AC回转工作台式五轴机床后置处理器研究与实现

针对具有AC回转工作台机床结构的五轴联动数控机床后置处理,分析了其中重要的五自由度机床运动轨迹坐标变换;并论述了相应数控系统SIEMENS 840D所特有的钻削循环类非标准指令的后置处理方法;基于此开发出的后置处理程序的正确性通过在BV-100机床上某叶轮样件的加工得到了验证.     

经济型五轴数控机床后置处理系统研究与应用

在双转台五轴数控机床结构的基础上,通过分析机床结构坐标系和CAM加工坐标系的关系,建立其机床加工刀头运动轨迹的数学模型,推导出该类型机床的后置处理转角计算公式和坐标转换计算公式。根据推导结果,在UG/PostBuilder通用后置处理器的基础上,针对不同类型五轴联动数控机床选配特定数控系统,设定机床参数、程序和刀轨参数、NC代码格式设置,编制了双转台式五轴数控机床的专用后置处理程序,经实际加工验证可以满足经济型五轴联动后置处理的要求。     

基于PMACⅡ开放式五轴数控机床的研究

介绍了基于PMACⅡ开放式五轴联动机床的硬件结构和PMACⅡ运动控制卡及控制原理,并根据机床结构给出针对该结构的五轴后置处理算法.     

基于UG的五轴联动数控加工技术在吹塑模具的应用

五轴联动加工应用越来越广泛,但编程和操作都较复杂。针对饮料瓶吹塑模具的结构参数以及模具的加工精度相关要求,提出在粗、半精与精加工时的多轴加工工艺策略。然后,阐述某一型号的五轴联动机床的后置处理时应进行机床坐标系关系分析,通过机床控制系统生成不同数控程序。最后,对该机床专用后置处理器的开发过程进行详细分析,生成机床所需的NC代码,可实现吹塑模具的加工质量、精度、加工效率大大提高。     

摆头转台加工中心五轴联动加工的后置处理与仿真验证

在对东芝BTU-14五轴加工中心结构特性、东芝TOSS999控制系统特性以及五轴联动加工编程特点进行分析的基础上,提出其五轴联动加工的后置处理算法。在该算法基础上,利用VisualC++6.0开发出单独的后置处理程序,将加工刀轨的刀位文件处理生成东芝格式的G代码文件。为了验证后置处理程序的正确性,利用数控仿真软件Vericut 7.0建立机床的仿真模型,对后置处理程序生成的G代码文件进行仿真。最后实际加工了一个测试样件,证明了后置处理程序的正确性。     

五轴联动数控机床的后置处理方法

后置处理是数控编程的重要环节 ,它的作用是将 CAM系统生成的刀轨文件转化为机床的加工代码。五轴联动的后置处理涉及到刀位文件的转角计算和坐标变换计算 ,坐标转换关系比较复杂 ,本文研究了立卧两种状态的五轴联动数控机床的后置处理 ,在分析了机床坐标系和工件坐标系关系的基础上 ,推导了坐标变换公式 ,并开发出了相应的后置处理软件 ,其结果满足五坐标联动后置处理的要求     

基于CAXA制造工程师的哈默C40U机床程序后置处理模块优化

针对哈默C40U机床的结构及加工特点,对CAXA制造工程师中的五轴加工后置功能模块进行参数优化设置,使后置生成的加工程序更有针对性,特别是对于哈默C40U五轴联动机床中最重要的工作台旋转、倾斜及刀具进退刀、换刀、定位等复杂动作实现了更加安全地衔接。并利用实例证明,经定制处理后的CAXA制造工程师五轴加工后置处理模块,对哈默C40U双转台机床的加工适应性更好,安全性更高。     

双转台五轴数控机床后置处理算法研究

通过分析双转台五轴数控机床坐标系和CAM加工坐标系的关系。建立其数学模型。进行机床运动学求解。推导出该类机床后置处理转角计算公式和坐标转换计算公式。根据推导结果。开发了UCP600五轴数控机床专用后置处理程序，经实验验证可以满足五轴联动后置处理的要求。     

叶片数控加工后置处理及仿真技术的研究

随着计算机技术的不断发展,先进的CAD/CAM软件技术已广泛的应用于现代数控技术中。通过运用UG这款具有模具数控加工方面强大功能的软件,结合典型复杂曲面类零件叶片的加工工艺,探索出了多轴联动相结合的加工方法。同时经过对机床结构与构建机床运动学方程的分析,详细的推导出机床的后置处理算法,并基于以上算法,研发了机床专用后置处理程序。实现了叶片数控加工程序的编写、机床专用后置处理程序算法的计算,并以3D仿真软件VERICUT进行仿真加工。采用计算机仿真加工来评估加工工艺方案和机床仿真及碰撞检查,以及后置处理和加工程序生成等技术,实现了叶片从设计到加工的无缝集成,对提高叶片设计、加工质量和效率及降低叶片生产制造成本有着十分重要的意义。     

特殊双转台结构五轴联动加工中心后置处理算法研究

针对非传统笛卡尔坐标系统的特殊双转台结构五轴联动加工中心,通过研究机床结构及其后置处理算法,推导出转台运动角度计算和直线坐标变换公式,开发了其后置处理器并集成到UG软件中,利用DMU 70eV五轴联动加工中心进行了复杂工件加工实验,验证了该算法正确性,实现了复杂零件产品的CAD/CAM一体化无图纸设计与制造.     

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...     

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.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.