关键词: 工件位置偏离, 遗传算法, 优化, 振动, 装夹布局

Abstract: The reasonable planning of the fixturing layout is crucial to guarantee the machining quality and safety manufacturing. Therefore, the prediction and control method is systematically proposed for the workpiece position error. Above all, by transforming the contacts between the workpiece and fixture into the linear spring-damp system, the vibration differential equation of the workpiece, which can determine the position movement of the workpiece in the fixturing layout, is concluded to obtain the workpiece position deviation according to the theory of kinematics and elastic mechanics. Based on the fact that the contacts between the workpiece and fixture are unidirectional, the hook law is used to formulate the constraint conditions of the workpiece position deviation. According to coordinate transformation method, the modal analysis solution technology of the vibration differential equation is proposed to predict the workpiece position error. A numerical test is demonstrated to validate the prediction results are in good agreement with the experimental data in the reference. And then, in order to minimize the workpiece position deviation, the optimal model with the objective of minimizing the 2-norm of the workpiece position deviation is proposed for the fixturing layout. According to the workpiece position deviation in the reasonable fixturing layout, the individual fitness is defined by taking its 2-norm as independent variable. Thus, the genetic algorithm can be skillfully developed to solve the optimal model of fixturing layout. The presented prediction and control method of workpiece position error can avoid the solution of the optimal model under the condition of the workpiece in unstable fixturing. It can provide a basic theory of fixturing layout design for the complex workpiece.

Key words: genetic algorithm, optimization, vibration, workpiece position deviation, fixturing layout