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Optimization of three-loop missile autopilot gain under crossover frequency constraint

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Defence Technology（防务技术） 2016年第1期12卷 32-38页

作者： M.A.ABD-ELATIF Long-jun QIAN yu-ming bo School of Automation University of Science and TechnologyNanjing

The open-loop crossover frequency is pointed as an important parameter for practical autopilot design. Since different gain designs may achieve the same open-loop crossover frequency, it should be neither considered as a performance objective of the optimal autopilot design-schemes nor neglected. Besides, the main assignment of the autopilot is to drive the missile to track the acceleration commands, so the autopilot gain design should be evaluated directly according to the resultant tracking performance. For this purpose, an optimal design methodology of the three-loop missile autopilot is introduced based on constraint optimization technique, where the tracking performance is established analytically as the design objective and the open-loop crossover frequency is formed as inequality constraint function, both are manipulated in terms of stable characteristic parameters of the autopilot closed-loop. The proposed technique is implemented with the assistance of a numerical optimization algorithm which automatically adjusts the design parameters. Finally, numerical simulation results are provided to demonstrate the effectiveness and feasibility of the proposed approach compared with that in some references.

关键词：导弹自动驾驶仪频率约束优化技术三回路增益设计方法跟踪性能数值模拟

Mechanism model for shale gas transport considering diffusion, adsorption/desorption and Darcy flow

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Journal of Central South University 2013年第7期20卷 1928-1937页

作者： WEI ming-qiang DUAN Yong-gang FANG Quan-tang WANG Rong yu bo-ming yu Chun-sheng State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University) Chengdu 610500 China School of Physics Huazhong University of Science and Technology Wuhan 430074 China

To improve the understanding of the transport mechanism in shale gas reservoirs and build a theoretical basic for further researches on productivity evaluation and efficient exploitation, various gas transport mechanisms within a shale gas reservoir exploited by a horizontal well were thoroughly investigated, which took diffusion, adsorption/desorption and Darcy flow into account. The characteristics of diffusion in nano-scale pores in matrix and desorption on the matrix surface were both considered in the improved differential equations for seepage flow. By integrating the Langmuir isotherm desorption items into the new total dimensionless compression coefficient in matrix, the transport function and seepage flow could be formalized, simplified and consistent with the conventional form of diffusion equation. Furthermore, by utilizing the Laplace change and Sethfest inversion changes, the calculated results were obtained and further discussions indicated that transfer mechanisms were influenced by diffusion, adsorption/desorption. The research shows that when the matrix permeability is closed to magnitude of 10^-9D, the matrix flow only occurs near the surfacial matrix; as to the actual production, the central matrix blocks are barely involved in the production; the closer to the surface of matrix, the lower the pressure is and the more obvious the diffusion effect is; the behavior of adsorption/desorption can increase the matrix flow rate significantly and slow down the pressure of horizontal well obviously.

关键词： shale gas diffusion adsorption/desorption transport mechanism horizontal well

Influence of Inhomogeneity on Critical Behavior of Earthquake Model on Random Graph

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Communications in Theoretical Physics 2006年第2X期46卷 261-264页

作者： ZHANG Duan-ming SUN Fan yu bo-ming PAN Gui-Jun YIN Yah-Ping LI Rui SU Xiang-Ying Department of Physics Huazhong University of Science and Technology Wuhan 430074 China

We consider the earthquake model on a random graph. A detailed analysis of the probability distribution of the size of the avalanches will be given. The model with different inhomogeneities is studied in order to compare the critical behavior of different systems. The results indicate that with the increase of the inhomogeneities, the avalanche exponents reduce, i.e., the different numbers of defects cause different critical behaviors of the system. This is virtually ascribed to the dynamical perturbation.

关键词： self-organized criticality earthquake model critical behavior power-law finite size scaling random network

Critical Behaviors in a Stochastic One-Dimensional Sand-Pile Model

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Communications in Theoretical Physics 2005年第2X期44卷 316-320页

作者： ZHANG Duan-ming SUN Hong-Zhang LI Zhi-Hua PAN Gui-Jun yu bo-ming YIN Yan-Ping SUN Fan Department of Physics Huazhong University of Science and Technology Wuhan 430074 China Department of Mathematics & Physics Henan University of Science and TechologyLuoyang 471003 China Department of Physics Hubei University Wuhan 430062 China

A one-dimensional sand-pile model (Manna model), which has a stochastic redistribution process, is studied both in discrete and continuous manners. The system evolves into a critical state after a transient period. A detailed analysis of the probability distribution of the avalanche size and duration is numerically investigated. Interestingly,contrary to the deterministic one-dimensional sand-pile model, where multifractal analysis works well, the analysis based on simple finite-size scaling is suited to fitting the data on the distribution of the avalanche size and duration. The exponents characterizing these probability distributions are measured. Scaling relations of these scaling exponents and their universality class are discussed.

关键词： self-organized criticality power-law sand-pile model finite-size scaling universality class

Self-organized Criticality in an Earthquake Model on Random Network

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Communications in Theoretical Physics 2006年第2期45卷 293-296页

作者： ZHANG Duan-ming SUN Fan yu bo-ming PAN Gui-Jun SUN Hong-Zhang YIN Yah-Ping LI Rui SU Xiang-Ying Department of Physics Huazhong University of Science and Technology Wuhan 430074 China

A simplified Olami-Feder-Christensen model on a random network has been studied. We propose a new toppling rule -- when there is an unstable site toppling, the energy of the site is redistributed to its nearest neighbors randomly not averagely. The simulation results indicate that the model displays self-organized criticality when the system is conservative, and the avalanche size probability distribution of the system obeys finite size scaling. When the system is nonconservative, the model does not display scaling behavior. Simulation results of our model with different nearest neighbors q is also compared, which indicates that the spatial topology does not alter the critical behavior of the system.

关键词： self-organized criticality earthquake model finite size scaling random network

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数字岩心孔隙结构的分形表征及渗透率预测

重庆大学学报（自然科学版） 2011年第4期34卷 88-94页

作者：赵明郁伯铭长江大学物理科学与技术学院湖北荆州434023 华中科技大学物理学院湖北武汉430074

基于多孔介质孔隙结构的分形理论,对9种数字岩心样品的孔隙相和固体相结构进行了分形表征。计算结果表明固体相的分形维数通常要大于孔隙相的分形维数,其分形标度区间的宽度要小于孔隙相的标度区间宽度。这表明数字岩心是一种近似两相... 详细信息

基于多孔介质孔隙结构的分形理论,对9种数字岩心样品的孔隙相和固体相结构进行了分形表征。计算结果表明固体相的分形维数通常要大于孔隙相的分形维数,其分形标度区间的宽度要小于孔隙相的标度区间宽度。这表明数字岩心是一种近似两相分形多孔介质。在此基础上,对9种数字岩心样品的孔隙度、体积分数和渗透率进行了预测。预测结果表明数字岩心孔隙结构的分形理论在描述介质的孔隙度和渗透率方面是有效的。而且在近似两相分形介质中,对固相的分形描述似乎更加有效。当用分形理论对数字岩心样品的渗透率进行预测时,其准确地确定最大孔隙尺寸至关重要。最后,通过对比发现,在预测渗透率方面,采用的FT方法要比目前国际上通用的PNEM方法更加准确,也更加具有普适性和计算成本更低。

关键词：数字岩心分形表征孔隙结构渗透率最大孔隙尺寸

Fractal Analysis of Surface Roughness of Particles in Porous Media

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Chinese Physics Letters 2010年第2期27卷 157-160页

作者：蔡建超郁伯铭邹明清梅茂飞 School of Physics Huazhong University of Science and TechnologyWuhan 430074

A fractal dimension for roughness height （RH） is introduced to characterize the degree of roughness or disorder of particle surface characters which significantly influence physical-chimerical processes in porous media. An analytical expression for the fractal dimension of RH on statistically self-similar fractal surfaces is derived and is expressed as a function of roughness parameters. The specific surface area （SSA） of porous materials with spherical particles is also derived, and the proposed fractal model for the SSA of particles with rough surfaces is expressed as a function of fractal dimension for RH and fractal dimension for particle size distribution, relative roughness of particle surface, and ratio of the minimum to the maximum particle diameters of spherical particles.

关键词： Chinese climate network complex systems small world community

Investigation of Dynamic Behavior in 1D Non-uniform Granular System

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Communications in Theoretical Physics 2005年第3X期44卷 551-554页

作者： ZHANG Duan-ming SU Xiang-Ying yu bo-ming LI Rui PAN Gui-Jun SUN Hong-Zhang YIN Yan-Ping SUN Fan HE Min-Hua LIU Dan Department of Physics Huazhong University of Science and Technology Wuhan 430074 China

We present a non-uniform granular system in one-dimensional case, whose granularity distribution has the fractal characteristic. The particles are subject to inelastic mutual collisions and obey Langevin equation between collisions. By Monte Carlo simulation we study the dynamic actions of the system. Far from the equilibrium, i.e., τ 〉〉 τe, the results of simulation indicate that the inhomogeneity of the system and the inelasticity of the particles have great influences on the dynamic properties of the system, and correspondingly the influence of the inhomogeneity is more significant.

关键词： inelasticity restitution coefficient e inhomogeneity fractal dimension D non-uniform granular system

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基于冗余字典的多特征压缩感知目标跟踪算法

兵工学报 2017年第6期38卷 1140-1146页

作者：朱甦薄煜明何亮南京理工大学自动化学院江苏南京210094 南京理工大学紫金学院电子信息与光电技术学院江苏南京210046

针对多特征压缩感知算法中,要求信号稀疏表示的基是一个正交矩阵的问题,提出了提取红外与可见光的多特征目标构造冗余字典子空间下的稀疏表示,分析了压缩感知算法中感知矩阵的选择和稀疏信号的重构。根据对信号稀疏表示的重构,提出粒子... 详细信息

针对多特征压缩感知算法中,要求信号稀疏表示的基是一个正交矩阵的问题,提出了提取红外与可见光的多特征目标构造冗余字典子空间下的稀疏表示,分析了压缩感知算法中感知矩阵的选择和稀疏信号的重构。根据对信号稀疏表示的重构,提出粒子滤波框架下基于冗余字典的多特征压缩感知跟踪方法,能够自动检测复杂场景中出现的动态目标。实验结果表明,与其他经典算法相比,该算法在光照变化、相似外形的干扰目标遮挡等复杂场景中具有更好的鲁棒性及实时性。

关键词：信息处理技术冗余字典压缩感知粒子滤波目标跟踪