摘要
将Burmester理论从平面及球面拓展到一般空间领域,给出了空间RCCC机构的一种综合方法。一般情况下,综合RCCC机构最多能给定连杆的3个位置。而4C机构的四位置综合可以得到无穷多解,因此可先建立4C机构无穷多解的解域,再在解域中找到主动杆与机架间C副无滑动位移的点作为R副,从而得到RC连架杆,最终获得RCCC机构。具体方法为:首先根据给定的4个位置的姿态角求解出满足要求的解曲线,并根据解曲线建立球面4R机构解域。其次在球面4R机构解域上选取一点作为RCCC机构运动副轴线方向的矢量,再与给定的4个位置的空间坐标结合求解出满足要求的解直线,进而根据解直线建立空间4C机构的解域。最后在空间4C机构的解域图中找到通过4个位置时主动杆与机架间C副无滑动位移的点作为R副,构成满足要求的空间RCCC机构。本文最后通过给出的数值示例证明了该方法的正确性和有效性。
The generalization of spherical rectification theory was considered to spatial RCCC linkages to visit four given positions. The problem of synthesis of spatial four-bar linkages of the RCCC type for rigidbody guidance with four given positions was focused,in which R denoting a revolute,C denoting a cylindrical kinematic pair. While synthesis equations for CC and RC dyads were available in literatures,the synthesis of spatial RCCC four-bar linkages required special attention due to its asymmetric topology.However,infinitely many exact solutions to the problem of CC-dyad synthesis existed for the four-pose rigid-body-guidance problem,the RC-dyad synthesis admitted only approximate solutions,thus the RCCC linkage was capable of visiting four positions. A solution region theory was proposed to synthesis a RCCC linkage which was to visit four positions. Firstly,the expression of spherical Burmester curve and the classification was given to make a solution region. The second solution region（ moment solution region）was born follow-up by picking a point on Burmenster curve solution region. Secondly,the second region which also was the spatial 4C linkage solution region,while the linkage was 2-DOF. Through restricting the prismatic joint between drive and ground on spatial 4C linkage solution region,a spatial RCCC linkage which can visit four given positions was got. Finally,two examples were given which proved that the theory was validated and correct.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2016年第8期399-405,共7页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家自然科学基金项目(51275034)
关键词
空间RCCC机构
四位置综合
解域方法
spatial RCCC linkage
four positions synthesis
solution region method
