小型飞机起落架双余度电动收放系统设计

起落架如何实现全电收放一直是全电飞机发展过程中的技术难题.为此,针对小型飞机起落架,研制了一种双余度电动收放作动筒.该电动作动筒具有直线收放、到位时锁定、收放时解锁和故障时应急放的功能.设计了一种电动收放系统双余度控制策略,并对其进行论述和分析.最后,通过试验对电动收放系统的功能和性能进行了验证,试验结果表明电动收放系统满足设计要求.     

某无人机起落架电动收放作动筒电机选型

通过对起落架电动收放作动筒工作原理进行分析计算,确定起落架电动收放作动筒电机选型的主要技术参数,通过计算和校核选择出适合该无人机电动收放作动筒的电机型号和参数。     

一种起落架收放作动筒建模及参数调试方法

对一种典型飞机的起落架收放作动筒内部阻尼特性进行分析,提出了一种收放作动筒详细建模的方法。选择某速度下起落架收上工况,将收放作动筒模型放入起落架收放系统中进行联合仿真和参数调试,分析了收放作动筒内部阻尼特性对收放时间的影响。同时将仿真结果和试验结果进行对比,验证了收放作动筒建模的合理性。提出的收放作动筒建模及参数调试方法具有普适性,能够为飞机起落架收放性能仿真提供参考。     

某民用飞机主起上位锁开锁压力过大问题分析与解决

在某新型民用飞机起落架收放研发试验中,发现主起落架上位锁开锁压力过大的问题,针对问题进行了理论分析,认为主起落架放下时,油液同时到达收放作动筒和上位锁开锁作动筒,但由于收放作动筒油液作用面积大于上位锁开锁作动筒油液作用面积,使得收放作动筒在上位锁开锁前将力施加到上位锁上,并通过试验验证了此分析结论的正确性,为改进设计方案提供了试验依据。     

一种液压活门的设计改进

该文简要介绍了我公司某产品上液压牧放作动筒在收起时,回油阻力较大,收起速度太慢的原因分析,以及对与收放作动筒相连的液压协调活门的设计改进.通过较小改进,效果颇佳,液压系统供油时,收放作动筒收放正常,阻尼和收放速度较均为理想.     

四余度舵机典型故障分析

某型四余度电液舵机是飞机平尾操纵系统的关键部件。首先将四余度舵机划分为电动液压部分组合件、带平板阀的配油装置组合件、液压作动筒和伺服控制系统等4个功能模块，分别对其进行典型故障分析，并分析了各种故障情况对系统性能的影响。     

某型起落架收放作动筒故障模式影响及危害性分析

运用故障模式影响及危害性分析方法对飞机起落架收放作动筒进行分析,识别其潜在的故障模式,并评估各故障模式的危害度,最终确定可靠性关键产品,提出相应的改进措施,指导产品设计。     

某型飞机作动筒常见故障分析及维护

作动筒是飞机液压系统的主要执行附件,影响着飞机起落架、轮舱门、襟翼及减速板收放等多方面的性能。本文针对海军某型飞机的不同作动筒在使用和维护时的常见故障展开讨论,无锁作动筒常存在活塞杆卡滞不动作、运动迟缓、速度不均及爬行现象,而带锁作动筒还存在上锁、开锁不灵活或者上锁不可靠等问题。本文针对上述故障原因进行分析,并提出相应的排除方法。此外,在对作动筒外场维护时,针对上述故障,要定期检测作动筒收放速度,做好清洁,防止异物侵入和查看外漏部分等。期望能为其他机型作动筒的故障分析和维护提供参考。     

一种电静液作动器可靠性的GO分析设计方法

针对提高复杂机电液一体化产品-飞机电静液EHA可靠性的问题,研究了基于GO法的EHA可靠性计算方法,提出了一种电静液作动器EHA可靠性的GO分析设计方法,完成了具有多组件余度参数的EHA作动器GO图和GO运算,推导了其可靠度计算公式,得出了高可靠性EHA设计的相关理论,给出了GO法应用于EHA余度设计的新思路。设计算例表明,这种基于GO法的EHA可靠性分析设计方法计算精确,能很快得出较优余度设计参数,是一种可行的系统性分析设计方法。     

某型飞机起落架收放作动筒自发伸出现象分析

该文针对某轻型飞机起落架收放作动筒活塞杆出现的自发伸出现象进行分析,通过分析及试验明确了作动筒伸出的原因。该文对采用液压锁锁定的液压系统的热膨胀现象有一定的借鉴性。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.