Output tracking control for class of fuzzy time-delay systems

Dimirovski, Georgi M. (Dogus Author)The output tracking control problem for fuzzy time-delay systems in presence of parameter perturbations has been solved via fuzzy T-S system models and variable-structure control approach. Following the reaching condition, a variable-structure fuzzy control method is proposed accordingly, when the time delay is known and available and when unknown and unavailable. The method guarantees the system operation arrives to the sliding surface in finite time interval and be kept there thereafter while tracking the desired trajectory. The sufficient condition for globally bounded state is derived by using the ISS theory and the LMI method. A simulation example demonstrates the validity and effectiveness of the proposed method.16th Triennial World Congress of International, Federation of Automatic Control, IFAC 200

Observer Design for Takagi-Sugeno Descriptor System with Lipschitz Constraints

This paper investigates the design problem of observers for nonlinear descriptor systems described by Takagi-Sugeno (TS) system; Depending on the available knowledge on the premise variables two cases are considered. First a TS descriptor system with measurables premises variables are proposed. Second, an observer design which satisfying the Lipschitz condition is proposed when the premises variables are unmeasurables. The convergence of the state estimation error is studied using the Lyapunov theory and the stability conditions are given in terms of Linear Matrix Inequalities (LMIs). Examples are included to illustrate those methods.Comment: 13 pages,5 figures; International Journal of Instrumentation and Control Systems (IJICS) Vol.2, No.2, April 201

T-S Fuzzy H∞ Tracking Control of Input Delayed Robotic Manipulators

Time delays are often encountered by practical control systems while they are acquiring, processing, communicating, and sending signals. Time delays may affect the system stability and degrade the control system performance if they are not properly dealt with. Taking the classical robot control problem as an example, the significant effect of time delay on the closed-loop system stability has been highlighted in the bilateral teleoperation, where the communication delay transmitted through a network medium has been received widespread attention and different approaches have been proposed to address this problem (Hokayem and Spong, 2006). In addition, examples like processing delays in visual systems and communication delay between different computers on a single humanoid robot are also main sources that may cause time delays in a robotic control system (Chopra, 2009), and the issue of time delay for robotic systems has been studied through the passivity property. For systems with time delays, both delay dependent and delay independent control strategies have been extensively studied in recent years, see for example (Xu and Lam, 2008) and references therein. For the control of nonlinear time delay systems, model based Takagi- Sugeno (T-S) fuzzy control (Tanaka and Wang, 2001; Feng, 2006; Lin et al., 2007) is regarded as one of the most effective approach because some of linear control theory can be applied directly. Conditions for designing such kinds of controllers are generally expressed as linear matrix inequalities (LMIs) which can be efficiently solved by using most available software like Matlab LMI Toolbox, or bilinear matrix inequalities (BMIs) which could be transferred to LMIs by using algorithms like iteration algorithm or cone complementary linearisation algorithm. From the theoretical point of view, one of the current focus on the control of time delay systems is to develop less conservative approaches so that the controller can stabilise the systems or can achieve the defined control performance under bigger time delay

On-line modeling and control via T-S fuzzy models for nonaffine nonlinear systems using a second type adaptive fuzzy approach

[[abstract]]This paper proposes a novel method for on-line modeling and robust adaptive control via Takagi-Sugeno (T-S) fuzzy models for nonaffine nonlinear systems, with external disturbances. The T-S fuzzy model is established to approximate the nonaffine nonlinear dynamic system in a linearized way. The so-called second type adaptive law is adopted, where not only the consequent part (the weighting factors) of fuzzy implications but also the antecedent part (the membership functions) of fuzzy implications are adjusted. Fuzzy B-spline membership functions (BMFs) are used for on-line tuning. Furthermore, the effect of all the unmodeled dynamics, BMF modeling errors and external disturbances on the tracking error is attenuated by a fuzzy error compensator which is also constructed from the T-S fuzzy model. In this paper, we can prove that the closed-loop system which is controlled by the proposed controller is stable and the tracking error will converge to zero. Three examples are simulated in order to confirm the effectiveness and applicability of the proposed methods in this paper.[[notice]]補正完

A New Approach to Nonlinear Tracking Control Based on Fuzzy Approximation

The problem of tracking control is addressed for a class of nonlinear systems with uncertainties. The original nonlinear systems are approximated by a fuzzy T-S model based on which a state-feedback controller is constructed by using the linear matrix inequalities. The approximating error is eliminated by an adaptive compensator based on fuzzy logic systems. The effectiveness of the proposed control scheme is demonstrated by a simulation example. The main advantage is that the designer makes milder constraint assumption for the approximation error and the uncertainties in nonlinear systems

Optimal Fuzzy Control for a Class of Nonlinear Systems

The paper presents conditions suitable in design giving quadratic performances to stabilizing controllers for given class of continuous-time nonlinear systems, represented by Takagi-Sugeno models. Based on extended Lyapunov function and slack matrices, the design conditions are outlined in the terms of linear matrix inequalities to possess a stable structure closest to LQ performance, if premise variables are measurable. Simulation results illustrate the design procedure and demonstrate the performances of the proposed control design method

Fuzzy Control of Flexible Multibody Spacecraft: A Linear Matrix Inequality Approach

To reduce the cost of lifting to orbit, modern spacecraft and structures used in space applications are designed from light material as flexible multibody system. Moreover The unprecedented requirements for rapid retargeting, precision pointing and tracking capability have made these multibody highly flexible spacecraft vulnerable to dynamic excitation caused by the slewing/pointing maneuver, vibration and external disturbances. As a result, this will degrade the performance of the spacecraft including the pointing accuracy. Thus the aspect of modeling and control become extremely important for the safe and effective operation. Despite the numerous research, the development of high performance, nonlinear control laws for attitude stability, rapid slewing and precision pointing remain the primary objective of scientists and engineers. The aim of the work presented in this thesis is to investigate the stability, performance, and robustness of a class of fuzzy control system called Takagi-Sugeno (T-S) applied to a flexible multi-body spacecraft, and to show the advantage and the simplicity in implementing the T-S fuzzy controller over other baseline nonlinear controllers

Design of Adaptive Fuzzy Controller for Port Cranes

Port STS(ship-to-shore) cranes consist of various complex devices and a length of hoist wire rope. The crane mass changes when loading or unloading containers to/from ships, and disturbances such as waves and wind gusts are also present during crane operations. For these reasons, existing linear controllers cannot achieve the control objective desired by crane operators. This thesis proposes a design for an adaptive fuzzy controller that allows port STS cranes make a trolley follow a target position precisely, while minimizing the swing angle of the containers, even in work environments where changes in parameters and disturbances occur. This thesis introduces a mathematical non-linear system using the Lagrange's equation of motion for the loading and unloading system of a port STS crane. This non-linear system was expressed as nine subsystems, which are also linear systems, and took into account the hoist wire rope length and the container mass. The subsystems were combined with fuzzy rules and implemented with a fuzzy model that had a similar dynamic characteristic to that of a non-linear system. A PI-type state feedback controller (a linear controller) was then designed using a genetic algorithm for each of the subsystems in the fuzzy model. These controllers were then combined with the fuzzy rule again to design the final adaptive fuzzy controller. Compatibility of the proposed fuzzy model is compared with the nonlinear system of the STS crane for port and its effectiveness was verified. Also, The PI type status feedback controller also confirmed its performance. Finally, the proposed adaptive fuzzy controller was applied to the nonlinear system of the port STS cranes, and the validity was verified through computer simulations. In the simulations, changes in reference inputs, applying disturbance, and variation in initial conditions during container loading work where parameters changed were taken into consideration. Under these conditions, the adaptive fuzzy controller performed better than the PI-type state feedback controller. |다양하고 복잡한 장치로 구성되어 있는 항만용 STS 크레인은 컨테이너를 선박에 싣거나 내릴 때마다 호이스트 와이어로프의 길이와 취급하는 컨테이너의 질량이 변하며, 크레인 조종 중 파도와 돌풍 등의 외란도 상존한다. 따라서 기존의 선형제어기로는 크레인이 원하는 제어목적을 달성하기가 어렵다. 본 논문은 이러한 파라미터의 변화와 외란이 존재하는 작업환경에서도 항만용 STS 크레인이 트롤리를 목표위치에 정밀하게 추종시킬 뿐만 아니라 컨테이너의 흔들림을 최소화시킬 수 있는 적응 퍼지제어기 설계기법을 제안한다. 이를 위해, 먼저 항만용 STS 크레인의 하역시스템에 대한 수학적 비선형시스템을 라그랑지 운동방정식을 이용하여 유도하였으며, 이 비선형시스템을 호이스트 와이어로프의 길이와 컨테이너의 질량을 고려하여 9개의 서브시스템, 즉 선형시스템으로 다시 표현하였다. 또한, 이 서브시스템을 퍼지규칙으로 결합하여 비선형시스템과 동역학적 특성이 유사한 퍼지모델로 구현하였다. 다음으로 퍼지모델의 각 서브시스템에 대해 유전알고리즘을 이용하여 PI형 상태피드백제어기(선형제어기)를 설계하였으며, 이들을 다시 퍼지규칙으로 결합하여 최종적으로 적응 퍼지제어기를 설계하였다. 본 논문에서 제안한 퍼지모델의 적합성은 항만용 STS 크레인의 비선형시스템과 비교하여 그 유효성을 검증하였다. 또한, PI형 상태피드백제어기도 그 성능을 확인하였다. 마지막으로 제안한 적응 퍼지제어기를 STS 크레인의 비선형시스템에 적용하고, 컴퓨터 시뮬레이션을 실시하여 그 유효성을 검증하였다. 시뮬레이션은 파라미터가 변화하는 컨테이너 적화작업에서의 기준입력 변화, 외란 인가 및 초기조건 변동 등을 고려하였으며, 이와 같은 환경에서 적응 퍼지제어기는 PI형 상태피드백제어기보다 우수한 성능을 나타내었다.목 차 List of Tables ⅲ List of Figures ⅳ Abstract ⅵ 제 1 장 서론 1 1.1 연구 배경 및 동향 1 1.2 연구 내용 및 구성 3 제 2 장 항만용 크레인의 개요 5 2.1 항만 및 컨테이너 터미널 5 2.1.1 항만 5 2.1.2 컨테이너 터미널 7 2.2 항만용 크레인의 종류 10 2.2.1 STS 크레인 10 2.2.2 트랜스퍼 크레인 11 2.2.3 언로더 13 2.3 항만용 크레인의 주요장치 15 2.3.1 항만용 크레인의 동작장치 15 2.3.2 항만용 크레인의 기계장치 18 제 3 장 항만용 STS 크레인의 모델링 24 3.1 유전알고리즘 24 3.1.1 실수코딩 25 3.1.2 유전연산자 25 3.1.3 적합도 평가 26 3.2 퍼지이론 27 3.2.1 퍼지집합 27 3.2.2 퍼지추론 28 3.3 항만용 STS 크레인의 수학적 모델 31 3.3.1 트롤리부 비선형 모델 31 3.3.2 트롤리 구동부 37 3.3.3 선형화 및 상태공간 해석 39 3.4 항만용 STS 크레인의 퍼지모델 41 3.4.1 퍼지모델링 41 3.4.2 서브시스템 44 3.4.4 퍼지모델의 소속함수 45 제 4 장 항만용 STS 크레인의 제어시스템 설계 47 4.1 상태피드백제어기 설계 47 4.1.1 최적 상태피드백제어기 47 4.1.2 PI형 상태피드백제어기 48 4.2 적응 퍼지제어기 설계 51 제 5 장 시뮬레이션 및 검토 55 5.1 퍼지모델의 적합성 검토 55 5.2 PI형 상태피드백제어기의 성능 검토 70 5.2.1 유전알고리즘을 이용한 피드백 이득 탐색 70 5.2.2 PI형 상태피드백제어기 검토 76 5.3 적응 퍼지제어기의 성능 검토 87 5.3.1 기준입력 변화에 대한 검토 89 5.3.2 외란에 대한 검토 94 5.3.3 초기조건 변동에 대한 검토 103 5.3.4 질량 변화에 대한 검토 107 제 6 장 결 론 112 참고문헌 105Docto

Nuevas perspectivas de la administración

La administración, a partir de la última década, viene recibiendo apoyos muy significativos de las comunidades científicas de su campo; es por ello que el desarrollo de esta disciplina ha trazado líneas importantes de reflexión y ha abierto nuevos espacios para la discusión. Los programas de maestría que se vienen realizando en Colombia se han convertido, sin lugar a dudas, en el espacio donde se han discutido de manera profunda los avances de esta disciplina, donde se han generado nuevas apuestas teóricas, donde se han abierto nuevos esquemas hacia un pensamiento global e integral, donde se ha contrastado de manera más científica la realidad y donde las producciones académicas y científicas han tenido su mayor desarrollo. La administración como disciplina, es en la actualidad un campo importante de las ciencias sociales y humanas; y es desde allí y desde otras perspectivas que esta disciplina sigue avanzado sistemáticamente. La maestría en Administración, de la Facultad de Administración de la Universidad Nacional de Colombia, cuya primera cohorte comenzó en el primer semestre del año 2003, en un esfuerzo valioso de su comunidad académica, se dio a la tarea de realizar una rigurosa selección de los trabajos de investigación que allí se han elaborado, proceso que implicó la consulta a los pares académicos, en virtud de lo cual se escogieron los trabajos que en este libro se presentan; esta ha constituido una labor ardua y además responsable por parte de los investigadores para presentar sus resultados a la comunidad académica