Aimed at the rotor speed unmeasured, this paper presents a speed sensorless control strategy with observer for permanent magnet wind turbine generator based on port-controlled Hamiltonian (PCH) model. The PCH model is...
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Aimed at the rotor speed unmeasured, this paper presents a speed sensorless control strategy with observer for permanent magnet wind turbine generator based on port-controlled Hamiltonian (PCH) model. The PCH model is established by taking full advantage of the physics structure of wind turbine system and then the full-order observer is proposed based the PCH model to estimate rotor speed. This structure of controller is simple but also reflecting physical meaning. Moreover, an adaptive controller is investigated under the uncertain parameters and the external disturbance. The proposed strategy is proved valid by the simulation illustration.
In this paper, genetic algorithm and modified dynamic programming are applied to path planning of robotic fish for the first time. Using grid method to the environment modeling and applying genetic algorithm to the pa...
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To bridge the gap between insufficiency of existing proximity authentication solutions and the increasing demand of high security guarantee for access control systems, we develope a WISP-based access control system co...
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Generally, localization is a nonlinear problem, while linearization is used to simplify this problem. Reasonable approximations could be achieved when signal-to-noise ratio (SNR) is large enough. Energy is a critical ...
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Generally, localization is a nonlinear problem, while linearization is used to simplify this problem. Reasonable approximations could be achieved when signal-to-noise ratio (SNR) is large enough. Energy is a critical resource in wireless sensor networks, and system lifetime needs to be prolonged through the use of energy efficient strategies during system operation. In this paper, a closed-form solution for received signal strength (RSS)-based source localization in wireless sensor network (WSN) is obtained. A sensor selection method is proposed to improve the localization accuracy as well as to save energy consumption. By selecting only a limited number of sensor nodes based on the model accuracy and geometry structure analysis, localization performance is improved, and energy consumption is reduced. In addition, extensive simulations are presented to demonstrate that the estimation performance with the proposed sensor selection method is better than that without sensor selection.
A robust predictive control algorithm based on memory state feedback is proposed for a class of uncertain discrete time system with input constraint and multiple state delays. By introducing Lyapunov-Krasovskii functi...
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A robust predictive control algorithm based on memory state feedback is proposed for a class of uncertain discrete time system with input constraint and multiple state delays. By introducing Lyapunov-Krasovskii function and using linear matrix inequality (LMI) method, the algorithm can convert the infinite time domain optimization problems into linear programming problems. Sufficient conditions of the existence and explicit expression for the memory state feedback controller are obtained, and the control input can satisfy constraint as well. Asymptotical stability of the closed-loop system and minimum of robust performance index can be guaranteed simultaneously. Finally, the simulation results illustrate the effectiveness of the proposed algorithm.
To deal with the problems caused by unmatched uncertainties and external load disturbance exist in mill hydraulic servo position system, a robust adaptive controller design method is presented in this paper. The contr...
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To deal with the problems caused by unmatched uncertainties and external load disturbance exist in mill hydraulic servo position system, a robust adaptive controller design method is presented in this paper. The controller is composed of a state feedback controller and an adaptive compensator, the state feedback controller is obtained by solving a Riccati equation, and the compensator is obtained by estimating the upper bounds of the unknown external disturbances. It is proved that the global asymptotic stability of the resulting closed-loop system can be guaranteed. Finally, simulation results for the mill hydraulic servo position system illustrate the validity of the proposed algorithm.
This paper proposes a constructive way to design dynamic output feedback control law to stabilize a class of nonlinear systems with unknown control coefficients. The unknown parameters are described in polytopic forms...
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It has been proved that Asymmetric cryptography can be used in Wireless Sensor Networks (WSNs). In this paper, we propose a secure Identity-based routing protocol, which can ensure that the nodes in routing discovery ...
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The most frequently used component of a wind turbine is bearing which failure could lead to malfunction and ultimately complete stall in a mission-critical equipment. Hence, bearing fault detection is an imperative pa...
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The most frequently used component of a wind turbine is bearing which failure could lead to malfunction and ultimately complete stall in a mission-critical equipment. Hence, bearing fault detection is an imperative part of preventive maintenance procedures in a wind turbine. This paper presents a free parameter approach to implement bearing condition monitoring and fault diagnosis. This approach extracts the amplitude and frequency modulations of faulty vibration signals that measured from a wind turbine system. The amplitude demodulation is inherent, and the fault frequency will be detected from the spectrums of the signal. The effectiveness of this approach has been validated by using simulated signal and experimental evaluation.
Terahertz time-domain spectroscopy have been applied in research of four different varieties of Chinese green tea, the absorption and refractive Terahertz Spectrum of these tea were got in the range of 0.2 to 1.5 THz....
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