| The spraying robot is an important automatic coating production equipment in modern manufacturing industry,and is widely used in the coating work on the surface of products at home and abroad.The spraying effect of the spraying robot is related to many factors such as the shape characteristics of the workpiece and the spraying process parameters.The key to determining the quality of the spraying effect is the coating trajectory planning.In the trajectory planning of the spraying robot,because the artificial teaching method has the advantages of mature technology and simple programming,it is still the programming mode of most robot trajectory planning at present,but the manual teaching method also has obvious shortcomings,such as programming taking up working time and being difficult planning complex trajectories,the spraying effect depends on the skill level of the workers.Aiming at the many defects of manual teaching method,off-line programming has become a hot topic in domestic and foreign scholars because of its many advantages.This topic studies some key technical problems,including the establishment of spray model,spray path planning and trajectory parameter optimization.The content of the research is mainly composed of the following parts:Firstly,in view of the complex and diverse characteristics of sprayed workpieces in industrial production,the existing spray trajectory planning method is difficult to adapt to the change of workpiece boundary shape.Considering the need of multivariable spray trajectory planning,a spray coating model accurate and fast prediction method that effectively reflects the distribution of coating film thickness is proposed.The method uses spray height,spray width and spray inclination as important controllable parameters of the spray gun to influence the thickness distribution of the coating.The experimental results show that the modeling method of the spray gun mathematical model is feasible and effective,and the established mathematical model of the spray gun is in good agreement with the actual spray pattern.Secondly,in view of the problem of ignoring the curvature of the boundary of the surface when planning the spraying path,it is easy to cause over-spraying and spraying empty stroke,two spatial planning methods for spraying robots are proposed: One is the free-face segmentation modeling and path planning considering the curvature feature.The method is mainly based on the geometric topology principle to shape the free-face patch,and then uses the containment box method to plan the spray path of the sliced surface.Finally,the generated spraying paths are connected according to an optimization algorithm to form a complete trajectory of the spray gun;The other is an offset spray path planning method that considers the boundary factors of the sprayed surface.The method mainly analyzes the influence of the distance from the spraying path to the boundary of the patch on the utilization rate of the coating,optimizes the allowable range of the adjacent path spacing,slices the patch by the plane segmentation method,and obtains the spray path by the offset algorithm.The experimental results show that both methods can achieve good spraying results.Thirdly,aiming at the problem of coating waste and uneven coating thickness when spraying the corner surface with vertical spraying technology,a method of coating trajectory optimization based on variable inclination angle technology is proposed.The method is mainly to establish a variable-angle spray gun model sprayed on the curved surface,and based on the spray path,the spray trajectory optimization model is established with the minimum coating thickness on the surface of the workpiece and the ideal coating thickness difference,and the spray process parameters such as adjacent track pitch,spray rate,spray height,and spray angle are optimized.Finally,the spraying simulation experiment was carried out with the plane and the combined corners as the spraying object,and the spraying results were analyzed and discussed. |
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