Six novel 6R metamorphic mechanisms induced from three-series-connected Bennett linkages that vary among classical linkages

Abstract Metamorphic mechanisms are capable of changing their mobility by changing the number of effective joints and links under geometrical constraints. In this paper, a new approach in constructing 6R metamorphic mechanisms is proposed and demonstrated by a class of new mechanisms with bifurcated motion. By connecting three Bennett linkages in series and modifying geometrical parameters of the constructed mechanism, six novel metamorphic mechanisms are obtained. Those new mechanisms exhibit bifurcated motion among classical linkages such as the Bennett linkage, the Goldberg 5R linkage, and variant serial Goldberg 6R linkages. Fundamental geometrical constraints are derived with a salient kink angle being defined in the mechanism constructing and modeling. Further, the paper reveals in details the branch transformation and the graph representation of these metamorphic mechanisms.