Synthesis of compliant mechanisms for segment-motion generation tasks

ALEJANDRO ALBANESI; VICTOR D. FACHINOTTI; MARTÍN PUCHETA; ALBERTO CARDONA

Córdoba

Congreso; XVI Congreso sobre Métodos Numéricos y sus Aplicaciones (ENIEF 2007); 2007

Asociación Argentina de Mecánica Computacional

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.