重力势能锁止型外骨骼设计及其效能评价

现存的被动式外骨骼存在助力效果不明显等缺陷。基于人体步态特征,提出了将人体行走过程中的重力势能转化为人体抬腿过程中动能的原理,通过弹簧、曲柄滑块机构、棘轮棘爪机构以及链传动机构的组合,设计了一款被动式下肢机械外骨骼,并通过外骨骼动力学分析和生理消耗指数实验测试的方法进行了外骨骼性能评价。动力学分析结果表明,穿戴外骨骼后髋关节峰力矩总量降低了23.43%,髋关节做功总量降低了30.59%,初步验证了外骨骼的有效性。生理消耗指数实验测试结果表明, 穿戴外骨骼对于短距离动作转换未产生显著效果,但在长距离行走和上坡行走中分别降低了8.1%和10.4%的能量消耗。因此,该下肢外骨骼助力性能得到了验证,为相关领域的研究提供了实例化参考。     

Prediction of three-dimensional elastic behavior of filament-wound composites based on the bridging model

This work provides a method to predict the three-dimensional equivalent elastic properties of the filament-wound composites based on the multi-scale homogenization principle.In the meso-scale,a representative volume element(RVE)is defined and the bridging model is adopted to establish a theoretical predictive model for its three-dimensional equivalent elastic constants.The results obtained through this method for the previous experimental model are compared with the ones gained respec-tively by experiments and classical laminate theory to verify the reliability of this model.In addition,the effects of some winding parameters,such as winding angle,on the equivalent elastic behavior of the filament-wound composites are analyzed.The rules gained can provide a theoretical reference for the optimum design of filament-wound composites.     

Multi-objectives nonlinear structure optimization for actuator in trajectory correction fuze subject to high impact loadings

This paper presents an actuator used for the trajectory correction fuze, which is subject to high impact loadings during launch. A simulation method is carried out to obtain the peak-peak stress value of each component, from which the ball bearings are possible failures according to the results. Subsequently, three schemes against impact loadings, full-element deep groove ball bearing and integrated raceway, needle roller thrust bearing assembly, and gaskets are utilized for redesigning the actuator to effectively reduce the bearings' stress. However, multi-objectives optimization still needs to be conducted for the gaskets to decrease the stress value further to the yield stress. Four gasket's structure parameters and three bearings' peak-peak stress are served as the four optimization variables and three objectives, respectively. Optimized Latin hypercube design is used for generating sample points, and Kriging model selected according to estimation result can establish the relationship between the variables and objec-tives, representing the simulation which is time-consuming. Accordingly, two optimization algorithms work out the Pareto solutions, from which the best solutions are selected, and verified by the simulation to determine the gaskets optimized structure parameters. It can be concluded that the simulation and optimization method based on these components is effective and efficient.     

C4ISR系统体系结构设计集成环境

C4ISR系统体系结构设计是系统综合集成的基础.针对C4ISR体系结构框架2.0,分析了体系结构产品的特点,研究了体系结构产品设计工具的分类以及应该具有的功能,提出体系结构产品设计工具的集成框架和基于体系结构核心数据库的数据管理机制,并实现了体系结构产品设计工具以及体系结构设计集成环境.     

基于程序设计类课程的教育技术本科生创新思维培养研究与实践

本文基于ATDE创新教育理论,以程序设计类课程为教学阵地,对教育技术本科生创新思维培养做出了相关探索与实践。创新思维是高级的问题解决活动。培养学生的创新思维更多体现在对学生解决问题的策略应用方面。对此,本文通过给出的案例,从不同角度详细介绍了程序设计类课程对培养教育技术本科生创新思维的实施对策,以期对提高本专业建设做出有益的探索。     

On the uncapacitated K‐commodity network design problem with zero flow‐costs

Extending Sastry's result on the uncapacitated two‐commodity network design problem, we completely characterize the optimal solution of the uncapacitated K‐commodity network design problem with zero flow costs for the case when K = 3. By solving a set of shortest‐path problems on related graphs, we show that the optimal solutions can be found in O(n³) time when K = 3, where n is the number of nodes in the network. The algorithm depends on identifying a list of “basic patterns”; the number of basic patterns grows exponentially with K. We also show that the uncapacitated K‐commodity network design problem can be solved in O(n³) time for general K if K is fixed; otherwise, the time for solving the problem is exponential. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004     

CsLiB6O10晶体Ⅰ型光参量过程中角度调谐研究

根据三波耦合过程中的能量动量守恒,基于非线性晶体的相位匹配理论,利用CsLiB6O10(CLBO)晶体的Sellmeier方程,详细分析了Ⅰ型共线及非共线参变过程中CLBO晶体的角度调谐特性.这对于激光脉冲的激光参量过程的优化具有重要的意义.     

双线性表面建模电大目标RCS仿真

目标的电磁散射特性研究对于实现雷达探测、识别、跟踪目标起着至关重要的作用,而雷达散射截面(Radar Cross Section,RCS)又是体现目标电磁散射特性的一个重要方面.参数曲面能精确模拟目标的几何外形,提高计算精度.采用参数曲面——双线性表面建模,运用物理光学(Physical Optics,PO)法计算电大...     

无人飞艇平台摄像机防振研究

无人飞艇作为理想的信息平台,在预警、反恐、侦察监视和通信等方面发挥着重要作用。而艇载侦察监视设备CCD摄像机受到飞艇发动机振动的影响,会对成像产生消极影响。为此,分析了影响飞艇摄像机的成像质量的因素,采用被动减振的方案,达到了有效克服振动的目的。     

建筑节能初期设计阶段的能耗模拟与分析

针对建筑节能初期设计阶段,采用建筑环境设计软件Ecotect对某节能示范楼外窗遮阳情况进行模拟分析,得到各朝向外窗的遮阳形式以及大小设计范围,为下一阶段包括外遮阳形式,构造尺寸和各朝向房间的窗墙比、外窗材料选择提供了设计参考.