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为预测冻土路基安装热管后路基温度场的变化情况,对热管耦合冻土路基问题开展数值传热研究是一种比纯实验方法更经济可行的方法。根据是否考虑热管内部热阻及建立的热管耦合冻土路基相变传热模型,热管耦合冻土路基的数值传热算法可基本分为两类。针对这两类基本算法进行了对比分析。结果表明：通过忽略热管内部热阻,利用耦合边界处的等价第三类边界条件及根据实际地温气温条件建立的相变传热模型来研究热管耦合冻土路基问题在工程上更为可行。 相似文献
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传统的位变化方法对非线性耦合方程数据分类问题进行控制时,主要按照专家资料进行分析,导致数据分类出现明显的重叠和波动,具有较高的滞后性,不能确保数据分类方程的灵敏度。提出一种依据关键抽样马尔科夫链模拟的非线性耦合方程数学分类灵敏度分析方法。分析了非线性耦合方程的数学分类过程,按照运算非线性耦合方程分类滞后概率积分表达式,将非线性耦合方程分类滞后概率对基本变量分布参数的偏导数表征的灵敏度,转换成一个特征范数的条件数学期望,该数学期望基本变量在非线性耦合方程分类滞后域中的条件概率密度函数构建而成,采用关键抽样马尔可夫链模拟,将运算非线性耦合方程分类滞后概率的关键抽样样本转换成,基本变量处于非线性耦合方程分类滞后域中的条件样本,通过特征函数在这些条件样本点处的样本均值进行预测,实现非线性耦合方程的数学分类灵敏度分析。实验结果表明,所提方法对非线性耦合方程的数学分类的灵敏度控制效率和精度都优于传统分类方法,具有较高的数学分类灵敏性。 相似文献
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通过使用不同的数值插值算法和函数逼近方法对提出的龙格函数进行分析总结,得出在对应不同类型的算法时,龙格函数是否显出病态性,插值方法是否对于高阶的问题仍然适用的相关结论.对拉格朗日插值、牛顿插值、切比雪夫多项式零点插值、三次样条插值、曲线拟合等数值算法通过具体的Matlab程序,做出他们的相应的函数图形并进行结果分析,以得出每个数值方法的性质,适用范围和优缺点. 相似文献
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依据SIMPLE算法中边界压力的外推格式,结合定压边界条件重新推导了邻近边界内节点的压力计算公式.根据NEUMANN特性给出了新的定压边界速度计算公式,用IDEAL算法来处理压力和速度的耦合.讨论了定压边界流动传热问题的求解步骤.通过几个经典算例将本方法与文献方法进行了对比,结果表明本方法提高了定压边界问题数值解的精度,加快了迭代过程的收敛. 相似文献
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通过马尔可夫分析,构造了求解系统处于平稳状态概率的迭代算法,提出了计算订单的平均缺货水平的近似表达式.数值模拟表明该近似表达式的计算结果与模拟结果非常接近,算法非常有效.数值实验还分析了合作与否以及零件的调拨策略对订单的平均缺货水平的影响. 相似文献
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本文根据直升机旋翼／机体耦合系统的动力稳定性分析模型,采用教学工具软件Maple推导了该系统的全量动力学方程,编写了相应的仿真程序,并对旋翼／机体耦合系统动稳定性试验装置进行了“地面共振”试验仿真,通过仿真结果与试验结果的对比分析,表明本文建立的旋翼／机体耦合系统动稳定性全量动力学方程及其数值计算方法是正确的,仿真结果对直升机“地面共振”试验具有重要指导意义： 相似文献
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侯祥云 《科技成果管理与研究》2021,16(5):6-7
自20世纪50年代起源至今,数值天气预报是被世界各国普遍采用的一种现代天气预报手段.数值天气预报的制作过程比较复杂,需将得到的气象观测数据用物理方程解析,然后以资料信息的形式同化到计算机数值模型上,再通过一系列积分运算,最后得出未来天气的结果,从而对未来一定时段内天气状态进行预知.中国海洋大学特聘教授张绍晴长期从事物理海洋学和地球系统数值模式可预报性研究,是耦合地球系统模式和耦合资料同化研究领域的领军人物. 相似文献
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目前我国工业处于飞速发展阶段,传统的温度控制方法已跟不上工业发展的步伐。为了提高了温度控制的实时性、稳定性和精确度,新的温度控制方法应运而生。本文基于模糊控制技术,介绍耦合温度控制系统的设计思路及对其进行系统分析和算法分析,并通过测量结果反证系统的可行性。 相似文献
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《Journal of The Franklin Institute》2022,359(2):1605-1625
This paper deals with the exponential stabilization of first order ODE-transport PDE coupled at the boundary point. A state feedback boundary control law has been formulated with the help of the backstepping method. The main novelty of this paper is that the stabilization of the coupled system is discussed by Lyapunov theory and the appropriate observer gain is designed by using the linear matrix inequalities (LMIs). An anti-collocated observer design for the corresponding dual system is also presented. The state feedback boundary controller, observer design and the stabilization of the closed-loop system are discussed in detail with illustrative numerical examples. 相似文献
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机械零部件的安全可靠是机械设计的主要目的之一，由于工程材料性的离散性以及制造、安装误差等因素的影响，使机械零部件的参数具有固有的随机性，因此研究这种机械系统的可靠性问题有十分重要的意义，这种研究可以帮助工程设计人员合理地建立机械系统的安全容限和控制随机参数对机械系统安全的影响．将可靠性设计理论与灵敏度分析方法相结合，讨论了螺旋管簧的可靠性的参数灵敏度分析问题，提出了可靠性灵敏度设计的计算方法，研究了正态分布设计参数的改变对螺旋管簧可靠性的影响，给出了可靠性灵敏度的变化规律，根据编制的相关的实用程序，可以迅速准确地得到螺旋管簧的可靠性灵敏度设计信息，为螺旋管簧的可靠性设计提供了理论依据。 相似文献
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This paper investigates the problem of finite-time outer-synchronization for discrete-time complex networks with Markov jump topology in the presence of communication delays and possible information losses and its application to image encryption. A hybrid control, which is subject to both stochastic jumps and deterministic switches, is proposed to realize finite-time and stochastic outer-synchronization for the concerned networks. By utilizing a stochastic Lyapunov functional combined with the average dwell-time method, sufficient conditions are found such that the synchronization error dynamical system is stochastically stable in finite-time. Two numerical examples are presented to illustrate the effectiveness of the proposed method. Finally, the complex network consists of four coupled Lorenz systems are utilized to generate chaotic sequences and a new chaotic image cryptosystem is constructed to transmit encrypted images based on the synchronized drive-response complex networks. Experiments are conducted by using numerical simulation, and the security is analyzed in terms of key space, key sensitivity, histogram distributions, correlation coefficients, information entropy and differential attack measures. The experimental results show that the proposed chaotic image cryptosystem has the advantages of high security against some classical attacks. 相似文献
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This paper offers an efficient sliding manifold design method that minimizes the impact of unmatched disturbances onto SM dynamics and system accuracy. System sensitivity upon unmatched constant or slowly varying external disturbance vector is evaluated by the steady-state dependent criterion function. An infinite set of sliding manifolds that minimize the chosen optimization criterion is determined and a way of selecting a manifold out of that set that provides adopted SM dynamics is suggested. The proposed approach has been demonstrated on numerical examples and verified by simulations. 相似文献
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《Journal of The Franklin Institute》2022,359(2):1112-1143
This article is mainly focused on investigating pinning exponential synchronization of inertial coupled neural networks (ICNNs) under different directed topologies. The traditional method of variable substitution is removed and replaced by non-reduced order method to investigate the dynamical behavior of second-order coupled system. Additionally, by constructing Lyapunov-Krasovskii functional and utilizing matrix decomposition theory as well as M-matrix theory, an adaptive aperiodically intermittent controller is introduced to derive several improved sufficient criteria based on linear matrix inequalities (LMIs). Finally, some examples with numerical simulation are exhibited to confirm the availability of the theoretical results. 相似文献
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This paper is concerned with control design for a generalized Takagi–Sugeno fuzzy system. The Takagi–Sugeno fuzzy system generally describes nonlinear systems by employing local linear system representations, while a generalized fuzzy system to be considered in this paper describes even a wider class of nonlinear systems by representing locally nonlinear systems. For such a generalized system, a stabilizing controller design method is proposed by introducing a new class of non-PDC controllers. A non-PDC controller is a generalized controller of PDC one, which is a traditional fuzzy controller. Stabilizing controller design conditions are given in terms of a set of linear matrix inequalities (LMIs), which are easily numerically solvable. A relaxation method is used to reduce the conservatism of design conditions. Finally, numerical examples are given to illustrate our nonlinear control design and to show the effectiveness over other existing results. 相似文献
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《Journal of The Franklin Institute》2018,355(18):9374-9395
This paper presents a new control method for autonomous vehicles. The design goal is to perform the automatic lane keeping under multiple system constraints, namely actuator saturation of the steering system, roads with unknown curvature and uncertain lateral wind force. Such system constraints are explicitly taken into account in the control design procedure. To achieve this goal, we propose a new constrained Takagi–Sugeno fuzzy model-based control method using fuzzy Lyapunov control framework. The resulting non-parallel distributed compensation controller is able to handle not only various system constraints but also a large variation range of vehicle speed. In particular, Taylor’s approximation method is exploited to reduce not only the numerical complexity for real-time implementation but also the conservatism of the results. The design conditions are strictly expressed in terms of linear matrix inequalities which can be efficiently solved with available numerical solvers. The effectiveness of the proposed control method is demonstrated through both simulation and hardware experiments with various driving scenarios. 相似文献
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Model order reduction based on general orthogonal polynomials in the time domain for coupled systems
In this paper, we present a new model order reduction (MOR) method based on general orthogonal polynomials for coupled systems in the time domain. By constructing proper projection matrices, the reduced system not only can preserve the structure of the original system but also can match the first several coefficients of the original output. We study the error bound and the stability of the reduced system as well. Finally, two numerical examples are shown to illustrate the effectiveness of the method. 相似文献
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对于具有不确定参数的Lorenz混沌系统，通过参数调节和自适应技术讨论了两个同结构Lorenz混沌系统的同步问题。自适应控制器和参数调节律均由Lyapunov稳定行理论来确定。数字仿真表明了该方法的有效性和实用性。 相似文献