Research On Path Planning Of Laser Cladding Manipulator For Large Complex Parts

Remanufacturing,as a typical form of green manufacturing,is an advanced form of resource recycling and an important measure for developing a circular economy,building a resource-saving and an environment-friendly society.In the continuous exploration,China has proposed the remanufacturing mode of “surface restoration and performance improvement method”,which makes up for the shortcomings of the foreign remanufacturing industry model with “replacement method and dimensional repair method” as the core.As an important means of remanufacturing,laser cladding robot can realize the rapid remanufacturing of parts,but there are still some problems to be applied to large complex parts.In this paper,the problem of laser cladding manipulator path planning for large complex parts is taken as the research object,and the research objective is to realize automatic planning of laser cladding path for large complex parts.The key technologies in path planning are studied.The main contents are as follows:(1)The mathematical tools used in kinematics analysis are introduced.The kinematics model of the manipulator is constructed by using D-H linkage coordinate system.The forward and inverse kinematics equations of the manipulator are derived.The optimal method of the inverse kinematics solution is given,and the workspace of the manipulator is analyzed.In order to make full use of the maximum speed of the manipulator,the trajectory planning function of quintic polynomial transition is derived.The correctness of theoretical deduction is verified by using the simulation platform constructed by Matlab/SimMechanics.(2)In order to improve the efficiency of collision detection,a skeleton-based bounding volume hierarchy tree establishment method is proposed,and the collision detection algorithm is studied.The skeleton of the model is extracted based on the mesh contraction,and the skeleton is optimized to construct the linear skeleton tree of the model.In order to make the bounding volume more closely surround the object,the concept of oriented ellipsoid bounding box is proposed,and its calculation and optimization methods are given.The numerical method is used to solve the intersection test problem between bounding boxes.The construction of bounding volume hierarchical tree based on the guidance of skeleton tree can simplify the construction process and retain the structural characteristics of the model.The collision detection tree between objects is established,and the collision detection is transformed into the search of collision nodes in the collision detection tree,and the frontline tracking technology is used to improve the search efficiency.(3)In order to obtain the optimal path of collision-free manipulator considering the processing order,genetic algorithm is introduced into the path planning of manipulator.Based on the analysis of the characteristics of laser cladding tasks,the IPS mathematical model for obstacle avoidance and the ETSP mathematical model for determining the processing order are proposed.Multi-population genetic algorithm and multi-layer coding genetic algorithm are used to solve IPS and ETSP problems respectively.The efficiency of the proposed algorithm and the performance of dealing with complex scenes are verified by experiments.(4)Aiming at the interference between nozzle and parts in cladding process,the method of eliminating interference by adjusting sprinkler attitude is discussed.The influence of the inclination angle of the nozzle relative to the surface of part on the quality of the cladding layer is analyzed,and the maximum angle of nozzle tilt is determined.The concepts of interference-free feasible region of SCP and adjacent configuration are proposed,and the trajectory space of SCP is constructed.Based on the optimal trajectory,an algorithm for searching the non-interference trajectory in the trajectory space by interference checking is proposed.The feasibility of the proposed method is verified by case study.