多排式轴向柱塞液压马达缸体的关键技术研究

在总结国内外单排式轴向柱塞液压马达研究成果的基础上,结合多排与单排式轴向柱塞马达之间的异同,对多排式轴向柱塞马达的缸体结构模型进行分析,并以双排式轴向柱塞马达为例,研究了双排式轴向柱塞马达缸体设计的关键技术,采用参数化公式推导出双排式轴向柱塞马达缸体结构的理论设计公式,建立了双排式轴向柱塞马达缸体的数学模型。为多排式轴向柱塞马达关键技术的进一步研究提供了重要的理论依据。     

高性能永磁交流伺服系统研究

重点介绍了永磁交流伺服系统的控制策略,位置检测和辨识、主电路和驱动技术等关键技术.在研究了其物理方程、转矩方程和等效电路的基础上,提出了永磁同步电机的数学模型.叙述了矢量控制的原理,构建了永磁同步电机交流伺服系统,并对上述电机模型,矢量控制方法及相关硬件设计进行了研究.     

基于串联铁耗模型的感应电机矢量控制分析

在分析感应电机铁耗基础上,给出了感应电机的串联铁耗模型,并提出了一种改进的矢量控制方案。该方案与传统矢量控制方案相比,减小了由于未考虑铁耗所导致的磁链定向误差。最后,通过仿真证明了基于串联铁耗模型的矢量控制方案的有效性。     

PD反馈特征结构配置在最优控制问题中的应用

考虑了二阶线性系统的比例微分(PD)反馈特征结构配置问题以及其在最优控制问题中的应用。基于比例微分特征结构配置参数化方法,将二阶线性系统的最优控制问题转化为一个便于求解的有约束条件的极小值问题,并给出了相应的求解算法。三自由度质量弹簧阻尼系统算例及其仿真结果表明所提算法简单、有效。     

A refined deterministic linear program for the network revenue management problem with customer choice behavior

We present a new deterministic linear program for the network revenue management problem with customer choice behavior. The novel aspect of our linear program is that it naturally generates bid prices that depend on how much time is left until the time of departure. Similar to the earlier linear program used by van Ryzin and Liu (2004), the optimal objective value of our linear program provides an upper bound on the optimal total expected revenue over the planning horizon. In addition, the percent gap between the optimal objective value of our linear program and the optimal total expected revenue diminishes in an asymptotic regime where the leg capacities and the number of time periods in the planning horizon increase linearly with the same rate. Computational experiments indicate that when compared with the linear program that appears in the existing literature, our linear program can provide tighter upper bounds, and the control policies that are based on our linear program can obtain higher total expected revenues. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

固体发动机星形药柱的形状优化分析

为了极大地提高发动机的结构完整性能,利用MSC.Nastran软件的结构优化功能,对星形药柱发动机进行了形状优化分析.探讨了发动机形状优化中位移模式和辅助模型的建立方法,根据发动机的结构和受力特点,建立了星形药柱的平面应变模型,对星形药柱的控制参数进行了灵敏度分析,并在此基础上对星形药柱进行了形状优化.优化结果表明:增大星边夹角和顶弧倒角可有效地缓解应力应变的集中程度.     

基于Fisher线性判别模型的文本特征选择算法

在采用向量空间模型表示方法的文本分类系统中,维数约简是必要的步骤,特征选择方法由于计算复杂度较低而被广泛采用.本文基于Fisher线性判别模型提出了一种新的文本特征选择算法,将其求解过程转换为一个特征项优化组合的问题,避免了复杂的矩阵变换运算.实验表明,该方法与信息增益、卡方统计方法比较,具有较明显的优势.     

一类极点指标与方差指标约束的满意控制

在将极点配置到关于实轴对称的凸多边形区域时 ,总可以用线性矩阵不等式来描述 ,于是对具有状态稳态方差指标、区域极点指标约束的状态反馈系统 ,可以利用 Matlab- L MI工具箱进行求解反馈增益 ,其仿真结果对结论作了说明。     

装甲车辆电传动系统永磁同步电机的设计与仿真

主要对电传动系统永磁同步电机进行了设计和仿真,首先对电传动和所采用永磁同步电动机进行了概述,给出了电机的基本参数要求,并在这些参数基础上对电机结构进行了初步设计,然后运用Simulink对永磁同步电机进行了建模仿真,获得了较为理想的结果。     

Inducing coordination in supply chains through linear reward schemes

Decentralized decision‐making in supply chain management is quite common, and often inevitable, due to the magnitude of the chain, its geographical dispersion, and the number of agents that play a role in it. But, decentralized decision‐making is known to result in inefficient Nash equilibrium outcomes, and optimal outcomes that maximize the sum of the utilities of all agents need not be Nash equilibria. In this paper we demonstrate through several examples of supply chain models how linear reward/penalty schemes can be implemented so that a given optimal solution becomes a Nash equilibrium. The examples represent both vertical and horizontal coordination issues. The techniques we employ build on a general framework for the use of linear reward/penalty schemes to induce stability in given optimal solutions and should be useful to other multi‐agent operations management settings. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2006