中国机械工程 ›› 2016, Vol. 27 ›› Issue (02): 187-194,229.

• 机械基础工程 • 上一篇    下一篇

基于单杆矢量的机构复合分离位置函数综合

王成志1;张全明1;王淑可2;周球1;代婷1   

  1. 1.集美大学,厦门,361021
    2.福建省永安市林业局,永安,366000
  • 出版日期:2016-01-25 发布日期:2016-12-15
  • 基金资助:
    福建省自然科学基金资助项目(2012J01225)

Multiply  Separated  Position  Synthesis  of  Function  Generation  Mechanism   Based  on  Monad  Vectors

Wang Chengzhi1;Zhang Quanming1;Wang  Shuke2;Zhou  Qiu1;Dai Ting1   

  1. 1.Jimei  University,Xiamen,Fujian,361021
    2.Forestry  Bureau of Yongan,Yong'an,Fujian,366000
  • Online:2016-01-25 Published:2016-12-15
  • Supported by:

摘要:

提出用单杆相对运动差单元构建平面机构函数综合方程式。首先建立单杆的相对位置运动差及高阶运动差通用单杆矢量公式,再通过引入变量和增加单杆矢量附加方程,消除了方程式中非独立的未知角变量及未知高阶角变量。然后用单杆矢量及其附加方程直接建立有限分离、无限接近分离及复合分离位置函数综合的统一通用的多项式方程组,且方程总次数低。讨论了在平面铰链四杆机构函数综合中的复合五位置问题及复合四位置问题上的应用,用实例计算了“实现函数”与“预期函数”的误差并作出误差波动图,结果表明在无限分离精确点及无限接近分离点上可以精确实现预期函数,但按高阶运动特性要求设计的机构不一定能使“实现函数”在所有0阶位置上更逼近“预期函数”。该方法比双杆组、三杆组法简单,模块性非常好,便于计算机自动建模与求解。

关键词: 相对运动理论;单杆矢量;函数综合, 复合分离位置, 同伦法

Abstract:

The   relative  motion differences of the monads were presented to model the  systems  of  equations  for kinematic function synthesis of planar linkages.The  uniform  formulae  of  the  relative motion  differences with 0-order to higher-order  derivatives  were  constructed firstly,and  then  the  new  variables  and  corresponding  special  auxiliary equations of  the  monad  vectors  were  used to eliminate trigonometric  function,the angular unknowns and  even  their  higher  order angular unknowns.The  monad vectors and their corresponding auxiliary  equations could  be directly used to construct synthesis systems for finitely, infinitesimally and multiply separated precision positions, and the systems were polynomial equations with smaller  values of  the total degrees.Applying  the formulae to   five and four multiply separated positions of function synthesis for pin-jointed four-bar planar  linkages was  discussed.Some  cases  of  the  multiply  separated  positions  were  exemplified  and  their  differences between   the  generated y-value  and  required y-value  were calculated  and  charted.The  results show that the positions at finitely and infinitesimally separated positions  were passed through exactly according  to  the required function.However,the  y-values  generated  by  the mechanism with the higher-order  functional  requirements  may  be no more close to the required y-value  than  those  generated  by the mechanism with the lower-order functional requirements  at all 0-order positions in the required range.The  procedure is simpler and the formulae of monad have the better modularity than the dyad  and triad,and  can  be   easily  adapted  to  automatic modeling and solving the equations  in   a computer.

Key words: relative , motion , theory;monad vector;function generation;multiply separated position;homotopy method

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