Design of a topology optimal compliant microgripper using fat Bezier curves

This paper presents the problem formulation and design of compliant microgripper. The microgripper includes a fixed jaw and a movable jaw for engaging opposite surfaces of the article. Actuation of the compliant mechanism drives the movable jaw toward or away from the fixed jaw to close or open the jaws relative to one another. The travel path of the movable jaw is generally at right angles to the gripping surface of the jaw so that the jaws remain parallel to each other as they move toward and away from each other. The automated synthesis of such microgripper is by a structural topology optimization approach. The problem of topology optimization of continuum structures is solved using a multiobjective genetic algorithm coupled with a geometric representation scheme using fat Bezier curve that efficiently defines the variable structural geometry. A graph-theoretic chromosome encoding together with compatible crossover and mutation operators are then applied to form an effective evolutionary optimization procedure. The solution framework is integrated with a non-linear finite element code for large-displacement analyses of the compliant structures, with the resulting optimal designs used to realize various microgripper configurations.