一般空间7R机构位移分析的矩阵法

本文利用文1]的方法,并以旋转矩阵作为主要数学工具,进行一般空间7R机构的位移分析,得出和文2]相同的结果,而推导和计算显著简化。文中利用旋转矩阵的性质3],容易得出各坐标轴单位矢量的方向余弦的递推公式,求出这些单位矢量的标积和混合积,并且可以方便地导出第六个约束方程,推导颇为简捷。此外,文中根据所得16阶行列式的特点,采用先作行变换再按Laplace定理展开的方法进行计算,使计算工作量大为减轻。

A Matrix Method of Displacement Analysis of the General Spatial 7R Mechanism

An input-output equation of the general spatial 7R mechanism is derived in this paper by using the method in 1] and applying the rotation matrices. The result is the same as 2], but the process of derivation is simpler. Applying the character of rotation matrices, it is not difficult to obtain the recurrence formulas of direction cosines of Cartesian unit vectors, to calculate the scalar products and triple products of these unit vectors, and to derive the 6th constraint equation. Moreover, an algorithm, which consists of successive applications of row transformation and expansion based on Laplace's Theorem, is given to evaluate the 16×16 determinant according to its characteristic, so that the evaluation is much simplified.