956 research outputs found

    A Nonlinear Model for Online Identifying a High-Speed Bidirectional DC Motor

    Get PDF
    The modeling system is a process to define the real physical system mathematically, and the input/output data are responsible for configuring the relation between them as a mathematical model. Most ofthe actual systems have nonlinear performance, and this nonlinear behavior is the inherent feature for thosesystems; Mechatronic systems are not an exception. Transforming the electrical energy to mechanical one orvice versa has not been done entirely. There are usually losses as heat, or due to reverse mechanical, electrical,or magnetic energy, takes irregular shapes, and they are concerned as the significant resource of that nonlinearbehavior. The article introduces a nonlinear online Identification of a high-speed bidirectional DC motor withdead zone and Coulomb friction effect, which represent a primary nonlinear source, as well as viscosity forces.The Wiener block-oriented nonlinear system with neural networks are implemented to identify the nonlin-ear dynamic, mechatronic system. Online identification is adopted using the recursive weighted least squares(RWLS) method, which depends on the current and (to some extent) previous data. The identification fitnessis found for various configurations with different polynomial orders, and the best model fitness is obtainedabout 98% according to normalized root mean square criterion for a third order polynomial

    Identification of the nonlinear systems based on the kernel functions

    Get PDF
    Constructing an appropriate membership function is significant in fuzzy logic control. Based on the multi-model control theory, this article constructs a novel kernel function which can implement the fuzzification and defuzzification processes and reflect the dynamic quality of the nonlinear systems accurately. Then we focus on the identification problems of the nonlinear systems based on the kernel functions. Applying the hierarchical identification principle, we present the hierarchical stochastic gradient algorithm for the nonlinear systems. Meanwhile, the one-dimensional search methods are proposed to solve the problem of determining the optimal step sizes. In order to improve the parameter estimation accuracy, we propose the hierarchical multi-innovation forgetting factor stochastic gradient algorithm by introducing the forgetting factor and using the multi-innovation identification theory. The simulation example is provided to test the proposed algorithms from the aspects of parameter estimation accuracy and prediction performance

    Aplicações De Métodos De Sensoriamento De Vibração Baseados Em Técnicas

    Get PDF
    Orientadores: Fabiano Fruett, Claudio FloridiaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: Sensores à fibra óptica distribuídos têm sido empregados para monitorar vários parâmetros, tais como temperatura, vibração, tensão mecânica, campo magnético e corrente elétrica. Quando comparados a outras técnicas convencionais, tais sensores são vantajosos devido a suas pequenas dimensões, imunidade a interferências eletromagnéticas, alta adaptabilidade, robustez a ambientes nocivos, dentre outros. Sensores acústicos distribuídos em particular são interessantes devido a sua capacidade em serem usados em aplicações tais como monitoração de saúde de estruturas e vigilância de perímetros. Através da análise em frequência da estrutura, por exemplo uma aeronave, uma ponte, um edifício ou mesmo máquinas em uma fábrica, é possível avaliar sua condição e detectar danos e falhas em um estágio primário. Tais soluções podem cobrir ambas as aplicações de detecção de intrusão e monitoração estrutural com mínimas adaptações no sistema sensor. Desta forma, vibrações e distúrbios pequenas estruturas com resolução de dezenas de centímetros e em grandes estruturas ou perímetros com alguns metros de resolução espacial e centenas de quilômetros de alcance podem ser detectadas. Outra característica útil desta solução baseada em fibra óptica é a possibilidade de ser combinada com técnicas de processamento digital de sinais, permitindo a detecção e localização de perturbações rápidas, reconhecimento de padrões de intrusão em tempo real e multiplexação de dados de superfícies estruturais para aplicações SHM. O principal objetivo desta tese é fazer uso desses recursos para empregar técnicas de DAS como soluções de tecnologias- chave para várias aplicações. Neste trabalho, as técnicas de phase-OTDR foram estudadas e as principais contribuições da tese focaram em trazer soluções inovadoras e validações para aplicações de vigilância e vigilância. Este doutorado teve um período sanduíche nas instalações da RISE Acreo AB, Estocolmo, Suécia, onde experimentos foram realizados e foi parte da 42ª Chamada CISB/Saab/CNPqAbstract: Distributed optical fiber sensors have been increasingly employed for monitoring several parameters, such as temperature, vibration, strain, magnetic field and current. When compared to other conventional techniques, these sensors are advantageous due to their small dimensions, lightweight, immunity to electromagnetic interference, high adaptability, robustness to hazardous environments, less complex data multiplexing, the feasibility to be embedded into structures with minimum invasion, the capability to extract data with high resolution from long perimeters using a single optical fiber and detect multiple events along the fiber. In particular, distributed acoustic sensors (DAS) based on optical time domain reflectometry (OTDR), are of high interest, due to their capability to be used in applications such as structural health monitoring (SHM) and perimeter surveillance. Through the frequency analysis of a structure, for instance an aircraft, a bridge, a building or even machines in a workshop, it is possible to evaluate its condition and detect damages and failures at an early stage. Also, OTDR based solutions for vibration monitoring can be easily adapted with minimum setup modifications to detect intrusion in a perimeter, a useful tool for surveillance of military facilities, laboratories, power plants and homeland security. The same OTDR technique can be used as a non-destructive diagnostic tool to evaluate vibrations and disturbances on both small structures with some dozens of centimeters¿ resolution and in big structures or perimeters with some meters of spatial resolution and hundreds of kilometers of reach. Another useful feature of this optical fiber based solution is the possibility to be combined with high-performance digital signal processing techniques, enabling fast disturbance detection and location, real-time intrusion pattern recognition and fast data multiplexing of structure surfaces for SHM applications. The main goal of this thesis is to make use of these features to employ DAS techniques as key enabling technologies solutions for several applications. In this work, OTDR based techniques were studied and the thesis main contributions were focused on bringing innovative solutions and validations for SHM and surveillance applications. This PhD had a sandwich period at Acreo AB, Stockholm, Sweden, where experimental tests were performed and it was part of the 42ª CISB/Saab/CNPq CalDoutoradoEletrônica, Microeletrônica e OptoeletrônicaDoutora em Engenharia Elétrica202816/2015-0CAPESCNP

    Modeling and control of a DC motor coupled to a non-rigid joint

    Get PDF
    Throughout this paper, the model, its parameter estimation and a controller for a solution using a DC motor with a gearbox worm, coupled to a non-rigid joint, will be presented. First, the modeling of a non-linear system based on a DC Motor with Worm Gearbox coupled to a non-rigid joint is presented. The full system was modeled based on the modeling of two sub-systems that compose it—a non-rigid joint configuration and the DC motor with the worm gearbox configuration. Despite the subsystems are interdependent, its modelling can be performed independently trough a carefully chosen set of experiments. Modeling accurately the system is crucial in order to simulate and know the expected performance. The estimation process and the proposed experimental setup are presented. This setup collects data from an absolute encoder, a load cell, voltage and current sensors. The data obtained from these sensors is presented and used to obtaining some physical parameters from both systems. Finally, through an optimization process, the remaining parameters are estimated, thus obtaining a realistic model of the complete system. Finally, the controller setup is presented and the results obtained are also presented.info:eu-repo/semantics/publishedVersio

    Aeronautical Engineering. A continuing bibliography with indexes, supplement 156

    Get PDF
    This bibliography lists 288 reports, articles and other documents introduced into the NASA scientific and technical information system in December 1982

    Dissemination, Future Research and Education:

    Get PDF
    This booklet is one of three final documentations of the results of the COST-Action TU 1403 ‘ADAPTIVE FACADE NETWORK’ to be published next to the proceedings of the Final COST Conference ‘FACADE 2018 – ADAPTIVE!’ and a Special Issue of the Journal of Façade Design & Engineering (JFDE). While the proceedings and the journal present current scientific research papers selected through a traditional peer review process, these three final documentations have another focus and objective. These three documentations will share a more holistic and comparative view to the scientific and educational framework of this COST-Action on adaptive facades with the objective to generate an overview and a summary – different from the more specific approach of the proceedings and connecting to the first publication that was presenting the participating institutions. The three titles are the following and are connected to the deliverables of the responsible Working Groups (WG): Booklet 3.1 Case Studies (WG1) Booklet 3.2 Building Performance Simulation and Characterisation of Adaptive Facades (WG2) Booklet 3.3 Dissemination, Future Research and Education (WG4) Booklet 3.1 concentrates on the definition and classification of adaptive facades by describing the state of the art of real-world and research projects and by providing a database to be published on COST TU 1403 website (http://tu1403.eu/). Booklet 3.2 focusses on comparing simulation and testing methods, tools and facilities. And finally, Booklet 3.3 documents the interdisciplinary, horizontal and vertical networking and communication between the different stakeholders of the COST-Action organised through Short Term Scientific Missions (STSM), Training Schools and support sessions for Early Stage Researchers (ESR) / Early Career Investigators (ECI), industry workshops, and related surveys as specific means of dissemination to connect research and education. All three booklets show the diversity of approaches to the topic of adaptive facades coming from the different participants and stakeholders, such as: architecture and design, engineering and simulation, operation and management, industry and fabrication and from education and research. The tasks and deliverables of Working Group 4 were organized and supported by the following group members and their functions: – Thomas Henriksen, Denmark ESR/ECI – Ulrich Knaack, The Netherlands Chair (2015-16) – Thaleia Konstantinou, The Netherlands ESR/ECI – Christian Louter, The Netherlands Vice-Chair, STSM Coordinator – Andreas Luible, Switzerland Website, Meetings – David Metcalfe, United Kingdom Training Schools – Uta Pottgiesser, Germany Chair (2017-18) As editors and Chairs, we would like to thank the Working Group members and authors from other Working Groups for their significant and comprehensive contributions to this booklet. Moreover, we sincerely thank Ashal Tyurkay for her great assistance during the whole editing and layout process. We also want to thank COST (European Cooperation in Science and Technology)

    Large space structures and systems in the space station era: A bibliography with indexes (supplement 04)

    Get PDF
    Bibliographies and abstracts are listed for 1211 reports, articles, and other documents introduced into the NASA scientific and technical information system between 1 Jul. and 30 Dec. 1991. Its purpose is to provide helpful information to the researcher, manager, and designer in technology development and mission design according to system, interactive analysis and design, structural concepts and control systems, electronics, advanced materials, assembly concepts, propulsion, and solar power satellite systems

    Advances and Trends in Mathematical Modelling, Control and Identification of Vibrating Systems

    Get PDF
    This book introduces novel results on mathematical modelling, parameter identification, and automatic control for a wide range of applications of mechanical, electric, and mechatronic systems, where undesirable oscillations or vibrations are manifested. The six chapters of the book written by experts from international scientific community cover a wide range of interesting research topics related to: algebraic identification of rotordynamic parameters in rotor-bearing system using finite element models; model predictive control for active automotive suspension systems by means of hydraulic actuators; model-free data-driven-based control for a Voltage Source Converter-based Static Synchronous Compensator to improve the dynamic power grid performance under transient scenarios; an exact elasto-dynamics theory for bending vibrations for a class of flexible structures; motion profile tracking control and vibrating disturbance suppression for quadrotor aerial vehicles using artificial neural networks and particle swarm optimization; and multiple adaptive controllers based on B-Spline artificial neural networks for regulation and attenuation of low frequency oscillations for large-scale power systems. The book is addressed for both academic and industrial researchers and practitioners, as well as for postgraduate and undergraduate engineering students and other experts in a wide variety of disciplines seeking to know more about the advances and trends in mathematical modelling, control and identification of engineering systems in which undesirable oscillations or vibrations could be presented during their operation
    corecore