Research On Trajectory Planning For Robot Spraying Based On Surface Model

In the context of the transition from traditional manufacturing to intelligent manufacturing,industrial robots,as an important carrier of intelligent manufacturing,will play an important role in improving the degree of industrial automation,leading the high-tech development,and accelerating the transformation of production.As a branch of robot application field,robot spraying has been widely used in various industries,greatly improving the production efficiency and product quality of spraying industry.It is of a great of practical significance to study spraying trajectory planning of large complex surfaces of work piece.Based on the Global Castings(Tianjin)wind power generator castings robot automatic painting project,this paper focuses on the trajectory planning method for spray painting of complex casting surfaces.Aiming at the characteristics of large and complex casting surfaces and spraying process requirements,a sub-region offline planning and design scheme was formulated.According to the design scheme,the hardware platform construction and software system composition are discussed in detail,and the overall spraying implementation process is also provided.We introduced the data format of the work piece model surfaces,selected STL as the data source for model processing,and studied the storage and extraction methods of STL model information.Besides,we used the surface processing function of CAD software and the robot motion space to segment the surfaces of work piece.Furthermore,we studied the method of generating small curvature patches based on the normal vector segmentation,which provides a data foundation for the generation of spraying paths on the facets.The key to spraying trajectory planning is the generation of spraying paths which based on facets.After analyzing the shape of each facet,the choice of path pattern,the adjacent distance between paths,and the path processing method at the junction of adjacent facets,an algorithm for generating a basic path based on the STL model slicing technique is proposed.After that,the generated basic path points are processed for redundant point filtering.The situation of redundant points is analyzed in detail.The algorithm of spatial distance threshold judgment and continuous scanning is used,which realizing the optimization of the basic path points.Then the orientation coordinate system is constructed for the optimized path points,and the calculation formula of the orientation angle is given.After this,the planning of the spraying path points of the facets is completed.Import the obtained facet patch spraying path points sequence into the Kawasaki robot offline programming system and simulate it in the offline system,which proves that the program algorithm generates the correct path.The spray trajectory and motion program were further generated by the offline system,and the simulation analysis was completed.The offline spraying results were used to guide the actual spraying operation.Finally,the effectiveness of the offline trajectory planning was verified based on the actual spraying effects.