Aplicação do algoritmo genético na síntese cinemática e na otimização do mecanismo de quatro barras

Abstract

Linkages can be used in various types of machines and equipments. In order to estimate the appropriate dimensions of linkages that are capable of describing a prescribed motion, dimensional synthesis must be employed. The task where a point control is required is known as curve or trajectory generation. The objective of this work is the implementation of a methodology applicable in the dimensional synthesis and optimization of planar four-bar linkages, for curve generation. As a basic simplifying assumption, the links are considered as rigid members, or underfomable bodies. This assumption is considered reasonable for most dimensional synthesis problems. The proposed procedure uses precision points as reference, which must be used to describe the desired curve. The search is done using the genetic algorithm based on differential evolution, which allows working with the variables in the form of real numbers. It is a heuristic methodology that uses three basic operations: selection, reproduction and mutation. In order to validate the algorithm, comparative analyses are performed using results from similar works. In order to verify the application of the algorithm in engineering problems, the objective function is modified for the optimization of a four-bar linkage, present in an industrial sewing machine. The point of interest of the obtained mechanism has a 39,9% reduction of the horizontal "jerk" peak, without changing the vertical movement. The computational procedure implemented to perform the dimensional synthesis and optimization of four-bar linkages can render good results for the kinematic preliminary design of planar mechanisms.