Study On Error Mechanism,Modeling And Compensation For Magnetic Recorder

Supported by "National science and technology major project(No.2015ZX04005001)","National major research instrument development project(No.51527806)","Shanghai industry university research cooperation project(Shanghai CXY-2013-29)",this project takes a 9m straight magnetic recorder made by Shanghai Pingxin electromechanical Manufacturing Co.Ltd.as the object of the study.Based on the analysis of processing mechanism,thermal deformation,positioning error,research of the error measurement,modeling and compensation is discussed and worked out.As one of the most popular position measurement tools,magnetic grid scale is widely used in CNC machine tools and industrial measurement field because of its advantage of low cost,high precision,perfect anti-contamination performance,big distance of run and so on.As the manufacturing machinery of magnetic grid scale,the magnetic recorder's positioning accuracy largely affect the quality and measurement precision of the magnetic grid scale.It is of great practical value and obvious economic function to analyze and study the error mechanism of the magnetic recorder and carry out the error compensation for improving the magnetic recorder's positioning accuracy.The main contents of this thesis include the following aspects:(1)According to the magnetic recorder's bed structure,working principle and magnetic grid scale's recording method,the error formation mechanism of the magnetic recorder and the effects of different error factors are discussed.Then a general synthetic error model is established using the theory of homogeneous coordinate transformation,laying a theoretical foundation for optimization and compensation.(2)Based on the analysis of heat source and heat transfer characteristic,the magnetic recorder's temperature field and deformation field are calculated under the assistance of finite element software.By considering the model prediction results and the actual production situation,thermal key points are discussed,laying the foundation for positioning error measurement and temperature measurement.(3)According to the analysis of the mathematical laws of machine error data up to the thermal equilibrium,the geometric error is established using cubic spline interpolation algorithm and the thermal error is established using the least squares fitting.The mathematical model for geometric and thermal error is tested on a lathe.Then according to the temperature rise characteristic of magnetic recorder,the model is used for its error analysis and forecast.(4)Based on the servo control software,the AC servo motor is ordered to output some distance which is the negative value of the established model's output,then the correctness and validity of the error model is verified,and the positioning error compensation of machine recorder is realized,so as to the improvement of the accuracy of the magnetic recorder and the positioning accuracy of the magnetic grid ruler.