ON THE BRANCH FORMATION OF LINKAGES

摘要

A spatial linkage with the displacement governed by two fundamental equations can be regarded as a virtual double loop system. The mobility of the linkage is affected by the mobility of each individual "loop" as well as the interaction between the loops. The current use of branch points for branch identification is limited to linkages with simple topology, such as Stephenson-type linkages, which are simplified versions of group 2 mechanisms. However, in a general spatial group 2 linkage, both the fundamental equations are equivalent to virtual five-bar loops. Branch points in Stephenson-type linkages should be generalized to explain and define the interaction between two virtual five-bar loops. The concept of generalized branch points offers the explanation of how branches are formed in spatial group 2 linkages. This paper presents the theoretical background for the mobility analysis of complex spatial linkages.