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中国科学:技术科学 2010年第2期 217-217页

作者： LING Quan1, JIN XiaoLing1 & HUANG ZhiLong2.1 Department of Mechanics, Zhejiang University, hangzhou 31002., china 2.2. key laboratory of fluid power transmission and control, Zhejiang University, hangzhou 31002., china

The asymptotic Lyapunov stability of one quasi-integrable Hamiltonian system with time-delayed feedback control is studied by using Lyapunov functions and stochastic averaging method. First, a quasi-integrable Hamiltonian system with time-delayed feedback control subjected to Gaussian white noise excitation is approximated by a quasi-integrable Hamiltonian system without time delay. Then, stochastic averaging method for quasi-integrable Hamiltonian system is used to reduce the dimension of the original system, and after that the Lyapunov function of the averaged It? equation is taken as the optimal linear combination of the corresponding independent first integrals in involution. Finally, the stability of the system is determined by using the largest eigenvalue of the linearized system. Two examples are used to illustrate the proposed procedure and the effects of delayed time on the Lyapunov stability are discussed as well.

关键词： Lyapunov stability Lyapunov function time delay stochastic averaging

Evolution of desertification in a two-dimensional energy balance model coupled with thermodynamics and dynamics

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Science china Earth Sciences 2010年第11期53卷 1726-1733页

作者： CHAO JiPing1,2.& LI YaoKun3,4 1National Marine Environmental Forecasting Center, Beijing 100081, china 2.irst Institute of Oceanography, state Oceanic Administration, Qingdao 2.6061, china 3state key laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 10002., china 4Graduate University of Chinese Academy of Sciences, Beijing 100049, china 1. National Marine Environmental Forecasting Center Beijing 100081 China2. First Institute of Oceanography State Oceanic Administration Qingdao 266061 China3. State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China4. Graduate University of Chinese Academy of Sciences Beijing 100049 China

The relationship between desert evolution and change in albedo has been investigated quasi-analytically using a zonal mean two-dimensional energy balance model which considers the radiation transmission process due to thermodynamics and bound- ary layer movement caused by kinetics. A climate state including temperature, zonal wind, meridional wind and vertical wind can be simulated according to the current zonal distribution of albedo. Given desert distribution, characterized by the value and distribution of albedo, the response of climate on albedo has been studied to analyze the evolution of desert climate. One significant result is that the simple model can reproduce mean meridional circulation. Another result indicates that climate corresponds to two equilibria. This happens when the junction temperature between vegetation and desert is higher than a certain critical value. As for the first equilibrium, the desert belt is predicted to move southward in the northern hemisphere with the increasing values of albedo, which corresponds to the current trend of climate change. For the second equilibrium, vegetation will expand northward with increasing values of albedo, which would indicate a narrowing of the desert belt. In order to determine if the two equilibria exist, new physical models are needed.

关键词： two-dimensional energy balance model desertification two equilibria

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电脉冲消除45钢淬火件的残余应力

浙江大学学报（工学版） 2012年第8期46卷 1407-1411页

作者：郑建毅何闻施彦彬浙江大学流体传动及控制国家重点实验室浙江省先进制造技术重点实验室现代制造工程研究所浙江杭州310027 厦门大学机电工程系福建厦门361005

为了研究电脉冲消除金属材料内部残余应力的效果,通过储能电容器放电产生高能电脉冲,对淬火后的45优质碳素结构钢冷轧薄板件进行放电处理,采用小孔法测定电脉冲处理前后试样内残余应力的变化规律.用于电脉冲处理的脉冲电流为指数衰减的... 详细信息

为了研究电脉冲消除金属材料内部残余应力的效果,通过储能电容器放电产生高能电脉冲,对淬火后的45优质碳素结构钢冷轧薄板件进行放电处理,采用小孔法测定电脉冲处理前后试样内残余应力的变化规律.用于电脉冲处理的脉冲电流为指数衰减的振荡波形,同时满足第一个主峰的电流密度为12.2.A/mm2.单次处理的振荡脉冲持续时间小于0.8ms.试验结果表明,经过电脉冲处理后,45钢淬火件中2.主方向残余应力的幅值均出现较为显著的降低,且两者都出现均化效果.

关键词：电脉冲 45钢残余应力小孔法

基于栅格地图的移动机器人完全遍历算法——矩形分解法

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机械工程学报 2004年第10期40卷 56-61页

作者：田春颖刘瑜冯申坤朱世强浙江大学流体传动及控制国家重点实验室杭州310027

提出移动机器人的一种新的完全遍历算法:矩形分解算法。首先通过机器人环境学习建立栅格地图,对环境中的障碍物实行矩形化建模。而后应用矩形化模型中的关键点将环境分解成为矩形块,最后在这个分块环境的拓扑图中寻找到一条Hamilton路径... 详细信息

提出移动机器人的一种新的完全遍历算法:矩形分解算法。首先通过机器人环境学习建立栅格地图,对环境中的障碍物实行矩形化建模。而后应用矩形化模型中的关键点将环境分解成为矩形块,最后在这个分块环境的拓扑图中寻找到一条Hamilton路径,机器人沿此路径即可实现对环境的完全遍历。为处理复杂的局部情况,又提出基于模板的局部环境处理算法。矩形算法的优点在于机器人可以实现完全自主的复杂环境遍历,并且可以处理未知障碍,从而使算法适合于任意非结构化的工作环境。

关键词：矩形分解算法 Hamilton路径完全遍历栅格地图移动机器人

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双馈风力发电系统的最大风能控制策略

太阳能学报 2008年第7期29卷 797-803页

作者：李辉何蓓重庆大学输配电装备及系统安全与新技术国家重点实验室重庆400044 重庆市电力公司杨家坪供电局重庆400050

在分析变速恒频风力发电系统最大风能捕获策略的基础上,提出了一种通过直接控制双馈发电机转子电流就可实现系统低于额定风速下的最大风能捕获又可使得电机铜耗最小化运行的控制策略。首先,在考虑风力机特性和双馈发电机基本电磁关系的... 详细信息

在分析变速恒频风力发电系统最大风能捕获策略的基础上,提出了一种通过直接控制双馈发电机转子电流就可实现系统低于额定风速下的最大风能捕获又可使得电机铜耗最小化运行的控制策略。首先,在考虑风力机特性和双馈发电机基本电磁关系的基础上,分别推导了双馈发电机定子铜耗最小化运行和最大风能捕获的数学模型。其次,根据双馈发电机最优转子电流的数学模型,建立了双馈风力发电机系统最大风能捕获的控制策略。最后,利用Matlab/Simulink对不同风速下双馈发电机系统的运行性能进行了分析和比较,结果验证了该控制策略的正确性和可行性。

关键词：风力发电双馈发电机最大风能捕获铜耗最小化励磁控制策略

RESEARCH ON THE SIX DEGREES OF FREEDOM VEHICLE MOTION SIMULATOR

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RESEARCH ON THE SIX DEGREES OF FREEDOM VEHICLE MOTION SIMULA...

A MIMO Nonlinear Robust controller for Work-Class ROVs Positioning and Trajectory Tracking control

第四届流体传动国际会议

作者： Wang Xuanyin, Liu Rong, Jia Guangzheng, Cheng Jia The state key {2. of {2. power transmission and control, ZheJiang University Post Code: 31002., hangzhou, china

In this paper, a six degrees of freedom (6 DOF) vehicle motion simulator has been designed. The theoretic and experimental work has been done to the serve system, which uses the four-way valve to control the asymmetric hydraulic cylinder. The result proves that the platform can smoothly move. The synergetic ability of each DOF is good and its performance meets the requirement of the Vehicle motion simulation.

关键词： 6-DOF Stewart Platform Vehicle Motion Simulator

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A MIMO Nonlinear Robust Controller for Work-Class ROVs Posit...

Numerical simulations of the discontinuous progression of cerebral aneurysms based on fluid-structure interactions study

2.11 Chinese control and Decision Conference（CCDC）

作者： Kangwu Zhu and Linyi Gu are with the state key Lab of {2. {2. transmission and control,Zhejiang University,hangzhou,Zhejiang 31002.,china.

In this paper,for the positioning and trajectory tracking control of work-class ROVs with parameter uncertainties and unknown disturbances,a systematically MIMO nonlinear robust controller design method based on adaptive backstepping technique and sliding control is *** Lyapunov stability design method,the locally asymptotically stability of closed-loop control system has been *** effectiveness of controller has been demonstrated by simulation *** simulation results on a work-class ROV proved that the proposed control method has good control performance,and the controller is robust to parameter uncertainties and unknown disturbances.

关键词： Backstepping Sliding control Nonlinear control Work-class ROV Underwater vehicles

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Science china(Physics,Mechanics & Astronomy) 2010年第5期53卷 944-953页

作者： MA XiaoQi1,WANG YueShe1,YU FangJun1 & WANG GuoXiang1,2.1 state key {2. of Multiphase Flow in {2. Engineering,Xi’an Jiaotong University,Xi’an 710049,china 2.Department of Mechanical Engineering,The University of Akron,Akron,OH 4432.-3903,USA 1. state key {2. of Multiphase Flow in {2. Engineering Xi’an Jiaotong University Xi’an 710049 China2. Department of Mechanical Engineering The University of Akron Akron OH 44325-3903 USA

Investigations into the characteristics of hemodynamics will provide a better understanding of the pathology of cerebral aneurysms for *** this work,a steady state discontinuous-growth model of the cerebral aneurysms was *** the assumption of the fluid-structure interaction between the wall of blood vessel and blood,a fluid-structure coupling numerical simulation for this model was built using software ANSYS and *** simulation results showed that as the aneurysm volume increased,a blood flow vortex came forth,the vortex region became asymptotically larger,and eddy density became gradually stronger in *** the emergence of the vortex region,the blood flow in the vicinity of the downstream in the aneurysms volume turned into bifurcated flow,and the location of the flow bifurcated point was shifted with the aneurysm volume growing while directions of the shear stress applied to two sides of the bifurcated point were *** Von Mises stress distribution along the wall of aneurysm volume decreased in the prior period and increased gradually in the later *** maximum stress was in the neck of the volume and the minimum was on the distal end in the whole process of *** was shown that as the aneurysm increased the maximum deformation location of the aneurysm,vertical to the streamline,was transferred from the distal end of the aneurysm to its neck,then back to its distal end of the aneurysm again.

关键词： cerebral aneurysm fluid-structure interaction wall shear stress discontinuous progression

Compensation for time-delayed feedback bang-bang control of quasi-integrable Hamiltonian systems

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中国科学:技术科学 2010年第3期 338-338页

作者： LIU ZhongHua1 & ZHU WeiQiu2.1 Department of Civil Engineering,Xiamen University,Xiamen 361005,china 2.Department of Mechanics,state {2. {2. of fluid power transmission and control,Zhejiang University,hangzhou 31002.,china

The stochastic averaging method for quasi-integrable Hamiltonian systems with time-delayed feedback bang-bang control is first ***,two time delay compensation methods,namely the method of changing control force amplitude (CFA) and the method of changing control delay time (CDT),are *** conditions applicable to each compensation method are ***,an example is worked out in detail to illustrate the application and effectiveness of the proposed methods and the two compensation methods in combination.

关键词： time-delayed feedback control compensation method bang-bang control quasi-integrable Hamiltonian system