Multiple bifurcated reconfiguration of double-loop metamorphic mechanisms with prismatic joints

The design and analysis of multi-loop metamorphic mechanisms are challenging in the research of metamorphic mechanisms. Inspired by the parallelogram mechanism, this paper proposes a metamorphic mechanism by adding a link to the parallelogram mechanism and changing the properties of some kinematic joints. The metamorphic mechanism has two loops and is composed of six links connected by six revolute joints and one prismatic joint. The topological structure of the metamorphic mechanism is represented by a directed graph, and the multiple bifurcation of the metamorphic mechanism is analyzed by using screw theory and high-order kinematics. The metamorphic mechanism has six bifurcation points and four different motion branches, including one parallelogram branch, one isosceles trapezoid branch and two oscillating block branches. Meanwhile, by combining these metamorphic mechanisms, some novel metamorphic mechanisms with variable sizes and different configurations can be obtained. The metamorphic mechanism proposed in this paper provides a fresh perspective on how to design new metamorphic mechanisms.