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由步进电机驱动的虚拟凸轮连杆组合机构,因原动件作步进运动而使连杆点实际轨迹与理论轨迹存在一定的误差,为此将连杆点轨迹进行离散化处理,通过连杆点轨迹的正反解,确定原动件的运动位置及连杆点实际轨迹,并利用最小二乘法原理,通过Matlab编程计算实际轨迹和理论轨迹之间的误差,最终按预定误差要求生成原动件的驱动信息代码,以完成任意连杆点轨迹的理想输出,并举例验证了该方案的可行性。 相似文献
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针对空间RSSR曲柄摇杆机构装配偏差分析问题,首先基于区间分析法和三角模糊数的概念建立了包含间隙和杆长尺寸偏差变动信息的区间模型,构建了偏差回路和非线性区间参数方程组,并对非线性区间参数方程组进行了求解.其次,对空间RSSR机构进行了运动仿真,得出了输出角的名义数据,并与非线性区间参数方程组的求解结果进行对照,绘制出了角位移曲线及不同隶属度情形下的角位移偏差对比曲线.最后,分析了关节处间隙变动和杆长偏差对机构输出角位移偏差的影响.分析结果表明:在机构输出角位移曲线的极小值与极大值点附近,间隙与杆长的变动对输出角位移偏差的影响较显著,且间隙与杆长误差越大,角位移偏差受到影响也越大;调整隶属度数值至合适数值,机构输出角位移偏差有明显改善. 相似文献
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在对PQS-3-D型汽车专用升降机传动系统建模分析的基础上,分析左右对称传动构件的角速度、角加速度、角位移曲线在系统起动时间内有较小差异的主要原因,发现是由于左右传动轴的扭转刚度系数不同造成的,故对传动轴的参数做了修改建议.并分析改进后的输出曲线,在同样的时间段内左右对称传动构件相应的角位移、角速度以及角加速度之间的差异明显减小. 相似文献
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相邻两杆间均不能作相对整周转动的平面四杆机构(Nongrashof机构)的连杆轨迹曲线,广泛应用于非等速运动机构中。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。 相似文献
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A dwell mechanism has been developed based on a coupler curve approximating an involute and utilising a rack and pinion arrangement. The proportions of the basic linkage have been synthesised and the dwell characteristics of the output link have been computed and presented. 相似文献
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Kurt Hain 《Mechanism and Machine Theory》1983,18(2):139-141
Each four-bar linkage running as a crank and rocker mechanism has one unique coupler point producing a coupler curve with two cusps using this special coupler point, complex mechanisms can be designed having exact dwells. In this paper a four-bar linkage is used having the most favorable transmission behavior. Using simple equations, the mechanism and the coupler point location can be calculated. Using a rotating inverted slider output link, the designer can produce two rather long dwells through a full motion period. 相似文献
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The procedure presented in Part I is extended to the case where a 4-bar linkage may by synthesized such that a point on the coupler will trace an approximately circular portion of its coupler curve. The radius and center of this circular coupler curve is prescribed by the definition of a 4-bar linkage in which one of the revolutes will reflect this characteristic. Through the approximation of the behavior of the zeroes of the derivatives of the radius of curvature of the coupler point paths, a family of 4-bar linkages is identified; each member of the family will have approximately the same coupler motion. 相似文献
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连杆曲线轨迹综合的特征图谱 总被引:5,自引:0,他引:5
提出了连杆曲线轨迹综合的特征图谱。该方法通过对连杆平面上所有连杆曲线的类别和尺度特征分析,建立了连杆曲线特征图谱。其方法是,用尖点曲线、自切点曲线及凹凸分界线把连杆平面划分出若干个区域,不同区域内的连杆曲线具有各自的类别特征。而尺寸特征则使用如L、W、J、J1、J2等外形参数来描述,并用绘制等值线的方法建立连杆曲线特征图谱。特征图谱不仅有利于轨迹综合,利用它也可预知任意位置的连杆点的运动轨迹。 相似文献
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H.J. Antuma 《Mechanism and Machine Theory》1978,13(3):251-268
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. 相似文献
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Ming Zhe Chen 《Mechanism and Machine Theory》1983,18(1):63-71
In this paper the author has developed a parameteric equation for the coupler curve of the spatial RRRSR mechanism. Then it is proved by the projective method that the coupler curve and the ruled surface generated by the coupler are of the 32nd order. Finally the imaginary circular point on the coupler curve are discussed. 相似文献
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利用FFT对常用的典型五杆双自由度机构,在其输入均为匀速转动的条件下,建立了其输出特性-输出函数和连杆上轨迹的特征参数图谱,并对其输出特性与五杆机构的尺度、输入角速度、输入转角的初始值之间的关系进行了分析,得到一些规律性的结论,有助于利用五杆机构的输出特性图谱进行五杆机构的尺度综合,并为多杆机构的特性研究提供了帮助. 相似文献