Three Novel Symmetric Waldron-Bricard Reconfigurable Mechanisms And Their Extended Reconfigurable Mechanisms

Compared with traditional mechanisms whih single motion characteristics,reconfigurable mechanism involves the design philosophy of fulfilling multiple tasks in different configurations using one mechanism or integrated system.This dissertation explores the possibilities to design reconfigurable mechanisms using the symmetry-properties.Then the bifurcation property of these designed reconfigurable mechanisms is thoroughly investigated.By integrating Bricard’s line and plane symmetries based on Waldron’s Bennett-mechanism integration approach and using the Wohlhart’s isomerization method,three novel symmetric Waldron-Bricard reconfigurable mechanisms as well as their extended isomeric 6R linkages are proposed in this dissertation.The dissertation also proposes an extended 6R reconfigurable mechanism and a kinematotropic 8R mechanism.The novel line-symmetric Waldron-Bricard linkage with one Waldron motion branch,two general and three special line-symmetric Bricard motion branches is obtained by integrating two identical general Bennett loops.The novel plane-symmetric Waldron-Bricard reconfigurable linkage is obtained by coalescing two equilateral Bennett loops and possess two plane-symmetric motion branches.The novel line-plane-symmetric hybrid Waldron-Bricard reconfigurable linkage is obtained by blending two identical equilateral Bennett loops,with several motion branches including Waldron and plane-symmetric Bricard motion branch,the line-plane-symmetric Bricard motion branch,the spherical 4R motion branch and three special line-symmetric Bricard motion branches.Each of the three novel Waldron-Bricard linkages then results in an extended isomeric 6R reconfigurable linkage.By changing DH parameters of plane-symmetric Waldron-Bricard mechanism,a reconfigurable plane-symmetric Bricard-Spherical linkage is obtained,with a plane-symmetric Bricard motion branch and a spherical 4R motion branch.Based on the proposed approach and way of construction,a kinematotropic 8R mechanism is obtained,with two plane-symmetric 8R motion branches and an asymmetric 8R motion branch.Further,through properly designing the parameters,the kaleidocycle motion of this linkage are revealed and the foldability is verified in virtue of the alternative form of Bennett linkage.The findings not only offer an intuitive approach to design reconfigurable linkages,but also bridge three linkages,i.e.,the Waldron’s hybrid linkage,the line-symmetric and the plane-symmetric Bricard linkage,which plays an important role in exploring the intrinsic relationship between the Bennett-based linkages and Bricard linkages.