Synthesis Of Compliant Mechanisms For Segment-Motion Generation Tasks.

Abstract

In mechanisms design, one of the more common tasks in kinematic synthesis is motion
generation (rigid-body guidance), where a rigid body is moved through a specified motion. If the body to
be guided is flexible and has an initial smooth shape, the task of moving it from its initial configuration
to a specified, also smooth, configuration, is referred to as segment-motion generation. This is the case
for compliant four-bar mechanisms, where the flexible coupler link is the body to be guided, and the
(also flexible) input and follower links are the ones to be synthesized. Previous works on this type of
compliant mechanism neglected the shear stress induced in the links, and the used technique disjoined the
mechanism in order to synthesize a single-link at a time, that would accomplish the specified task. In this
paper we conceive a more realistic approach, considering all flexible links as two dimensional beams with
shear deformation, and synthesized the input and follower links simultaneously, as the flexible guided
body is moved through a sequence of discrete prescribed “precision shapes” in addition to rigid-body
motion, in order to achieve its specified task. The synthesis problem is solved by optimization of the
finite element model, and the method is tested with a numerical example.