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This paper initially proposes an optimization problem and after presents its optimal solution. Then, this result is applied to obtain relaxed conditions to design controllers for nonlinear plants described by Takagi-Sugeno (TS) models, based on fuzzy Lyapunov function (FLF) and Linear Matrix Inequalities (LMI). The FLF is given by $V(x(t)) = x(t)^{T}P(\alpha (x(t)))x(t)$ , where $x(t)$ is the plant state vector, $P(\alpha (x(t))) = \alpha _{1}(x(t))P_{1} + \alpha _{2}(x(t))P_{2} + \cdots + \alpha _{r}(x(t))P_{r}$ , $P_{i}=P_{i}^{T} > 0$ and $\alpha _{i}(x(t))$ is the weight related to the local model $i$ in the representation of the plant by TS fuzzy models, for $i=1,2,\cdots,r$ . When one calculates the time derivative of this $V(x(t))$ , it appears the term $x(t)^{T}\dot {P}(\alpha (x(t)))x(t)$ , that is usually handled using conservative upper bounds, supposing that the bounds of the time derivative of $\alpha _{i}(x(t))$ , $i=1,2,\cdots,r$ , are available. The main result of this paper is a procedure to obtain optimal upper bounds for the term $x(t)^{T}\dot {P}(\alpha (x(t)))x(t)$ , such that they contemplate the maximum value and are always smaller than or equal to the maximum value. It is a relevant result on this subject, because these optimal upper bounds do not add any constraint. With these optimal upper bounds, a relaxed design method for stabilization of TS fuzzy models is proposed. Two numerical examples illustrate the effectiveness of this procedure.

This paper presents the design of a state observer-based output feedback controller applied to a discrete-time coupled inductors Cuk converter. The anti-windup concept is employed in the design of the final controller in order to guarantee an adequate dynamic performance against the saturation effect at the control input. Finally, simulation results are presented in order to validate the effectiveness of the proposed control system.

Made available in DSpace on 2021-06-25T10:22:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) An experimental study is discussed on a strategy that combines on-off and sliding mode control to swing up and control a pendulum with two reaction wheels in the upright position. The control scheme uses only one reaction wheel at a time, adapting the control law to turn off one of the control actions. The design takes into account the plant limitations, thus justifying the combination of the two strategies. The mechanical differences between the standard reaction wheel pendulum configuration and the one studied in this paper are pointed out to explain the use and the operation of the controller. Additionally, two cases are studied to verify experimentally the performance of the controller designed using low-cost hardware for real-time tests. Department of Mechanical Engineering São Paulo State University (UNESP), Avenida Brasil 56 Department of Aerospace Engineering Sciences University of Colorado Department of Electrical Engineering São Paulo State University (UNESP), Avenida Brasil 56 Department of Mechanical Engineering São Paulo State University (UNESP), Avenida Brasil 56 Department of Electrical Engineering São Paulo State University (UNESP), Avenida Brasil 56 FAPESP: 2018/13751-8 CNPq: 306526/2019-0

Este artigo apresenta o projeto de um controlador fuzzy Takagi-Sugeno para o conversor Cuk bidirecional aplicado à carga e descarga de uma bateria. A bateria é modelada através de um modelo elétrico de segunda ordem. A técnica de modelagem, por valores médios em espaço de estados, é aplicada aos modos Buck e Boost do conversor Cuk, operando em modo de condução contínua (MCC). Do modelo por valores médios, em espaço de estados, um modelo fuzzy T-S do conversor Cuk bidirecional é derivado. O conceito de compensação distribuída paralela (CDP) é utilizado para a obtenção de uma lei de controle fuzzy integral do conversor, no qual os ganhos de retroalimentação são obtidos através da resolução de um problema de desigualdades matriciais lineares (DMLs). A saturação da entrada de controle do conversor é considerada na análise de estabilidade do sistema em malha fechada. Além disso, o critério de desempenho

Made available in DSpace on 2020-12-12T02:05:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Reaction wheels have been extensively used to control and stabilize a wide range of applications due to the angular momentum exchange that they provide to mechanical systems. However, there exist several limitations associated with actuator saturation and the presence of singularities that lead towards the use of different controllers and devices. Recently, a new and unusual configuration using two reaction wheels was proposed and illustrated in an inverted pendulum to drive and control it using a simple and well-known PID controller. In this context, this paper improves the previous results on the same system by proposing two more sophisticated nonlinear controllers: a nonlinear proportional-derivative and a sliding mode controller. The proof of the stability of each controller is also provided, and the asymptotic stability is proven. A friction model is experimentally updated into the differential equations of the pendulum and also included for the controllers designing. A real-time application verifies the performance of the controllers using low-cost hardware. Results based on the analysis of different performance indices highlight the improvement of applying these two nonlinear control techniques comparing to the previous paper using this configuration of actuators. Departamento de Engenharia Mecânica Faculdade de Engenharia de Ilha Solteira Universidade Estadual Paulista (UNESP) Departamento de Engenharia Elétrica Faculdade de Engenharia de Ilha Solteira Universidade Estadual Paulista (UNESP) Department of Aerospace Engineering Sciences Colorado Center for Astrodynamics Research University of Colorado Boulder Departamento de Engenharia Mecânica Faculdade de Engenharia de Ilha Solteira Universidade Estadual Paulista (UNESP) Departamento de Engenharia Elétrica Faculdade de Engenharia de Ilha Solteira Universidade Estadual Paulista (UNESP)

Made available in DSpace on 2019-10-06T16:38:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 The attitude control using reaction wheels as actuators has been one of the most popular ways to stabilize and repel external disturbances in aerospace devices. From the controlled change of the angular momentum rate of change using reaction wheels, it is possible to control the oscillation and direction rates of change of rigid bodies in space. Thus, the main idea of this article is to present a case study with different configurations of the well-known reaction wheel pendulum. The first is based on the classical configuration, and the second, a new one, a pendulum with two reaction wheels. For both configurations, proportional–integral–derivative controllers were designed and experimental devices were built to perform real-time controllers using low-cost hardware. The simulated and experimental results have shown that the pendulums were controlled using a simple controller in the inverted position and the results were satisfactory. Four performance indices were calculated to evaluate the results for each configuration. They showed that the pendulum with two reaction wheels worked better than the pendulum with one reaction wheel. Two actuators made it easier to move and control the pendulum in the inverted position. Departamento de Engenharia Mecânica Faculdade de Engenharia de Ilha Solteira UNESP—Universidade Estadual Paulista Departamento de Engenharia Elétrica Faculdade de Engenharia de Ilha Solteira UNESP—Universidade Estadual Paulista Departamento de Engenharia Mecânica Faculdade de Engenharia de Ilha Solteira UNESP—Universidade Estadual Paulista Departamento de Engenharia Elétrica Faculdade de Engenharia de Ilha Solteira UNESP—Universidade Estadual Paulista

This paper is concerned with the design of variable structure controllers for uncertain switched linear plants. The proposed method is based on Lyapunov-Metzler inequalities and on properties of strictly positive real SPR systems, with the advantage that it can be applied in control of uncertain switched linear system. The first contribution shows that there exists a solution of the SPR synthesis for a class of linear uncertain switched systems using switched static output feedback, if and only if there exists a solution of this SPR synthesis with switched static state feedback. This result is a generalization of known conditions regarding this problem, for linear time-invariant and known without uncertainties plants, and offers a possible procedure for output feedback SPR synthesis: first solve the state feedback SPR synthesis and then, using the obtained solution, find a solution for the output feedback SPR synthesis. Next are presented necessary and sufficient sufficient conditions for the SPR synthesis for a class of linear uncertain switched systems using switched static output feedback, for plants with the same number of inputs and outputs with the number of outputs greater than the number of inputs. Two examples illustrate the effectiveness of the robust control system, including applications of the proposed methods, considering switched static state feedback and switched static output feedback, in the design of switching control strategies for active suspensions systems in road vehicles. Performance indices such as decay rate, guaranteed cost, and restriction in the norm of controller gains are considered in these designs. Copyright © 2016 John Wiley & Sons, Ltd.

This paper proposes a methodology of design and control, and shows the main simulation and experimental results for a LLCC Series-parallel resonant converter applied to Wireless Power Transmission (WPT) in-motion. Using Induced Power Transfer (IPT) and considering a near-field energy-transfer method (less than 20 cm), the converter is applied in a small scale electric vehicle (EV). The modeling was derived from inductors with cylindrical spiral shape, considering series association for the emitter. The resonant converter achieves high efficiency (up to 86%) along the full length of the experimental emitter arrangement. Furthermore, an important contribution presented in this paper is the analysis and design of arrangements for the inductive elements of WPT, and the small signal theory applied to a Full-Bridge Phase-Shift (FB-PS) resonant converter. Experimental results are shown for a prototype rated at 1150W, in order to validate the proposed methodology and system, considering wireless energy transfer with 30 mm gap.

O trabalho apresenta uma implementacao da teoria de controladores robustos H∞, juntamente com a restricao de D-Estabilidade e realimentacao da integral do erro de medida usando Inequacoes Matriciais Lineares (LMI), considerando incertezas e objetivando minimizar disturbio no acionamento de motor de inducao trifasico (MIT). A teoria foi implementada no projeto de controle de velocidade do MIT, sendo considerados tres casos distintos no controle de velocidade: i) sem incerteza, ii) incerteza na constante de tempo do rotor e, por fim, iii) incerteza na constante de tempo do rotor e do estator. Foram obtidos otimos resultados com aplicacao de carga nominal, em degrau, na ponta do eix o do MIT.

Este trabalho apresenta um estudo da teoria de controladores robustos usando Inequacoes Matriciais Lineares (LMIs) em acionamento de Motor de Inducao Trifasico (MIT). No controle de velocidade serao considerados tres casos: i) sem falhas por incertezas parametricas, ii) com falha por incerteza na constante de tempo do rotor e iii) com falha por incertezas nas constantes de tempo do rotor e do estator. Apos o projeto dos controladores, inseriu-se na LMI a taxa de decaimento, Gama, calculando-se entao novos controladores para Gama igual a 1 e 10, comparando-se o comportamento da saida apos a aplicacao de um degrau no torque de carga.

Made available in DSpace on 2015-10-21T21:15:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-01-01. Added 1 bitstream(s) on 2015-10-22T09:47:42Z : No. of bitstreams: 1 WOS000353799000001.pdf: 2491613 bytes, checksum: 1e4ae39cf0d5683931b7822f26319e99 (MD5) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) We deal with uncertain systems with networked sliding mode control, subject to time delay. To minimize the degenerative effects of the time delay, a simpler format of state predictor is proposed in the control law. Some ultimate bounded stability analyses and stabilization conditions are provided for the uncertain time delay system with proposed discrete-time sliding mode control strategy. A numerical example is presented to corroborate the analyses. Sao Paulo State Univ UNESP, Dept Elect Engn, Control Res Lab, BR-15385000 Ilha Solteira, SP, Brazil Sao Paulo State Univ UNESP, Dept Elect Engn, Control Res Lab, BR-15385000 Ilha Solteira, SP, Brazil FAPESP: 2011/17610-0

Motivated by the need of testing control strategies, where students can observe the importance of practical test in control theories, and the high price of testing platforms, this study target the classic inverted pendulum control system construction and implementation using wasted components from printers and hard drives, electronic components and an open source microcontroller, resulting in a low cost didactic plant, that not only can be used by graduate students, but even for high-level control theories. In this paper, method of modern control by placement poles with help Ackerman's method is presented.

DOI: 10.14684/intertech.13.2014.218-222 The aim of their paper was to build a low cost inverted pendulum system with parts of dot matrix printers, for the study of control systems. After that, a linear mathematical modeling of this system was deducted. Then, based on experiments at the laboratory, including the frequency response, the transfer functions of the inverted pendulum were obtained. Considering their transfer functions and supposing that the state vector is available, a controller was designed based on the pole placement control design method. The designed controller was implemented in an Programmable Logic Controller (PLC) and was used an software SCADA. This study can be useful in didactic applications, because the proposed procedure presents low cost and their devices (PLC) and software (SCADA) are broadly use in industries. Index Terms - Discrete Control, Feedback Systems, Pole Placement Control, Programmable Logic Control (PLC).

DOI: 10.14684/intertech.13.2014.213-217 This text describes an experience obtained in the implantation of a teaching laboratory, together with a discipline, of focus eminently practical, addressed for the area of automation of processes. It is emphasized as main element the creation of conditions that propitiate to the students motivation for construction of projects of processes control. The main tool used at the laboratory to make possible the projects of processes control is the Programmable Logical Controller (PLC). The processes done at laboratory are controlled through net of PLC's and can be monitored and commanded at the distance by microcomputer. Index Terms - Automation of Processes, Education, Ethernet, PLC, Teaching Laboratory

This paper presents two discrete sliding mode control (SMC) design. The first one is a discrete-time SMC design that doesn't take into account the time-delay. The second one is a discrete-time SMC design, which takes in consideration the time-delay. The proposed techniques aim at the accomplishment simplicity and robustness for an uncertainty class. Simulations results are shown and the effectiveness of the used techniques is analyzed.

Os motores de indução desempenham um importante papel na indústria, fato este que destaca a importância do correto diagnóstico e classificação de falhas ainda em fase inicial de sua evolução, possibilitando aumento na produtividade e, principalmente, eliminando graves danos aos processos e às máquinas. Assim, a proposta desta tese consiste em apresentar um multiclassificador inteligente para o diagnóstico de motor sem defeitos, falhas de curto-circuito nos enrolamentos do estator, falhas de rotor e falhas de rolamentos em motores de indução trifásicos acionados por diferentes modelos de inversores de frequência por meio da análise das amplitudes dos sinais de corrente de estator no domínio do tempo. Para avaliar a precisão de classificação frente aos diversos níveis de severidade das falhas, foram comparados os desempenhos de quatro técnicas distintas de aprendizado de máquina; a saber: (i) Rede Fuzzy Artmap, (ii) Rede Perceptron Multicamadas, (iii) Máquina de Vetores de Suporte e (iv) k-Vizinhos-Próximos. Resultados experimentais obtidos a partir de 13.574 ensaios experimentais são apresentados para validar o estudo considerando uma ampla faixa de frequências de operação, bem como regimes de conjugado de carga em 5 motores diferentes. Induction motors play an important role in the industry, a fact that highlights the importance of correct diagnosis and classification of faults on these machines still in early stages of their evolution, allowing increase in productivity and mainly, eliminating major damage to the processes and machines. Thus, the purpose of this thesis is to present an intelligent multi-classifier for the diagnoses of healthy motor, short-circuit faults in the stator windings, rotor broken bars and bearing faults in induction motors operating with different models of frequency inverters by analyzing the amplitude of the stator current signal in the time domain. To assess the classification accuracy across the various levels of faults severity, the performances of four different learning machine techniques were compared; namely: (i) Fuzzy ARTMAP network, (ii) Multilayer Perceptron Network, (iii) Support Vector Machine and (iv) k-Nearest-Neighbor. Experimental results obtained from 13.574 experimental tests are presented to validate the study considering a wide range of operating frequencies and also load conditions using 5 different motors.