Multi‐Objective Optimization for the Cross Brace of a Computer Numerical Control Gantry Machine Tool Based on Intelligent Algorithms

A multi‐objective optimization design method for the cross‐brace structure of a computer numerical control gantry machine tool is proposed to improve mechanical performance. Dynamic and static performance indexes of the cross brace are analyzed. On basis of sensitivity analysis, size parameters which have great influence on mass and dynamic and static performance indexes of the cross brace are selected as design variables for optimization. Objective values under design variables are obtained by orthogonal experimental method, and an objective function is fitted by response surface method. After verifying the fitting effect of the objective function, entropy weight method is used to calculate weight coefficient of each optimization objective, and a comprehensive performance optimization model of the cross brace is built. Accelerated particle swarm optimization (APSO) intelligent algorithm is used to solve the comprehensive performance optimization model. Comparison results before and after the optimization show that the mass of optimized cross brace is reduced by 8.377%, the maximum stress is reduced by 13.252%, and the first‐order natural frequency is increased by 2.183%. The proposed optimization method provides a new idea to improve the dynamic and static performance of the cross brace while reducing its mass.