基于自适应迭代学习控制的工作艇收放装置主动减摆策略研究

工作艇收放装置主要用于完成快速、安全地将舰船上的小艇及人员移至水面,或安全回收工作艇至舰船上等海上任务。针对这一典型的欠驱动机械系统,采用拉格朗日方程的方法建立其动力学模型。根据舰船在海上的实际运动情况,对系统的二维动力学模型进行描述,分析小艇摇摆的二维平面摆角,研究其在船体运动影响下的变化情况。然后在上述非线性动力学模型的基础上,针对系统的摆动部分,为其设计自适应迭代控制闭环控制器,达到消摆的目的。最后,仿真结果证明了此控制方法的有效性。     

Focusing of Spherical Nonlinear Pulses for Nonlinear Wave Equations Ⅲ. Subcritical Case

IntroductionConsider the following initial value problem inR1++3={t>0, x∈R3}: ( t2-Δx)ε+ F1( tε p1-1 t+ε), tθε q1-1 tθε) = 0( t2- 4Δx)θε+ F2( tε p2-1 tε, tθε q2-1 tθε) = 0ε t=0=εJ+1U0r,r -ε r0 tε t=0=εJU1r,r -ε r0θε t=0=εJ+1V0r,r -ε 2r0 tθε t=0=εJV1r,r -ε 2r0(1)where r= x with x=(x1,x2,x3)∈R3, r0>0,and 1相似文献   

The variational formulation of a non-equilibrium traffic flow model: Theory and implications

The analysis and numerical solution of non-equilibrium traffic flow models in current literature are almost exclusively carried out in the hyperbolic conservation law framework, which requires a good understanding of the delicate and non-trivial Riemann problems for conservation laws. In this paper, we present a novel formulation of certain non-equilibrium traffic flow models based on their isomorphic relation with optimal control problems. This formulation extends the minimum principle observed by the LWR model. We demonstrate that with the new formulation, generic initial-boundary conditions can be conveniently handled and a simplified numerical solution scheme for non-equilibrium models can be devised. Besides deriving the variational formulation, we provide a comprehensive discussion on its mathematical properties and physical implications.     

Effects of switching costs on customer attitude loyalty to an airport in a multi-airport region

The purpose is to analyze impacts of switching costs on customer attitude loyalty to an airport operator in a Norwegian multi-airport region. A sample of 167 respondents is analyzed by a structural equations modelling approach. Irrespective of customers’ perceptions of switching costs, service quality seems to be the most important customer loyalty driver. For low switching costs customers flight offers are also an important loyalty driver. For high switching costs customers facilities are important. An anticipated reduction in switching costs due to improvements in the regions’ infrastructure thus implies that more attention should be paid to an upgrading of the flight offers in order to create more airport loyalty in future. This may also have some interesting policy implications, which is briefly discussed in the paper.     

单线铁路隧道洞门结构分项系数的研究

根据隧道洞门结构的计算特点,建立了隧道洞门可靠度计算的极限状态设计式,分析了在已知目标可靠指标βnom的情况下,用分位值法计算洞门结构分项系数的基本原理和过程。通过计算实例,对分项系数的影响因素及其概率意义进行了探讨。     

A SOLITARY SOLUTION AND ITS STABILITY IN A 1-D FHN EQUATION

11ntroductionTravellingwavesinanexcitablemediacanbeobservedinchemical,physicalandbiologicalsystems["'J.Anexcitablemediumistheneuralactionpotential,awaveofelectricalactivitythatpropagatesundegradedalonganaxonalmem-brane.Itcanbemodelledbyareaction-diffusionequationoftheformwherex,taremeasuredin"spaceunits"and"timeunits",the"propagator"variableurepre-sentsanelectricpotentialorachemicalconcen-trationoratemperatureincommonapplications,D,isitsdiffusioncoefficient,andthe"recovery"variableof"controlle…     

一种求解线性方程组的方法

本文提出一种求解线性方程组的方法.当系数阵和自由项阵扰动后,求新未知数时,不必重复计算系数阵的逆阵,只要利用首次运算结果,加以适当变换,建立起新的公式,据此就可求出扰动后的未知数.     

迟滞相频特性方法测量方程的一种改进

迟滞相频特性方法经典测量方程由于忽略了测量系统动质量、力传感器刚度及系统支撑刚度的影响,而给阻尼材料动态力学参数测量引入了误差。首先,以试件拉压安装方式为例,推导了考虑上述三方面因素影响的改进测量方程;然后,分别利用经典和改进测量方程对基于某系统获得的测量数据进行了处理,通过对比分析两种方程获得的材料参数,研究了上述因素对阻尼材料动态力学参数测量结果的影响规律。研究成果为迟滞相频特性方法测量系统优化设计及测量数据处理提供了依据。     

基于指数-兰彻斯特方程的岛礁作战效能评估

通过建立指数-兰彻斯特方程模型对海军陆战队兵力夺控珊瑚岛礁兵力编组的作战效能进行评估,分析各战斗阶段的兵力损耗,检验作战方案实施的效果,为优化兵力编组和完善作战方案提供依据.     

车-桥耦合振动的联合方程分析方法

根据d'Alembert原理和有限元理论,分别建立了车辆和桥梁的振动方程;基于车辆密贴理论,轮底接触点位移由桥梁节点位移采用形函数插值得到,接触点作用力等效成桥梁单元的结点力代入桥梁振动方程,将车辆、桥梁振动方程组联立形成了车-桥耦合振动的总体振动方程;采用数值积分的Newmark-β法求解方程组。结果表明:此方法和经典的迭代求解方法是吻合的。