Starting off from the theory of spherical triangle, an analysis was carried out on the relation between component twist angle of spherical four-bar linkage and circuit of mechanism.
从球面三角理论出发，对球面四杆机构构件扭角和机构回路的关系进行分析；
2
The relationships between the points in space model and the dimensional classification of spherical four-bar linkage are also established.