Design And Characteristic Analysis Of Shape-changing Rigid-body Mechanisms

Shape-changing rigid-body mechanism is a kind of mechanisms that can change its shape through the movement.Its implementation capacity is strong,enough to adapt to different work requirements,in line with today's mechanical systems to multi-purpose development trend.Its design objective is approximating a shape change defined by a set of curves,called as design profiles,through the synthesis of rigid-body kinematic chains.Firstly,different types of design profiles are analyzed.Because design profile is a complete curve,so it apparently can't meet the design accuracy requirement.Design profiles need to be transformed into actual profiles of mechanism,called as mean profiles.Then the transformation method is introduced.In order to reduce the design complexity of shape-changing rigid-body mechanism with significant differences in arc length,this paper puts forward a new design process.Software is also designed to simplify the transformation process of shape-changing rigid-body mechanism's profiles.Secondly,the structure synthesis method of shape-changing rigid-body mechanism is presented.Then starting from the simple linkage motion synthesis,through comparing the advantages and disadvantages between graphic method and analytic method,motion synthesis method of shape-changing rigid-body mechanism synthesis is given.At the same time,in order to select good performance mechanism,analysis of the characteristics of shape-changing rigid-body mechanism is given.So the design of the whole mechanism is completed.Finally,in order to verify the design method,corresponding design examples are given,which laid the foundation for the practical application of shape-changing rigid-body mechanism.Meanwhile,in order to expand the application range of shape-changing rigid-body mechanism,shape changes of spatial graphs are realized by multiplying planar mechanisms with prismatic joints.