomb friction, and wide range of payload variations. Conventional PID controllers suffer from problems of gain tuning under these conditions. In this paper a new control algorithm is proposed for the position and trajectory control of pneumatic actuators based on the sliding mode control approach. The stability of motion is proved for the case of a linear, time-invariant switching surface. A disadvantage of using sliding mode control for third-and higher-order mechanical systems is the need for acceleration feedback. In this paper to overcome this difficulty we propose the use of differential pressure. The proposed controller is simple, easy to implement, and robust to payload and parametric variations. The effectiveness of the new scheme for position and trajectory control is illustrated by experiments on an industrial piston-driven cylindrical actuator with proportional valves.

关键词： actuators Mechanical systems Payload acceleration feedback trajectory control computer algorithms time-invariant Coulomb friction PROPORTIONAL VALVE Compressibility Pneumatic actuators pneumatic robots Variable structure systems

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