837 research outputs found

    Selected topics in robotics for space exploration

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    Papers and abstracts included represent both formal presentations and experimental demonstrations at the Workshop on Selected Topics in Robotics for Space Exploration which took place at NASA Langley Research Center, 17-18 March 1993. The workshop was cosponsored by the Guidance, Navigation, and Control Technical Committee of the NASA Langley Research Center and the Center for Intelligent Robotic Systems for Space Exploration (CIRSSE) at RPI, Troy, NY. Participation was from industry, government, and other universities with close ties to either Langley Research Center or to CIRSSE. The presentations were very broad in scope with attention given to space assembly, space exploration, flexible structure control, and telerobotics

    Chemical Bionics - a novel design approach using ion sensitive field effect transistors

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    In the late 1980s Carver Mead introduced Neuromorphic engineering in which various aspects of the neural systems of the body were modelled using VLSI1 circuits. As a result most bio-inspired systems to date concentrate on modelling the electrical behaviour of neural systems such as the eyes, ears and brain. The reality is however that biological systems rely on chemical as well as electrical principles in order to function. This thesis introduces chemical bionics in which the chemically-dependent physiology of specific cells in the body is implemented for the development of novel bio-inspired therapeutic devices. The glucose dependent pancreatic beta cell is shown to be one such cell, that is designed and fabricated to form the first silicon metabolic cell. By replicating the bursting behaviour of biological beta cells, which respond to changes in blood glucose, a bio-inspired prosthetic for glucose homeostasis of Type I diabetes is demonstrated. To compliment this, research to further develop the Ion Sensitive Field Effect Transistor (ISFET) on unmodified CMOS is also presented for use as a monolithic sensor for chemical bionic systems. Problems arising by using the native passivation of CMOS as a sensing surface are described and methods of compensation are presented. A model for the operation of the device in weak inversion is also proposed for exploitation of its physical primitives to make novel monolithic solutions. Functional implementations in various technologies is also detailed to allow future implementations chemical bionic circuits. Finally the ISFET integrate and fire neuron, which is the first of its kind, is presented to be used as a chemical based building block for many existing neuromorphic circuits. As an example of this a chemical imager is described for spatio-temporal monitoring of chemical species and an acid base discriminator for monitoring changes in concentration around a fixed threshold is also proposed

    A Survey on Reservoir Computing and its Interdisciplinary Applications Beyond Traditional Machine Learning

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    Reservoir computing (RC), first applied to temporal signal processing, is a recurrent neural network in which neurons are randomly connected. Once initialized, the connection strengths remain unchanged. Such a simple structure turns RC into a non-linear dynamical system that maps low-dimensional inputs into a high-dimensional space. The model's rich dynamics, linear separability, and memory capacity then enable a simple linear readout to generate adequate responses for various applications. RC spans areas far beyond machine learning, since it has been shown that the complex dynamics can be realized in various physical hardware implementations and biological devices. This yields greater flexibility and shorter computation time. Moreover, the neuronal responses triggered by the model's dynamics shed light on understanding brain mechanisms that also exploit similar dynamical processes. While the literature on RC is vast and fragmented, here we conduct a unified review of RC's recent developments from machine learning to physics, biology, and neuroscience. We first review the early RC models, and then survey the state-of-the-art models and their applications. We further introduce studies on modeling the brain's mechanisms by RC. Finally, we offer new perspectives on RC development, including reservoir design, coding frameworks unification, physical RC implementations, and interaction between RC, cognitive neuroscience and evolution.Comment: 51 pages, 19 figures, IEEE Acces

    Electrochemical Model-Based Fast Charging: Physical Constraint-Triggered PI Control

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    This paper proposes a new fast charging strategy for lithium-ion (Li-ion) batteries. The approach relies on an experimentally validated high-fidelity model describing battery electrochemical and thermal dynamics that determine the fast charging capability. Such a high-dimensional nonlinear dynamic model can be intractable to compute in real-time if it is fused with the extended Kalman filter or the unscented Kalman filter that is commonly used in the community of battery management. To significantly save computational efforts and achieve rapid convergence, the ensemble transform Kalman filter (ETKF) is selected and tailored to estimate the nonuniform Li-ion battery states. Then, a health- and safety-aware charging protocol is proposed based on successively applied proportional-integral (PI) control actions. The controller regulates charging rates using online battery state information and the imposed constraints, in which each PI control action automatically comes into play when its corresponding constraint is triggered. The proposed physical constraint-triggered PI charging control strategy with the ETKF is evaluated and compared with several prevalent alternatives. It shows that the derived controller can achieve close to the optimal solution in terms of charging time and trajectory, as determined by a nonlinear model predictive controller, but at a drastically reduced computational cost

    Process Monitoring and Control of Microalgae Cultivation

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    Les bioprocédés jouent un rôle important dans la production de substances à haute valeur ajoutée. L’une des cultures les plus intéressantes parmi les biocultures sont les microalgues. Il s’agit d’organismes microscopiques vivant en milieu aquatique et dont la biomasse est une excellente source d’acide gras et de vitamines. De plus, la culture de microalgues pourrait être utilisée à grande échelle pour produire de l’énergie. Dans ce contexte, l’un des modèles les plus simples pour décrire son comportement dynamique est le modèle de Droop. Ce modèle largement utilisé a été choisi pour cette étude. L’estimation d’état est un domaine de l’ingénierie basé sur l’extraction des informations sur les variables inconnues à partir des informations connues. En génie biochimique, il est nécessaire de connaître les variables qui caractérisent l’état interne du procédé dans le but de produire de grandes quantités des substances d’intérêt. Cependant, l’un des problèmes les plus importants dans la conception de l’estimateur est de pouvoir garantir la convergence de l’erreur d’estimation. C’est pourquoi, en se basant sur les propriétés du modèle de Droop, un observateur de Lipschitz est proposé pour estimer les variables d’état à partir de la mesure. Par ailleurs, l'estimation des paramètres à l'aide de l'observateur est discutée en vue d'estimer certains des paramètres du modèle de Droop. Afin d’évaluer les performances de l’observateur dans le contexte de la commande avancée, le contrôle de la concentration de biomasse et de substrat sont introduits. Deux techniques de contrôle sont considérées en couplage avec l’observateur : le contrôle « backstepping » et le contrôle par linéarisation entrée/sortie. Le suivi de la consigne et le rejet de perturbation sont également étudiés pour ces stratégies. Pour terminer, une extension du modèle de Droop est étudiée pour la production de substances lipidiques. Une structure d’estimation de l’ensemble des variables d’état est ainsi démontrée. ---------- Bioprocesses play an important role to produce high-value products. One of the most interesting cultures among the biocultures is microalgae. It is a microscopic organism existing in aquatic environment. The biomass from this culture is a great source of fatty acids and vitamins. Large scale microalgae culture can be used to produce energy. One of the simplest models to describe the dynamic behaviour of the culture is the Droop model. This widely used model has been chosen for this study. State estimation is a field of control engineering that extracts information about unknown variables based on known information. In bioprocess engineering, in order to produce high amounts of valued product, it is necessary to know about internal state variables of the process. One of the most important problems in designing the estimator is to guarantee the stability of the error dynamics. Based on the properties of the Droop model, a Lipschitz observer is proposed to estimate the state variables from measurement. Moreover, the parameter estimation using the Lipschitz observer is discussed in order to estimate some of the parameters of the Droop model. In order to see the observer performance with advanced controller, the biomass and the substrate concentration control are introduced. Two observer- based controllers, input-output linearization and backstepping technique, are considered. The setpoint tracking and the load rejection problem are studied for both strategies. Finally, a lipid production model as an extension of the Droop model is introduced. The observability property of the model is explained. At the end, a structure for the estimation of all state variables using measurement is demonstrated

    Resilient and Real-time Control for the Optimum Management of Hybrid Energy Storage Systems with Distributed Dynamic Demands

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    A continuous increase in demands from the utility grid and traction applications have steered public attention toward the integration of energy storage (ES) and hybrid ES (HESS) solutions. Modern technologies are no longer limited to batteries, but can include supercapacitors (SC) and flywheel electromechanical ES well. However, insufficient control and algorithms to monitor these devices can result in a wide range of operational issues. A modern day control platform must have a deep understanding of the source. In this dissertation, specialized modular Energy Storage Management Controllers (ESMC) were developed to interface with a variety of ES devices. The EMSC provides the capability to individually monitor and control a wide range of different ES, enabling the extraction of an ES module within a series array to charge or conduct maintenance, while remaining storage can still function to serve a demand. Enhancements and testing of the ESMC are explored in not only interfacing of multiple ES and HESS, but also as a platform to improve management algorithms. There is an imperative need to provide a bridge between the depth of the electrochemical physics of the battery and the power engineering sector, a feat which was accomplished over the course of this work. First, the ESMC was tested on a lead acid battery array to verify its capabilities. Next, physics-based models of lead acid and lithium ion batteries lead to the improvement of both online battery management and established multiple metrics to assess their lifetime, or state of health. Three unique HESS were then tested and evaluated for different applications and purposes. First, a hybrid battery and SC HESS was designed and tested for shipboard power systems. Next, a lithium ion battery and SC HESS was utilized for an electric vehicle application, with the goal to reduce cycling on the battery. Finally, a lead acid battery and flywheel ES HESS was analyzed for how the inclusion of a battery can provide a dramatic improvement in the power quality versus flywheel ES alone

    Advances in Solid State Circuit Technologies

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    This book brings together contributions from experts in the fields to describe the current status of important topics in solid-state circuit technologies. It consists of 20 chapters which are grouped under the following categories: general information, circuits and devices, materials, and characterization techniques. These chapters have been written by renowned experts in the respective fields making this book valuable to the integrated circuits and materials science communities. It is intended for a diverse readership including electrical engineers and material scientists in the industry and academic institutions. Readers will be able to familiarize themselves with the latest technologies in the various fields

    Attosecond Streaking in the Water Window: A New Regime of Attosecond Pulse Characterization

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    We report on the first streaking measurement of water-window attosecond pulses generated via high harmonic generation, driven by sub-2-cycle, CEP-stable, 1850 nm laser pulses. Both the central photon energy and the energy bandwidth far exceed what has been demonstrated thus far, warranting the investigation of the attosecond streaking technique for the soft X-ray regime and the limits of the FROGCRAB retrieval algorithm under such conditions. We also discuss the problem of attochirp compensation and issues regarding much lower photo-ionization cross sections compared with the XUV in addition to the fact that several shells of target gases are accessed simultaneously. Based on our investigation, we caution that the vastly different conditions in the soft X-ray regime warrant a diligent examination of the fidelity of the measurement and the retrieval procedure.Comment: 14 Pages, 12 figure
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