Research On Grinding Trajectory Planning Of Robot For Complex Parts Based On Virtual Debugging

Aeroengine blades are the key precision parts of aircraft engines,and their surface integrity and profile accuracy have a vital impact on the aerodynamic performance,service life,reliability and other aspects of the engine.The blade is a typical thin-walled part,which has the characteristics of easy deformation and large bending and torsion.The severe surface curvature change makes it difficult to ensure the surface quality of the blade during the grinding process.Therefore,the research on the high-efficiency and high-precision automatic grinding technology of the blade can improve the production efficiency of the blade.And the manufacturing level is of great significance.At present,robotic blade grinding has gradually replaced manual grinding as the mainstream grinding technology.In the process of robotic grinding the blade,a good grinding trajectory can effectively improve the surface quality and processing efficiency of the blade.The use of virtual commissioning technology can simulate the actual industrial robotic grinding blade according to the technical parameter requirements designed by the user,thereby effectively reducing the risk of physical grinding.This paper focuses on the research of blade model reconstruction,trajectory planning and joint virtual commissioning of the robotic grinding blade system.Through the combination of software and hardware,the system’s control situation is tested and verified,and the mechanical design,process simulation,trajectory planning and electrical commissioning are integrated.The commissioning efficiency is improved,and problems can be found and solved before the equipment is installed,which reduces the risk and cost of physical commissioning.The main research contents of this paper are as follows:(1)Point cloud processing and model reconstruction of navigation blades.Firstly,Hualang 3D scanner was used to collect point cloud data of solid blades.Then,noise points were removed from the initial blade point cloud data,and the blade point cloud data was simplified based on K-means algorithm.Secondly,the blade surface was reconstructed based on NURBS surface,and the errors of the reconstructed blade surface were analyzed.The results showed that the maximum,average and standard deviations of the reconstructed blade point cloud surface were all within 0.05 mm,which met the accuracy requirements.Finally,the three-dimensional model of the propeller blade is reconstructed in NX.(2)A method of blade oriented robotic grinding trajectory generation was studied.Visual Studio 2017 as the development platform,combined with NX secondary development tool NX/ Open API to achieve the development of grinding trajectory based on equal residual height.Firstly,through the analysis of the differential geometry of the blade surface,the mathematical model between the grinding tool and the blade surface was established.Then,the Douglas-Peucker algorithm was used to calculate the variable grinding step size.The blade surface was divided into three conditions: plane,convex and concave,and the corresponding grinding row spacing was calculated respectively.Finally,the grinding track and track point data that conform to the surface topography of the blade were automatically generated on the surface of the three-dimensional blade model,and the simulation was carried out to verify whether the grinding track generated was feasible.(3)The kinematics model of robotic grinding blade was established.Firstly,the kinematics model of Kawasaki RS20 N joint robot was established by D-H parameter method,and the solution process of forward and inverse kinematics of Kawasaki robot was deduced.Then,the trajectory planning of the robot in joint space and Cartesian space is studied theoretically,and the trajectory motion simulation is carried out,which verifies the correctness of the kinematics model of the robot and ensures the feasibility of the theory.Finally,the robot workspace was solved based on the Monte Carlo method,and the point cloud map of the robot workspace was drawn.(4)A virtual commissioning system for robotic blade grinding based on NX MCD and TIA Portal is designed.Firstly,a digital workstation for robotic blade grinding was designed and established based on NX MCD simulation platform.Then use TIA Portal software to design PLC program and HMI configuration and download to the hardware device;Secondly,OPC UA communication protocol was used to realize the joint virtual commissioning of the robotic blade grinding system.Finally,the process parameters suitable for actual blade polishing are given,and the actual blade polishing experiment proves that the parameters are reasonable and feasible.The commissioning results show that the system can effectively verify and optimize the robotic grinding trajectory,shorten the field commissioning period,and reduce the commissioning risk and cost of electrical hardware in the design stage.