The control problem of spacecraft eigenaxis maneuver in the presence of parametric uncertainty and external disturbance is addressed in this paper. Modified Rodrigues parameters (MRPs) are utilized as the attitude p...
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ISBN:
(纸本)9781467355339
The control problem of spacecraft eigenaxis maneuver in the presence of parametric uncertainty and external disturbance is addressed in this paper. Modified Rodrigues parameters (MRPs) are utilized as the attitude parameters for the non-redundancy. An eigenaxis maneuver control law with feedback and feed-forward terms is presented for the nominal system. The transient response of close loop system can be adjusted according to an approximate second order system. To improve the robustness, integral sliding mode (ISM) technique is adopted to reject undesirable effects and track nominal trajectory. The resulting controller can perform the eigenaxis maneuver in the presence of parametric uncertainty and external disturbance while possess good system performance. The effectiveness of the proposed method is demonstrated by simulation results.
This paper presents a novel maximum power point (MPP) tracking (MPPT) method to increase photovoltaic (PV) system performance during partially shaded conditions (PSCs). The method is based on voltage scanning method. ...
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This paper presents a novel maximum power point (MPP) tracking (MPPT) method to increase photovoltaic (PV) system performance during partially shaded conditions (PSCs). The method is based on voltage scanning method. Voltage band method and restricted voltage scanning method is used to increase the scanning speed. A method is proposed to determine whether partial shading occurs. The main advantage of the proposed method is the ability to search the global peak fast. Simulation results shows the good performance of proposed method.
This paper presents a new method based on the polytopic linear differential inclusion and the robust mixed H2/∞ filtering for the design of the nonlinear filter with non-Gaussian noises. The main goal is to solve the...
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ISBN:
(纸本)9781467355322
This paper presents a new method based on the polytopic linear differential inclusion and the robust mixed H2/∞ filtering for the design of the nonlinear filter with non-Gaussian noises. The main goal is to solve the problems of the complexity and large calculation number in the general nonlinear filter and the filtering design problem for systems with the non-Gaussian noises. The noises considered in the paper involve two different kinds of noises: white noises and energy bounded noises. Differing from the linearization in most nonlinear filters, the estimation error system for the nonlinear system is represented by an uncertain polytopic linear model, based on which, the rectification equations for the predicted errors are designed following the robust mixed H2/∞ filtering. The state estimates for the nonlinear system are given through updating the predictions by the rectified quantities, where, the state predicted quantities of the nonlinear system are gained by the prediction equation of the EKF. The evident advantage of the new filter is the filter coefficients of the rectification equation are constant, without the need to evaluate the Jacobian matrixes. As a result, the calculation number for the new filter is decreased much and the real-time performance of the new filter is much better than the EKF, though the accuracy is a little decline. Its effectiveness is demonstrated by using an example and the statistics result of the calculation number for the filters in the example.
An optimal time-varying sliding mode controller based on SDRE approach is proposed in this paper for re-entry vehicle attitude control in the presence of parametric uncertainties and external disturbances. Firstly, an...
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ISBN:
(纸本)9781467355339
An optimal time-varying sliding mode controller based on SDRE approach is proposed in this paper for re-entry vehicle attitude control in the presence of parametric uncertainties and external disturbances. Firstly, an optimal time-varying sliding surface is obtained through the minimization of a given performance index function and the philosophy of time-varying sliding mode control. Subsequently, a discontinuous control law is designed for guaranteeing the existence of the sliding mode throughout the entire response of the system. Therefore, the global robustness can be ensured. Simulation example is finally given to illustrate the effectiveness of the proposed controller.
A chaotic particle swarm optimization (CPSO) algorithm is proposed by introducing chaos state into the original Particle Swarm Optimization (PSO) which aims to solving the flaws of easy plunging into local optimum and...
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ISBN:
(纸本)9781467355339
A chaotic particle swarm optimization (CPSO) algorithm is proposed by introducing chaos state into the original Particle Swarm Optimization (PSO) which aims to solving the flaws of easy plunging into local optimum and losing search ability in the last period for the fast particle velocity decrease. CPSO algorithm takes advantage of the ergodicity, randomicity, and regularity of chaos to make chaotic searching for the global extremun at the same time with the particle swarm optimization. This algorithm synthesizes the high efficiency of global optimization of PSO algorithm and the ergodicity and randomicity of local search of chaotic algorithm. This paper utilizes aforementioned algorithm to identify the Bouc-Wen hysteresis model for piezoelectric ceramic actuators (PCA). The experimental results show that the model identified by CPSO algorithm has better performance than that by PSO algorithm.
The research of networked fire control system simulation plays an important role in modern warfare. Federates of simulation systems based on High Level Architecture (HLA) have a poor reusability. In order to improve t...
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The research of networked fire control system simulation plays an important role in modern warfare. Federates of simulation systems based on High Level Architecture (HLA) have a poor reusability. In order to improve their reusability, the idea of componentization was used to divide federates into several smaller reusable modules by analyzing the internal information flow of the federates. By component technology, three types of small components which have better reusability were designed, including common components, special components and communication components. These components can be used to build a multiple complex models which can be combined with new simulation frameworks to form defense simulation systems for different attacking targets. A simulation task was designed to verify the flexibility and reusability of the designed components and to improve the function of the federates, which effectively improved development efficiency of simulation systems.
This paper presents observer-based fuzzy control for nonlinear fractional-order systems with the fractional order α satisfying 1 < α < 2 via fuzzy T-S models. Using the properties of the Kronecker product and ...
This paper presents observer-based fuzzy control for nonlinear fractional-order systems with the fractional order α satisfying 1 < α < 2 via fuzzy T-S models. Using the properties of the Kronecker product and LMI approach, the feedback and observer gain matrices are designed. By this method, the state of nonlinear system described as the fuzzy T-S model is convergent to the equilibrium and the observer error is convergent to zero. Finally, the simulation result of a numerical example is given to illustrate the effectiveness of this method.
An adaptive distributed differential evolution algorithm is proposed based on the change of the individual's fitness value. Firstly, the initial population is divided into several subpopulations. When the migratio...
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An adaptive distributed differential evolution algorithm is proposed based on the change of the individual's fitness value. Firstly, the initial population is divided into several subpopulations. When the migration condition is satisfied, the best individual in each subpopulation will replace the worst individual of its neighbor subpopulations according to the Von Neumann topology. The migration mechanism among subpopulations enables the information to be communicated in the whole population. Meanwhile, the adaptive mechanism of F and CR is presented for assigning different F and CR to each individual according to the individual's fitness. Numerical results show that, the proposed algorithm is beneficial to explore the solution space, which can avoid the premature convergence and search the excellent solutions.
Real-time bidding(RTB)advertising is a fast-growing business model in online display advertising *** the guaranteed display advertising,it utilizes programmatic instantaneous auction to price and sell ad inventory o...
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Real-time bidding(RTB)advertising is a fast-growing business model in online display advertising *** the guaranteed display advertising,it utilizes programmatic instantaneous auction to price and sell ad inventory on a per-impression *** enbales advertisers to target audiences at demographic,psychographic or behavioral levels across a wide range of *** RTB markets,information about target audiences is usually disclosed to advertisers,while information about publishers(*** ranking,advertising page)are typically not avaliable for advertisers,especially in real-time *** leads to a serious information asymmetry problem in RTB markets,which has significant influence on both advertisers’bidding strategies and publishers’*** this paper,we study the information disclosure strategies of publishers in case when the disclosure may incur an extra *** address this information asymmetry problem by first formulating the RTB auction as an second-price sealed-bid game,then discussing equilibrium information disclosure strategies for publishers and also investigating advertisers’bidding strategies in the three information disclosure cases:all disclosed,non-disclosed,and partially *** find that non-disclosed and partially disclosed strategies may lead to an adverse selection effect,and high-quality publishers will be forced to quit the RTB markets.
Real-time bidding(RTB)is an emerging and promising business model for online computational advertising in the age of big *** on analysis of massive amounts of Cookie data generated by Internet users,RTB advertising ha...
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Real-time bidding(RTB)is an emerging and promising business model for online computational advertising in the age of big *** on analysis of massive amounts of Cookie data generated by Internet users,RTB advertising has the potential of identifying in real-time the characteristic and interest of the target audience in each ad impression,automatically delivering best-matched ads,and optimizing their prices via auction-based programmatic buying *** has significantly changed online advertising,evolving from the traditional pattern of"media buying"and"ad-slot buying"to"targetaudience buying",and is expected to be the standard business model for online advertising in the *** this paper,we discussed the current market practice of RTB advertising,presented the key roles and typical business processes in RTB markets,and summarized the current research progresses in the existing *** aim of this paper is to provide useful reference and guidance for future works.
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