Research On Modeling And Compensation Technology Of Machining Error Based On Online Measurement Data Of The Equator

Quality is the core requirement in the process of workpiece manufacturing.Machining error compensation is an efficient way to improve processing quality.The method of error compensation based on the measurement data of part is an important branch of the error compensation methods.At present,the research of error compensation based on part’s measurement data mainly uses the coordinate measuring machine to obtain the part’s surface data,however the error data cannot be obtained quickly;and the existing research is mainly based on reverse engineering and CAM software to regenerate the compensated part model and processing code,which make it difficult to apply in the workshop.For batch processing scenarios,this thesis proposes a system of machining error modeling and compensation based on the feedback of the measurement data of the Equator to realize fast and convenient machining error compensation in the workshop environment.The main contents are as follows:(1)Designed a machining error measurement and compensation system.Based on the characteristics and advantages of the Equator,an error modeling and compensation system is proposed for parts online measurement requirements,which including data preprocessing,deterministic error modeling,and i-code generation functions.(2)Designed deterministic error model modeling scheme.Considering the characteristics of the model’s continuity and the repeatability and locality of systematic errors,this thesis proposes a deterministic error model based on B-spline approximation and spatial autocorrelation analysis and an error model based on local polynomial regression respectively.Among them,the former uses B-spline approximation technology to establish a model,and uses spatial autocorrelation analysis to check the completeness of the model establishment,and finally forms an iterative scheme for establishing the deterministic error model;the latter uses the coordinate distribution in the local neighborhood of each point to estimate the coordinate of each point under the influence of the system error,forming a segmented solution to establish a deterministic error model.(3)Designed the generation scheme for compensation information.Based on the KD tree to find the nearest instruction point of the error model point,establish the instruction domain mapping relationship of the error model,and then the system error value is extracted and corrected;and the system error compensation information is generated based on the mirror symmetry method;the i-code with the error compensation information is finally output.(4)Developed system software and conducted experimental verification.Using Python,a modeling and compensation system for machining error based on the measurement data of the Equator was developed.Through the measurement and compensation of butterfly parts,the accuracy of contour processing was improved,and the effectiveness of the model and algorithm was verified.