Combination Planning Of Spraying Trajectory For Complex Free-form Surface

Industrial robots gradually replace people and become the main productivity of society in the manufacturing industry.As a typical industrial robot,spraying robots are widely used in production lines of automobiles,aviation and furniture products.Offline spraying trajectory planning is the core technology of spraying robot,and spraying trajectory is the key factor that affects the performance of spraying operation.Complex free-form surface is different from plane and regular surface.It is always a difficult problem to plan spraying trajectory for complex free-form surface because of its irregular geometry and arbitrary curvature.The key technology of spraying trajectory planning for complex free-form surfaces is studied in this paper.According to whether there are holes or not,complex free-form surfaces are divided into free-form surfaces without holes and complex surfaces with holes,which are studied separately.The main work is as follows:The influencing factors of coating deposition in actual spraying are analyzed.Considering the main influencing factors such as spraying speed and path spacing,the film accumulation rate model is established.Considering the accumulation of film thickness under dynamic spraying,the film thickness distribution model under linear path is deduced.On this basis,the optimization model of plane spraying path parameters is builded,and the optimal distance between adjacent paths is calculated by golden divisional method,which provide the foundation for spraying path planning of complex free-form surfaces.Aiming at the free-form surface without holes,a spray trajectory planning scheme is proposed,which divides the task of spray trajectory planning into two subtasks:spray path planning and spray speed optimization.In the part of spraying path planning:Firstly,the direction of point cloud slicing is determined by principal component analysis.Then the initial spraying paths is generated by point cloud slicing algorithm.Finally,the self-intersection of the paths is eliminated based on monotone chain algorithm.In the part of spraying speed optimization,considering the spraying quality and spraying efficiency,a multi-objective optimization model is established to optimize the spraying speed on each path,and the fast non-dominated genetic algorithm is used to solve the model to obtain the spraying trajectory.Aiming at the complex surface with holes,a spray trajectory planning scheme based on surface segmentation is proposed.Firstly,based on the boustrophedon method of plane,a topological segmentation algorithm of 3D surface is designed,which divides the complex surface with holes into a group of patches without holes.Then,the spraying trajectory planning algorithm of free-form surface without holes is used to plan the spraying trajectory of each patch.Finally,the trajectories connection problem is modeled as generalized traveling salesman problem,and a particle swarm optimization algorithm based on double chromosome crossover mutation is proposed to solve it,and the spraying trajectory planning of the whole surface is completed.In this thesis,the design and simulation verification of spray trajectory planning method for complex free-form surface are completed,and the effectiveness and practicability of the proposed algorithm are verified based on typical model by MATLAB programming.