357 research outputs found

    Exponential state estimation for competitive neural network via stochastic sampled-data control with packet losses

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    This paper investigates the exponential state estimation problem for competitive neural networks via stochastic sampled-data control with packet losses. Based on this strategy, a switched system model is used to describe packet dropouts for the error system. In addition, transmittal delays between neurons are also considered. Instead of the continuous measurement, the sampled measurement is used to estimate the neuron states, and a sampled-data estimator with probabilistic sampling in two sampling periods is proposed. Then the estimator is designed in terms of the solution to a set of linear matrix inequalities (LMIs), which can be solved by using available software. When the missing of control packet occurs, some sufficient conditions are obtained to guarantee that the exponentially stable of the error system by means of constructing an appropriate Lyapunov function and using the average dwell-time technique. Finally, a numerical example is given to show the effectiveness of the proposed method

    SATURATED AND ASYMMETRIC SATURATED IMPULSIVE CONTROL SYNCHRONIZATION OF COUPLED DELAYED INERTIAL NEURAL NETWORKS WITH TIME-VARYING DELAYS

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    This paper considers control systems with impulses that are saturated and asymmetrically saturated which are used to examine the synchronization of inertial neural networks (INNs) with time-varying delay and coupling delays. Under the theoretical discussions, mixed delays, such as transmission delay and coupling delay are presented for inertial neural networks. The addressed INNs are transformed into first order differential equations utilizing variable transformation on INNs and then certain adequate conditions are derived for the exponential synchronization of the addressed model by substituting saturation nonlinearity with a dead-zone function. In addition, an asymmetric saturated impulsive control approach is given to realize the exponential synchronization of addressed INNs in the leader-following synchronization pattern. Finally, simulation results are used to validate the theoretical research findings

    Advanced Mathematics and Computational Applications in Control Systems Engineering

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    Control system engineering is a multidisciplinary discipline that applies automatic control theory to design systems with desired behaviors in control environments. Automatic control theory has played a vital role in the advancement of engineering and science. It has become an essential and integral part of modern industrial and manufacturing processes. Today, the requirements for control precision have increased, and real systems have become more complex. In control engineering and all other engineering disciplines, the impact of advanced mathematical and computational methods is rapidly increasing. Advanced mathematical methods are needed because real-world control systems need to comply with several conditions related to product quality and safety constraints that have to be taken into account in the problem formulation. Conversely, the increment in mathematical complexity has an impact on the computational aspects related to numerical simulation and practical implementation of the algorithms, where a balance must also be maintained between implementation costs and the performance of the control system. This book is a comprehensive set of articles reflecting recent advances in developing and applying advanced mathematics and computational applications in control system engineering

    Smart Sensor Networks For Sensor-Neural Interface

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    One in every fifty Americans suffers from paralysis, and approximately 23% of paralysis cases are caused by spinal cord injury. To help the spinal cord injured gain functionality of their paralyzed or lost body parts, a sensor-neural-actuator system is commonly used. The system includes: 1) sensor nodes, 2) a central control unit, 3) the neural-computer interface and 4) actuators. This thesis focuses on a sensor-neural interface and presents the research related to circuits for the sensor-neural interface. In Chapter 2, three sensor designs are discussed, including a compressive sampling image sensor, an optical force sensor and a passive scattering force sensor. Chapter 3 discusses the design of the analog front-end circuit for the wireless sensor network system. A low-noise low-power analog front-end circuit in 0.5μm CMOS technology, a 12-bit 1MS/s successive approximation register (SAR) analog-to-digital converter (ADC) in 0.18μm CMOS process and a 6-bit asynchronous level-crossing ADC realized in 0.18μm CMOS process are presented. Chapter 4 shows the design of a low-power impulse-radio ultra-wide-band (IR-UWB) transceiver (TRx) that operates at a data rate of up to 10Mbps, with a power consumption of 4.9pJ/bit transmitted for the transmitter and 1.12nJ/bit received for the receiver. In Chapter 5, a wireless fully event-driven electrogoniometer is presented. The electrogoniometer is implemented using a pair of ultra-wide band (UWB) wireless smart sensor nodes interfacing with low power 3-axis accelerometers. The two smart sensor nodes are configured into a master node and a slave node, respectively. An experimental scenario data analysis shows higher than 90% reduction of the total data throughput using the proposed fully event-driven electrogoniometer to measure joint angle movements when compared with a synchronous Nyquist-rate sampling system. The main contribution of this thesis includes: 1) the sensor designs that emphasize power efficiency and data throughput efficiency; 2) the fully event-driven wireless sensor network system design that minimizes data throughput and optimizes power consumption

    Robotics 2010

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    Without a doubt, robotics has made an incredible progress over the last decades. The vision of developing, designing and creating technical systems that help humans to achieve hard and complex tasks, has intelligently led to an incredible variety of solutions. There are barely technical fields that could exhibit more interdisciplinary interconnections like robotics. This fact is generated by highly complex challenges imposed by robotic systems, especially the requirement on intelligent and autonomous operation. This book tries to give an insight into the evolutionary process that takes place in robotics. It provides articles covering a wide range of this exciting area. The progress of technical challenges and concepts may illuminate the relationship between developments that seem to be completely different at first sight. The robotics remains an exciting scientific and engineering field. The community looks optimistically ahead and also looks forward for the future challenges and new development

    Sincronização de sistemas lur’e com controle amostrado

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    Este trabalho apresenta soluções para o problema de sincronização de sistemas Lur’e mestre-escravo através de uma lei de controle. Inicialmente, o caso de sistemas em tempo discreto é formulado com um controle saturante. Em seguida, no caso de sistemas em tempo contínuo, considera-se um controle a partir de dados amostrados (sampled-data control). A sincronização é abordada como um problema de estabilização do erro entre os estados dos sistemas mestre e escravo, e o controle projetado através de um problema de otimização. No caso de sistemas em tempo discreto, a partir de uma função de Lyapunov quadrática e condições de setor, desigualdades matriciais lineares (LMI) são obtidas com o objetivo de garantir que a diferença entre os estados mestre e escravo convirja assintoticamente para zero na ocorrência da saturação do sinal de controle. Condições de estabilidade seguindo uma modelagem por funções zona-morta também são obtidas, no caso particular onde a não linearidade Lur’e é descrita por uma função linear por partes. Um problema de otimização para o projeto do controlador é proposto com o objetivo de maximizar um conjunto de erros iniciais admissíveis, para os quais a sincronização é garantida. Na abordagem via controle amostrado são considerados uma função de Lyapunov do tipo Lur’e e um funcional looped para a obtenção de condições LMI que garantam a sincronização de sistemas mestre-escravo sempre que o intervalo entre duas amostras respeitar um determinado limite. Um problema de otimização que visa maximizar o intervalo admissível entre duas amostras consecutivas é apresentado. Os resultados das metodologias propostas são avaliados através de exemplos numéricos.This work presents solutions to the synchronization problem of master-slave Lur’e systems via a control law. Initially, the discrete-time systems case is formulated under a saturating control. Then, in the continuous-time systems case, a sampled-data control is considered. Synchronization is addressed as a problem of stabilization of the error between the states of the master and slave systems and the control is designed via an optimization problem. In the discrete-time systems case, from a quadratic Lyapunov function and sector conditions, linear matrix inequalities (LMI) are derived with the objective of ensuring that the difference between the master and slave states converges asymptotically to zero under the saturation of the control signal. Stability conditions based on a dead zone function modeling are also obtained, in the particular case where the Lur’e nonlinearity is described by a piecewise-linear function. An optimization problem for the controller design is proposed in order to maximize a set of admissible initial errors for which the synchronization is guaranteed. In the sampled-data control approach, a Lur’e-type Lyapunov function and a loopedfunctional are considered to derive LMI conditions that guarantee the synchronization of master-slave systems whenever the interval between two samples respects some bounds. An optimization problem that aims to maximize the allowable interval between two consecutive samples is presented. The results of the proposed methodologies are evaluated with numerical examples

    A Modular Approach for Synchronized Wireless Multimodal Multisensor Data Acquisition in Highly Dynamic Social Settings

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    Existing data acquisition literature for human behavior research provides wired solutions, mainly for controlled laboratory setups. In uncontrolled free-standing conversation settings, where participants are free to walk around, these solutions are unsuitable. While wireless solutions are employed in the broadcasting industry, they can be prohibitively expensive. In this work, we propose a modular and cost-effective wireless approach for synchronized multisensor data acquisition of social human behavior. Our core idea involves a cost-accuracy trade-off by using Network Time Protocol (NTP) as a source reference for all sensors. While commonly used as a reference in ubiquitous computing, NTP is widely considered to be insufficiently accurate as a reference for video applications, where Precision Time Protocol (PTP) or Global Positioning System (GPS) based references are preferred. We argue and show, however, that the latency introduced by using NTP as a source reference is adequate for human behavior research, and the subsequent cost and modularity benefits are a desirable trade-off for applications in this domain. We also describe one instantiation of the approach deployed in a real-world experiment to demonstrate the practicality of our setup in-the-wild.Comment: 9 pages, 8 figures, Proceedings of the 28th ACM International Conference on Multimedia (MM '20), October 12--16, 2020, Seattle, WA, USA. First two authors contributed equall

    A switched system approach to exponential stabilization through communication network

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    International audienceThe paper considers a networked control loop, where the plant is a "slave" part, and the remote controller and observer constitute the "master". Since the performance of Networked Control Systems (NCS) depends on the Quality of Service (QoS) available from the network, it is worth to design a controller that takes into account qualitative information on the QoS in realtime. The goal of the design is to provide a controller that guarantees two things: 1) high performances (here expressed by exponential decay rates) when the QoS remains globally the same; 2) global stability when the QoS changes. In order to guarantee the global stability, the controller will switch by respecting a dwell time constraint. The dwell time parameters are obtained by using the switched system theories and the obtained conditions are Linear Matrix Inequalities (LMI). An experiment illustrates how the controller can be implemented for a control over Internet application (remote control of a small robot)

    Proceedings of the NASA Conference on Space Telerobotics, volume 4

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    Papers presented at the NASA Conference on Space Telerobotics are compiled. The theme of the conference was man-machine collaboration in space. The conference provided a forum for researchers and engineers to exchange ideas on the research and development required for the application of telerobotic technology to the space systems planned for the 1990's and beyond. Volume 4 contains papers related to the following subject areas: manipulator control; telemanipulation; flight experiments (systems and simulators); sensor-based planning; robot kinematics, dynamics, and control; robot task planning and assembly; and research activities at the NASA Langley Research Center
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