基于自然方程式的平面四杆机构的综合

在连杆曲线以其特征参数分类的基础上,利用其特征参数的自然方程式,将创成曲线与理想曲线一致程度的判定问题,归结为曲线上的特征参数及自然方程式的一致程度的判定,进而用此方法进行了曲线创成机构综合,充分显示了该方法的有效适用性.     

用快速傅里叶变换进行球面四杆机构连杆轨迹综合

根据给出的球面四杆机构连杆轨迹的数学模型,借助傅里叶级数这一数学工具,对连杆轨迹的谐波成分进行理论分析,发现连杆轨迹的谐波成分与其相应转角函数谐波特征参数和机构尺寸参数的内在联系。确定球面四杆机构的基本尺寸型,在此基础上建立包含600余万组机构基本尺寸型的球面四杆机构连杆轨迹的谐波特征参数数值图谱库。利用傅里叶级数理论建立球面四杆机构处于空间任意位置时连杆曲线的数学方程,推导出计算机构的实际安装尺寸、连杆上点的位置和机构安装尺寸参数的理论计算公式。利用建立的谐波特征参数数值图谱和推导的理论公式解决了球面四杆机构的轨迹综合问题,最后给出算例证明本方法的可行性。     

基于小波特征参数的平面四杆机构轨迹综合方法

小波分解可以在不同尺度下对函数曲线的特征进行提取,基于该理论,首先,对平面四杆机构连杆轨迹曲线进行小波分解,利用归一化处理方法提取轨迹曲线的小波特征参数,给出了平面四杆机构连杆轨迹曲线的小波特征参数近似描述方法。进而结合数值图谱法,将11维非整周期轨迹综合问题转换为6维机构尺寸型检索问题,同时建立包含3 004 281 900组平面四杆机构的机构尺寸型数据库。根据轨迹曲线小波特征参数的特点,利用多维搜索树,将各相对转动区间内的机构尺寸型进行分区,建立索引关键字数据库。从而通过比较给定轨迹曲线小波特征参数与索引关键字,查找并提取目标机构所在叶子结点中机构尺寸型的小波特征参数,建立自适应图谱库。在此基础上,根据给定设计要求的小波特征参数与自适应图谱库中的小波特征参数的相似程度,检索出满足设计要求的机构尺寸型。再根据理论公式计算目标机构的实际尺寸及安装位置,实现平面四杆机构非预定相对转动区间轨迹综合问题的求解。最后,利用小波特征参数法对滚压包边设备的滚轮进给机构进行设计,验证本方法实用性和有效性的同时,为传统滚压包边提供新的思路。     

影响双曲柄铰接五连杆机构连杆曲线的因素

介绍了铰接五连杆机构的连杆曲线的求解方法，分析了影响铰接五连杆机构连杆曲线的因素，绘出了几种特殊的铰接五连杆机构的连杆曲线，并简要介绍了铰接五连杆机构的应用前景。     

基于形状谱的平面四杆机构神经网络轨迹设计法

提出用图像形态学与神经网络相结合的方法进行平面四杆轨迹机构的优化设计。利用数学形态学结合图像处理，提取平面连杆曲线的形状谱特征参数，并构建曲线形态的识别、比较方法；再在曲线识别比较的基础上，提出了平面四杆轨迹机构的神经网络综合法，并用实例验证了方法的有效性。     

Fourier变换在空间连杆机构轨迹综合中的应用

从空间连杆机构连杆曲线的Fourier级数表达式入手,解决了空间连杆机构连杆曲线的数学描述问题.通过分析找到了连杆曲线谐波特征参数与连杆转角算子谐波特征参数之间的内在联系,在此基础上给出了轨迹综合的步骤,为解决空间连杆机构的轨迹综合问题提供了一个新的思路.最后通过解决球面四杆机构轨迹综合问题,证明了本方法的有效性.     

基于模糊论方法的连杆曲线计算机识别

复演轨迹法一直被认为是进行连杆机构设计的一种高效、简便的设计方法，但传统图解法的效率和精度都很低，所以基于复演轨迹法的思想，对平面四杆机构设计进行了研究：首先建立了平面四杆机构连杆曲线及其特征参数的数据库；其次，参照预期曲线的特征，采用模糊数学方法中的λ截集法对曲线进行识别，找出一条或几条与预期曲线相似的连杆曲线。该方法不仅具有较高的识别精度，并能实现设计的多解。     

一种特殊的直线轨迹连杆机构

利用拐点圆概念和对称连杆曲线的特性,导出一个简单的方程式.根据这个方程式只需选定曲柄和机架的长度,即可得到一系列能够产生带有较长直线段对称连杆曲线的铰链四杆机构.还可以得出直线段的长度、方位,并满足曲柄存在条件.把它用作前置机构,综合实现近似间歇运动的六杆机构,效果甚佳.     

四杆直线导向机构尺度综合的新方法

基于图象识别中的Ｈｏｕｇｈ变换,提出了四杆直线导向机构尺度综合的Ｈｏｕｇｈ变换方法,建立了连杆曲线特征参数数据库,并用一个实例对该方法进行了验证。     

用谐波理论和快速傅立叶变换进行五杆机构的轨迹综合

从谐波理论的角度出发,采用平面曲线的快速傅立叶变换,可得到由谐波成分表示的任意五杆机构连杆轨迹的数学描述;应用归一化处理,可将形状、大小、方位、偏移各异的连杆曲线统一到相同的机构特征参数下,从而揭示出各类曲线与机构尺寸型及两输入构件初始角度之间的内在联系。本文首次提出了求解实际机构各参数的数学公式,使利用各种驱动类型和不同定传动比的五杆机构特征参数数值图谱进行五杆机构轨迹综合更为有效。     

平面四杆机构的定性和定位轨迹综合

提出一种直接按轨迹定性要求中的曲率半径误差和直线度误差、圆弧段或直线段长短等定量要求进行定性综合的新方法。将舍有直观几何特性的轨迹曲线斜率角和曲率半径共同作为特征参数建立平面四杆机构连杆曲线的计算机数值轨迹图谱，设计了轨迹的圆弧度和直线度的评价模型，使不必增加附加坐标点即能根据所需的直线或圆弧要求直接进行定性综合，提出了根据斜率角反求轨迹曲线及结合最小二乘法进行间接的定位轨迹综合。两类综合都具有较高的综合速度．     

小波分析在平面四杆机构轨迹综合中的应用研究

将小波多分辨分析理论应用于提取连杆轨迹特征参数并以此构造连杆曲线图谱库,建立了相应的轨迹评价和轨迹复演模型。所提取的特征参数保留了相对斜率角曲线的仅与所取基点有关,与轨迹曲线方位及缩放比例无关的特性。本法减少了图谱数据库的数据冗余、提高了机构综合检索速度。通过与最小二乘距离对比表明本法仍然具有很好的检索排序效果,说明了小波分析可以有效地应用于连杆轨迹的综合课题。     

Proposals for finite 5-dimensional atlases for all planar 4-bar linkage coupler curvesVorschläge für endliche 5-dimensionale atlanten von koppelkurven aller ebenen viergelenkgetriebe

The paper seeks to extend earlier work that makes proposals for an atlas of curves traced by coupler points on crank-rocker linkages. We now examine ways of providing atlases for coupler curves of other 4-bar linkages. Provided that every family of similar movable quadrilaterals are included it is found that, as a further consequence of Roberts' cognate theory, it is sufficient to confine attention to coupler points that lie on or within boundaries that demarcate half the area bounded by two arcs having centres at the coupler bearings. For non-Grashof linkages only one quarter of this area is needed.This leads to an alternative way of providing an atlas of curves traced by coupler points of crank-rocker linkages.     

连杆平面上的标志方向及特殊重合点

定义连杆机构中连杆平面上的若干标志方向及特殊重合点,考察特殊重合点的连杆曲线,分析连杆一般平面运动中牵连运动与相对运动的相位关系,进一步揭示了连杆曲线的变化和分布规律。     

Proposals for a finite 5-dimensional atlas of crank-rocker coupler curvesVorschlagen für ein endlich funfdimensional Kurbelschwingen Koppelkurvenatlas

The coupler curves traced by planar 4-bar crank-rocker linkages are examined with the objective of providing guidelines for a new awareness survey. It is found that the coupler points chosen by Hrones and Nelson[1] in the best known atlas of this kind leads to some avoidable duplication and omissions. It is concluded that coupler points should be confined to a circle on the coupler plane having centre on the coupler-rocker bearing and radius equal to the distance between coupler bearings. Five non-dimensional variables are proposed, three of which are discussed in more detail in earlier work[6].     

Triangular nomograms for symmetrical coupler curvesHoмoгpaммa тpeyгoльнoй фopмы длы cиммeтpичныч мaтyнныч кpaивычNomogrammes triangulaires pour les courbes symmetriques

Triangular nomograms have been constructed as a simple means of finding symmetrical coupler curves of the crank-rocker linkage. A nomogram of this kind has been presented by the author of this article during a Conference of the Institution of Mechanical Engineers at London in 1972. Twenty-seven versions have now been developed and fully worked out.They are dimensionless and have then three angles as parameters to determine the type of curve with all its properties.The curve types are concerned with those characteristics which the crank-rocker linkage yields for symmetrical coupler curves such as: curves with one or two points of reversal; with internal contact; 8-shaped curves; curves with 2 equal radii of curvature; curves with one or two undulation points on the axis of symmetry; curves with two undulation points oriented symmetrically in relation to each other and a top angle; curves with Burmester points, where the second derivative of the radius of curvature is zero; and curves with one or two tangents which touch the curve at three different points each.The 27 triangular nomograms refer to the symmetrical coupler curves of the 4-bar linkage and are used for selection of the type of curve and corresponding data for the linkage.This article will deal with three of them which relate to coupler curves with the property that a tangent touches the curve at three separate points, while two more examples of the various verions of the nomogram will be presented.A example of the application of the nomogram is given by the design of a transfer mechanism, where use has been made of a curve with two cusps and further modification to a 6-bar linkage.     

Conjugate positions for planar four-bar mechanisms and corresponding special forms of the coupler-curvesKonjugierte stellungen bei ebenen viergelenkgetrieben und die zugenhörigen sonderformen der koppelkurven

Four-bar mechanisms and their variations yield two positions for which the output angle β or the coupler angle γ is identical. These positions are called “conjugate positions” and their significance is discussed. The kinematic inversions of mechanisms in certain conjugate positions leads to new mechanisms with special coupler curves. Coupler points which trace a path with two cusps are easily determined. A similar treatment of the non-turnable double rocker yields coupler curves with three cusps. Requirements for symmetrical coupler curves with two or three cusps can be satisfied.     

Nongrashof机构连杆曲线的几何特征分类法

利用曲线的几何特征 ,对Nongrashof机构的连杆曲线的分类问题进行了研究 ,提出了以曲线的结点、曲线的回转数、变曲点、曲率极大点等为基准的连杆曲线的自动分类法 ,并由此说明了几何特征分类法用于解决复杂曲线自动识别问题的快速有效性     

Real inflections of hinged planar four-bar coupler curves

Plücker's and Klein's equations provide an upper bound on the number of real inflections on the coupler curve of a hinged planar four-bar mechanism. Generally, for any configuration of the four-bar, the coupler points whose trajectories exhibit inflections lie on a circle. The coupler plane is partitioned by the envelope of the inflection circles into connected regions within which every coupler point has the same number of inflections on its trajectory. This enables us to locate coupler curves exhibiting the maximum possible number of inflections.