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VISUAL SERVOING OF A ROBOT MANIPULATOR USING 3-D INFORMATION FROM HAND-HELD CAMERA MOTION.
No full textDevelopment of multiprocessor-based automatic assembly machine for microelectronic components
No full text
볼록 다각형 불확실성을 갖는 시스템의 관측기 기반 강인 제어 설계
Full text link학위논문 (석사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2015. 2. 서진헌.It is important to consider model uncertainties of systems in practical and realistic engineering applications. Model uncertainties are usually expressed as norm-bounded type or polytopic type. Especially, polytopic uncertain systems are a significant class of control systems from both theoretical and practical standpoints, because many control systems are identified as polytopic uncertain systems. In addition, polytopic uncertainty systems usually describe parametric uncertainty in engineering practice more precisely than the norm-bounded uncertainty. While there have been many research works on the observer-based controller design, most of them dealt with norm bounded uncertain systems. Due to the difficulties for selecting a nominal observer model, the observer-based controller design scheme for polytopic uncertain systems has not been reported yet.
With this background, this thesis contributes to design an observer-based controller not only for regulation problems but also for reference tracking problems for discrete-time systems with the polytopic uncertainties. To this end, the robust controller and observer gains are computed such that all possible controller and observer poles of the uncertain systems are located in the open unit disk of the complex plane. Finally, the observer model is selected in a way that the whole closed-loop system is stable. For the sake of selecting such an observer model, it is first expressed as a convex combination of known models and then the convex combination coefficients are computed by solving bilinear matrix inequalities (BMIs). Unlike the linear matrix ineqaulity (LMI), BMI formulation has some drawbacks such as insufficient computer solvers and difficulties when handling numerical errors. Therefore, we have also presented an alternative algorithm which exploits LMI solver iteratively instead of BMI solver. This algorithm is called iterative linear matrix inequality (ILMI).
We can extend the results into the stability problem of switched systems. Hence, the other topic of the thesis is to analyze the stability condition of switched polytopic uncertain systems. With this analysis, the control synthesis and switching rule for stabilization of switched polytopic uncertain systems are discussed.ABSTRACT i
List of Figures vii
Notation and Symbols viii
1 Introduction 1
1.1 Research Background and Motivation . . . . . . . . . . . . . . . . . 1
1.2 Outline of Thesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Preliminaries 5
2.1 Robust Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Robust Controller Gain Design . . . . . . . . . . . . . . . . . . . . 6
2.3 Stability of the Discrete-time Switched System . . . . . . . . . . . 7
2.4 Relationship Between the Two Problems . . . . . . . . . . . . . . 8
3 Robust Stabilization of Uncertain LTI Systems 9
3.1 Problem Formulation . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 Robust Controller Gain Design . . . . . . . . . . . . . . . . . . . . 10
3.3 Robust Observer Design . . . . . . . . . . . . . . . . . . . . . . . . 11
3.3.1 Observer Gain Design . . . . . . . . . . . . . . . . . . . . . 12
3.3.2 Observer Model ¯ A, ¯B , ¯ C Selection . . . . . . . . . . . . . . . 12
3.3.3 Iterative LMIs for Selecting Oρ . . . . . . . . . . . . . . . . 15
3.4 Analysis of the Closed Loop Stability . . . . . . . . . . . . . . . . . 16
3.5 Numerical Simulation Result . . . . . . . . . . . . . . . . . . . . . 18
3.5.1 Numerical Example 1 . . . . . . . . . . . . . . . . . . . . . 18
3.5.2 Numerical Example 2 . . . . . . . . . . . . . . . . . . . . . 20
4 Robust Tracking of Uncertain LTI Systems 25
4.1 Problem Formulation . . . . . . . . . . . . . . . . . . . . . . . . . . 25
4.2 Robust Tracking Controller Design . . . . . . . . . . . . . . . . . . 26
4.3 Robust Observer Design . . . . . . . . . . . . . . . . . . . . . . . . 28
4.3.1 Robust Observer Gain Design . . . . . . . . . . . . . . . . . 28
4.3.2 Observer Model ¯ A, ¯B , ¯ C Selection . . . . . . . . . . . . . . . 29
4.3.3 Iterative LMIs for selecting Oρ,Oη . . . . . . . . . . . . . . 31
4.3.4 Analysis of Reference Tracking . . . . . . . . . . . . . . . . 32
4.4 Numerical Simulation Result . . . . . . . . . . . . . . . . . . . . . 34
5 Robust Stabilization of Discrete-time Switched Uncertain LTV Systems 39
5.1 Stability Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
5.2 Problem Formulation . . . . . . . . . . . . . . . . . . . . . . . . . . 41
5.3 Observer Based Control Design . . . . . . . . . . . . . . . . . . . . 43
5.4 Numerical Simulation Result . . . . . . . . . . . . . . . . . . . . . 46
6 Conclusion 49
Appendix Introduction to LMIs and BMIs 51
BIBLIOGRAPHY 55
국문초록 59Maste
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
저감도 비집중 준최적 제어기에 관한 연구
No full text학위논문(석사) - 한국과학기술원 : 전기 및 전자공학과, 1982.2, [ iii, 125 p. ]Two types of low sensitivity local suboptimal and stabilizing controllers for large scale systems are suggested; local state-feedback controller and local statefeedback controller with integral action. For this, necessary conditions for obtaining the suboptimal gain matrices of each local state-feedback controller are obtained by a parameter optimization technique, where the controllers minimizes not only the integral of squared sum of the state and control variables but also the integral of squared sum of the state and control sensitivity variables. To show the validity of the result, two examples are illustrated.한국과학기술원 : 전기 및 전자공학과
로보트 매니퓰레이터를 위한 반복 학습 제어 방법에 관한 연구
No full text학위논문(박사) - 한국과학기술원 : 전기 및 전자공학과, 1987.2, [ viii, 120 p. ]In this thesis, a class of iterative learning control systems is investigated, and two different types of learning control methods are presented. In particular, the technique is shown to be usefull for the path control of robot manipulators. Specifically, the plant to be controlled is assumed to be linear and time-varying but also periodic so that the plant dynamics remains the same at each iterative operation. In order to find a control input which makes the system state track the desired trajectory within a given error bound for all time, an iterative learning control method is first proposed which is based on a parameter estimator together with an inverse system model to generate the control signal at each iteration. In particular, the parameter estimation is performed with respect to the domain of discrete iterative sequence of operation with time frozen, not with respect to the usual continuous time domain as done in conventional adaptive control techniques. Also, a convergency proof for the algorithm is given. Then the method is shown to be applicable for the motion control of a robot manipulator via linearized model. Another type of an iterative learning control method is proposed by employing a model algorithmic control together with an inverse system model. The proposed model algorithmic control is utilized with respect to the domain of discrete sequence of operation with time frozen, which is different from the conventional model algorithmic control techniques. Also a sufficient condition for convergency of the method is given and two numerical examples, one for a linear periodic system and one for a two link robot manipulator, are illustrated to show the validities of the second method. It is shown that both of the methods are capable of learning in the sense that the subsequent performance of the system is improved in the next operation with the aid of information of previous operation as well as current process data. Finally, it is further shown th...한국과학기술원 : 전기 및 전자공학과
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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