Stifness modeling and analysis of a novel 4-DOF PKM for manufacturing large components

Faster response to orientation varying is one of the outstanding abilities of a parallel kinematic machine（PKM）.It enables such a system to act as a reconfgurable module employed to machine large components effciently.The stiffness formulation and analysis are the beforehand key tasks for its parameters design.A novel PKM with four degrees of freedom（DOFs）is proposed in this paper.The topology behind it is 2PUS-2PRS parallel mechanism.Its semianalytical stiffness model is frstly obtained,where the generalized Jacobian matrix of 2PUS-2PRS is formulated with the help of the screw theory and the stiffness coeffcients of complicated components are estimated by integrating fnite element analysis and numerical ftting.Under the help of the model,it is predicted that the property of system stiffness distributes within the given workspace,which features symmetry about a certain plane and is also verifed by performing fnite element analysis of the virtual prototype.Furthermore,key parameters affecting the system stiffness are identifed through sensitivity analysis.These provide insights for further optimization design of this PKM.     

气动计算软件集成系统中的远程控制

随着我国航空航天技术的飞速发展,气动计算软件集成技术日趋成熟,但用户在并行计算中需要手动输入的操作较多。鉴于此,通过编程开发了基于TCP／IP协议的FTP客户端应用程序,实现了对网格文件的信息采集、过滤并将其和参数、脚本文件等批量自动上传的功能。根据批处理文件中的命令,调用Windows平台自带的客户端Telnet,向远程集群管理节点发出命令,远程启动服务器集群的并行计算任务。最后,在客户端实现了远程控制服务器集群上的计算流体力学软件Fluent进行并行计算。结果表明：使用该远程控制系统能够减少用户输入操作,提高计算效率,保证数据的实时更新。     

某型教练机机载天线与雷达罩的射线入射角的计算

随着现代高科技的发展,雷达大量应用于飞机、导弹、航海等领域．雷达罩的运用也日趋广泛。本文通过曲线拟合等一些数学分析方法,运用MATLAB工具,经过分析、编程、计算．最后得到机载天线与雷达罩的射线入射角,通过入射角的大小可判断此雷达罩是否符合要求。     

Numerical study of intrachamber processes dynamics at nozzleless solid propellant rocket engine actuation

The results of the comprehensive numerical analysis for dynamics of intrachamber processes that appear at nozzleless solid propellant rocket engine (SPRE) actuation are presented. A complete cycle of rocket engine operation is analyzed. We solve a conjugate problem involving the igniter actuation; heating, ignition and following combustion of a solid propellant charge; a combustion product flow in the combustion chamber; depressurization of the combustion chamber, and the subsequent motion of the rocket engine blank; variation of the combustion surface geometry at the expense of the gradual and nonuniform burnout of solid propellant web.     

Fault self-repair strategy based on evolvable hardware and reparation balance technology

In the face of harsh natural environment applications such as earth-orbiting and deep space satellites, underwater sea vehicles, strong electromagnetic interference and temperature stress,the circuits faults appear easily. Circuit faults will inevitably lead to serious losses of availability or impeded mission success without self-repair over the mission duration. Traditional fault-repair methods based on redundant fault-tolerant technique are straightforward to implement, yet their area, power and weight cost can be excessive. Moreover they utilize all plug-in or component level circuits to realize redundant backup, such that their applicability is limited. Hence, a novel selfrepair technology based on evolvable hardware（EHW） and reparation balance technology（RBT） is proposed. Its cost is low, and fault self-repair of various circuits and devices can be realized through dynamic configuration. Making full use of the fault signals, correcting circuit can be found through EHW technique to realize the balance and compensation of the fault output-signals. In this paper, the self-repair model was analyzed which based on EHW and RBT technique, the specific self-repair strategy was studied, the corresponding self-repair circuit fault system was designed, and the typical faults were simulated and analyzed which combined with the actual electronic devices. Simulation results demonstrated that the proposed fault self-repair strategy was feasible. Compared to traditional techniques, fault self-repair based on EHW consumes fewer hardware resources, and the scope of fault self-repair was expanded significantly.     

基于Probit模型的航空差旅管理市场分析

研究分析企业和差旅管理公司的哪些因素会对差旅管理业务的选择产生影响,帮助差旅管理公司明确企业的差旅管理偏好,从而推动中国航空差旅管理市场的发展.针对航空差旅管理市场的现状,在对50家企业进行问卷调查后,通过Probit模型得出10个因素对企业选择差旅管理业务的影响程度,其中“现金流量”、“资金结算手段”、“增值服务种类”和“政策与系统的匹配度”4个因素具有显著性.最后,根据实证结果对企业和差旅管理公司提出相应的建议.     

基于CCSDS MO服务参考模型公共服务接口设计

为提高飞行器任务运控系统的可重用性和可扩展性,对基于CCSDS(空间数据系统咨询委员会)MO(任务运营)服务参考模型的系统设计和实现方法进行了研究。针对MO服务参考模型的核心服务层,以我国飞行器任务运控系统的需求为出发点,在分析了MO服务参考框架、MO服务定义、运控功能服务定义和公共服务组成的基础上,对MO各公共服务的接口进行了分析与设计。采用面向对象方法学、设计模式等理念,设计并实现了相关公共服务接口。通过向运控功能服务提供API(应用程序接口),可以支持系统应用层开发。这为建立符合CCSDS MO服务参考模型的飞行器任务运控系统,并实现系统的可扩展性和可重用性提供了支持。     

轮胎和缓冲支柱压力对摆振特性的影响

阐述了摆振分析的基本思路,分析了轮胎和缓冲支柱压力对摆振特性的影响,并结合某起落架计算比较了不同轮胎及缓冲支柱压力下的摆振特性。研究表明:当两者压力降低时,摆振临界阻尼均减小,有利于防摆;反之,摆振临界阻尼均增大,不利于防摆;但在两者压力变化的百分比相同的情况下,轮胎压力变化比缓冲支柱压力变化对摆振特性的影响更明显。     

通用的航电系统总线接口仿真平台的设计和应用

针对当前航电系统仿真器的缺点,提出了一种通用的航电系统总线接口仿真平台的设计思想,通过建立仿真数据库,从待仿真的航电系统设备中的接口信息抽象出属性和行为,然后用数据库的方式来描述,实现了仿真软件和仿真对象的分离,从而使该仿真平台具备了通用性和灵活性。该仿真平台已经在某型机航电系统地面联试中得到了应用。     

一种悬挂物兼容飞机航电与武器总线的设计方法

在某悬挂物作为通用系统挂装不同型号飞机时,由于不同型号飞机对该悬挂物采用航电和武器两种不同的总线通信方式,导致该悬挂物不能兼容挂载多型飞机。本文针对现有的总线应用情况,提出了一种悬挂物可兼容飞机不同总线通信方式的设计方案,并给出了方案的具体实现方法。