Trajectory Planning And Optimization For Small-curvature Freeform Surface Spraying Based On Genetic Algorithm

As an important branch of industrial robots,spraying robots are widely used in the fields of automobile,watercraft and aviation.Because the application of spraying robots is useful to improve the spraying quality and spraying efficiency,spraying robots have gradually phased out manual spraying,and become an essential part of modern products manufacturing process.The surface features of modern high-end industrial products,such as automobile hoods,aircraft surfaces and cabinet surfaces,are more and more complicated.Most of them are small-curvature freeform surfaces.But there are still some deficiencies about trajectory planning and optimization for small-curvature freeform surface spraying.The existing methods cannot achieve the desired spraying results.At the same time,domestic scholars put little emphasis on the development of trajectory planning and optimization software system for small-curvature freeform surface spraying.Most of the commonly used software systems are developed by foreign enterprises such as DURR,SIEMENS and ABB.Therefore,this paper carries out the research on trajectory planning and optimization for small-curvature freeform surface spraying.The research is mainly from the trajectory planning and optimization of spraying gun,the trajectory planning and optimization of spraying robot joints,the trajectory planning simulation system for spraying robots and the spraying experiment on the automobile hood.The main research contents of this paper are as follows:Firstly,a spraying model of high-speed electrostatic rotary cup has been built.Based on it,a coating thickness distribution model on freeform surface after spraying was established.Based on genetic algorithm and the coating thickness distribution model,the trajectory of spraying gun during the spraying process has been planned and optimized.Secondly,according to the design requirements of spraying robot,combined with the design method of general industrial robots,the 3D model of spraying robot has been established.According to the trajectory of spraying gun which has been planned and optimized,based on genetic algorithm and newton iteration method,the trajectory of spraying robot joints during the spraying process has been planned and optimized.Thirdly,the trajectory planning simulation system for spraying robots has been developed based on MATLAB/GUI.The simulation system is composed of four sections,such as the generation of point cloud,the generation of spraying gun model,the calculation of forward kinematics and the trajectory planning of spraying robot joints.Finally,as a typical small-curvature freeform surface,the automobile hood was selected for the spraying experiment.The point cloud data of the automobile hood was collected from 3D model.Then,based on the coating thickness distribution model and the trajectory planning and optimization method proposed by this paper,the spray experiment has been carried out.The experimental results have proved that the method proposed by this paper is feasible and effective.