工业4.0下的安全防护围栏成型装配工艺

针对机械设计中零件模块化快速成型、零件特征辨识与装配困难的问题,借鉴工业4.0中端对端集成设计理念,以安全防护围栏的指向性设计与装配为研究对象,开发安全防护围栏智能设计与装配系统。该系统基于嵌入式机械通信协议(machine-to-machine,M2M),将零件快速成型与定点装配有机结合,采用程序驱动参数化方法和对象连接与嵌入(object linking and embedding,OLE)技术,将特征装配(FAT)与数据流链(DFC)结合判定零部件装配顺序,二维工作界面给定约束,在Solid Works中生成装配体模型,产生BOM列表,实现安全防护围栏快速设计与装配。     

基于装配定位优先级的并联结合面误差建模

分析了并联结合面在装配定位优先级意义下装配误差的形成机理与计算方法。针对常见的平面结合面与圆柱结合面,分析了误差形成和装配精度失效的原因,采用小位移旋量(SDT)法描述了误差变动。针对并联结合面间位姿变动的相互影响,定义了装配定位优先级的概念,并详细分析了并联结合面装配定位优先级的判定依据。根据装配定位优先级确定了并联的各结合面误差组成及计算方法。列举了常见的并联结合面形式,并以一组常见并联结合面的装配误差分析为例,验证了该方法的可行性,为装配体误差分析、零件精度设计、装配成功率计算等提供了借鉴。     

飞机防护瓦智能装配系统研究

针对当前飞机防护瓦装配型架功能单一、自动化程度低、装配效率低、装配过程可控性差等问题,研究了一种飞机防护瓦智能装配系统.该系统集成了拉压力自适应控制技术、模块化技术.基于模块化理念将防护瓦智能装配系统划分翻转组件、保型组件、移动组件和拉压组件.拉压组件采用力与位移的自适应控制算法,保证了拉压力大小与方向的精确性.结果表明:智能装配系统实现了全机防护瓦集成装配,保证了稳压过程方向与大小的精确性,提高了装配效率.     

基于JSS矩阵的装配精度分配方法

采用小位移旋量描述结合面误差,分析了典型结合面的误差传递属性。定义了结合面的信息集成表达符号,结合多色集合理论,建立了描述装配关系、结合面类型、结合面误差传递属性的结合面符号矩阵,进而提出了装配误差传递路径的搜索方法。分析了结合面间的关系对误差传递的影响,建立了结合面的实际误差传递属性矩阵,获取了各误差分量的传递路径,明确了影响装配体精度的关键误差分布。根据多体运动学原理建立了装配体误差模型,结合装配体精度要求进行了结合面精度分配,进而实现了结合面相应几何要素的精度分配。为正向公差设计与装配过程精度控制提供了依据。最后通过实例分析,验证了该方法的可行性与实用性。     

基于JSS矩阵的装配误差传递路径求解方法

采用小位移旋量描述结合面误差,分析常见装配结合面的误差传递属性。定义包含工程语义的结合面符号用以描述结合面类型和配合关系。结合多色集合理论,建立可描述装配关系、结合面类型和误差传递属性的结合面及误差关系围道矩 阵-结合面符号(Joint surface symbols,JSS)矩阵。提出基于JSS矩阵的装配误差传递路径搜索方法,建立结合面实际误差传递属性矩阵,讨论获取各误差分量传递路径的方法。针对并联误差传递路径的不确定性问题,提出以精度最高作为判别有效误差传递路径的依据,基于雅可比旋量理论建立误差模型,获取与装配体精度要求相关的误差分量的有效误差传递路径。以一个典型装配体的误差传递路径求解为例,验证了论文研究方法的可行性与实用性。     

新工艺配刮的结合面抗振耐磨机理

利用新的刮研方法和复压技术，制造加工机床固定结合面是继机床主轴轴承采用预紧技术后，又一提高机床刚度的装配技术。新装配技术包括振动研点的新刮研法和对刮削完的表面重复加压—称复压技术。这两项技术应用在固定结合面配刮上，可使接触变形为零，提高机床整体刚度，...     

视觉与力觉结合的卫星部件机器人装配

针对卫星特殊部件的装配需求,为了使机器人具有适用不同工况的柔性并在卫星多变的装配工况中获得较高的应用效率,本文研究视觉引导与力反馈控制下的机器人装配技术,给出一种视觉与力觉结合的机器人装配方案:在装配孔位安装辅助销钉,通过视觉引导将部件引导至销钉的锥面导向范围内,而后在销钉导向下对机器人采用力反馈控制,实现工件的准确装配到位。采用红外相机结合合作靶标的方式实现稳定地视觉识别与目标定位,设计了探针式测量工具,并给出测量方法,实现了目标点位的柔性便捷测量。给出了一种已知空间对应点对条件下,求位姿变换矩阵及机器人目标位姿的计算方法。采用力/位混合控制方法实现柔顺销钉导向控制。实验结果表明:装配对应孔位的测量匹配误差在2.9 mm以内,机器人在视觉引导下,可以将工件运送至销钉的导向范围内,并在销钉导向及力反馈控制下将工件准确装配到位,力控制阈值为30 N。证明了本文所采用的技术可以满足卫星部件装配的工程实施要求。     

多公差耦合装配结合面误差建模与公差优化设计

以装配结合平面为研究对象,分析多种公差耦合情况下零件间装配结合面误差建模和公差优化设计问题。采用小位移旋量(Small displacement torsor,SDT)描述公差,针对不同类型公差建立零件平面误差模型,通过蒙特卡洛模拟法获得装配平面误差变动分量的实际变动区间带宽,通过响应面法建立误差变动分量实际变动区间带宽与公差间的显式函数关系;建立包含零件加工误差与装配过程误差的装配结合面综合误差模型。将该方法扩展应用于复杂装配体的装配误差建模中,实现了在设计阶段对装配精度的预测。以加工成本为目标,装配精度可靠度为约束,进行零件公差的优化设计。以一典型产品精度设计为例,验证了用该方法预测装配精度和优化零件公差设计的可行性与实用性。     

零件加工与装配对机器机械结构振动性能的影响

本文根据加工质量及装配质量对机械结合面刚度和阻尼的影响。分析了零件加工及装配对机器机械结构振动性能的影响。     

一种有效的螺纹固定结合部有限元建模方法

针对结合面压力不均匀分布对结合部建模精度存在影响,给出了一种基于结合面压力不均匀分布的螺纹固定结合部动力学建模方法.首先,利用Ansys对施加预紧力的装配体整机进行静力学分析,提取结合面处的节点、单元信息及压力分布,基于节点间距离最短的原则对上、下结合面中的节点进行匹配,在匹配好的两节点间建立Matrix27刚度、阻尼...     

Characteristics analysis of the developed surface modification technologies to improve the anti-corrosion performances for offshore equipments

In this study, we carried out the characteristics analysis and experiment research of the developed technologies based on surface modifications to enhance the anti-corrosion performance of offshore equipments. The developed technologies are the dipping method to generate super-hydrophilic surface which is then treated to be super-hydrophobic using chemical deposition and lubricant impregnation, and the spray coating method to generate super-hydrophobic surface. It is well-known that the super-hydrophilic and super-hydrophobic surfaces have good anti-corrosion performance. However, the mechanical properties should be maintained. We have verified the anticorrosion performance through the salt spray test and the measuring contact angle. And, we have evaluated the mechanical characteristics such as hardness. As the results, the dipping and the spray coating methods improved the anti-corrosion performance maintaining its mechanical properties at the same coating thickness of about 80 nm.

     

风机叶片用涂层的抗冲蚀性能的研究

针对风机叶片用涂层的抗冲蚀性能进行了研究,从磨损原理入手,分析研究了等离子喷涂涂层和表面粘涂涂层的抗冲蚀性能。采用NIWC35涂层和陶瓷耐磨修补剂（11680）涂层,对涂层结合强度、硬度、显微结构及抗冲蚀性能进行了研究。试验结果表明,等离子喷涂涂层在低角度下的冲蚀明显低于高角度下的冲蚀;而耐磨修补剂（11680）涂层从冲蚀情况看,Al1O3与树脂的粘结状况是良好的,在冲蚀率上,高角度下耐剖蚀性能比低角度下好。     

The tribological behavior of diester-containing polysulfides as additives in mineral oil

The diester-containing polysulfides were synthesized and their anti-wear (AW) and friction-reducing behaviors as additives in HVIW H150 base oil were evaluated using a four-ball tester. The copper corrosion test was conducted to identify their anti-corrosion property. The nature of the film formed in the rubbed surface was investigated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Based on the experimental results, diester-containing polysulfides show good anti-corrosion properties and excellent AW abilities similar to that of ZDDP. The results of XPS analyses illustrate that an S-containing inorganic layer, generated by the reaction of diester-containing polysulfides with the metallic surfaces, mainly contains sulfate, sulfite and little sulfide, and there exists a polymer film protective layer over the inorganic layer surface.     

Evaluation of surfaces complementarity based on high definition metrology

The gap between two mating surfaces has a direct influence on sealing performance. However, traditional surface metrology rarely characterizes the gap between two mating surfaces. To solve this problem, a novel concept of surfaces complementarity is proposed in this paper. Surfaces complementarity measures how well two rough surfaces fit into each other. To make this concept applicable in engineering practices, a virtual assembly algorithm is developed. The automatic virtual assembly algorithm aligns the mating surfaces by maximizing the overlap ratio of the surface masks. Then, a sum surface which is complementary to the surface gap is constructed to represent the mating states. The top surface of a cylinder block and corresponding cylinder head surface measured by high definition metrology is mated by the virtual assembly algorithm. The differences of functional parameters between the mating surfaces and the sum surface are discussed thoroughly. Due to surfaces complementarity, parameters of the sum surface has a certain deviation from expected combined parameters from two individual surfaces. A case of square surface shows the practical application potential of the virtual assembly algorithm to optimize the sealing performance of the mating surfaces.     

纳米碳化硅化学沉积技术在汽车零部件表面上的应用

纳米碳化硅与金属合金在汽车零部件表面进行化学沉积．实现对其表面的改性．达到耐磨、延长疲劳寿命、提高承受冲击载荷性能和防腐蚀性能的目的。     

中压主汽门阀盖螺栓断裂原因分析

中压主气门阀盖螺栓在运转两年后出现多根断裂,通过观察和分析20cr1Mo1VnbTiB高温螺栓断口的宏观及微观形貌,检验化学成分、测试力学性能,显微组织检验等方法,分析螺栓断裂原因。力学性能和化学成分符合要求,但螺纹根部粗糙度比较大,硬度为316 HBW2．5／187．5超过标准中规定的硬度252～302HBW上限值,金相组织是回火索氏体。分析结杲表明,螺纹根部粗糙,引起局部应力集中,全相组织不符合要求,硬度超过标准中的规定,晶粒粗大等是螺栓断裂的主要原因。在生产中,要加强高温紧固件性能检测,遵守拆装要求,定期喷涂防腐介质,以防此类事故发生。     

CAFD中的夹具快速装配技术研究

近年来CIMS中的CAD、CAPP、CAM技术得到了长足的进展 ,然而基于CAD模型的夹具自动设计的研究还相对薄弱 ,尤其是夹具的自动装配技术。本文引入了有效表面和有效路径的概念 ,建立了快速装配模型 ,给出了功能结构及详细的夹具装配算法流程 ,为组合夹具的快速装配提供了一种切实可行的方法     

Robotic automatic assembly system for random operating condition

A vision guided tabletop robotic assembly system is constructed for the random environment automatic assembly purpose. The distributed control structure is designed for this assembly system. A PC is specified as the central control unit for machine vision operation and the harmonization of At89c51 distributed control unit for each axis. The machine vision is introduced to search the locations and measure the size of the assembly parts in the robotic workspace. Then, the central controller commands the robot to pick the part sequentially based on the specified program to complete the automatic assembly process. The model-free fuzzy sliding mode control scheme is embedded in each joint micro controller for simplifying the model based control problem. The central control unit PC communicates with each joint controller by network communication. This assembly system is implemented on a 3 DOF SCARA robot. The experimental results show that the robotic motion control performance is good enough for assembling work; the vision pattern classification and assembly motion paths planning and monitoring are exactly executed by the central control unit. The goal of this robotic random assembly operation is achieved with the appropriate integration of robotic motion control, machine vision, sensor and assembly force detecting techniques.     

大型管形座的装焊

通过对大型管形座结构的分析,着重阐述了下料、拼板、成形、组装和焊接过程中将要出现的尺寸不准、焊接变形及产生应力等问题的对策,制订了相应的工艺措施,确保组装焊接的质量,具有一定的推广价值。     

大型管形座的装焊

通过对大型管形座结构的分析,着重阐述了下料、拼板、成形、组装和焊接过程中将要出现的尺寸不准、焊接变形及产生应力等问题的对策,制订了相应的工艺措施,确保组装焊接的质量,具有一定的推广价值。