Research On The Thermal Deformation Of The Magnetic Recorder

Compared with the grating scale which has high precision but requires stricter working condition, the magnescale is more favorable due to its higher reliability, lower cost, stronger interference immunity, oil and water resistance, etc.. Therefore, it is a better choice as a linear or rotational displacement transducer in industrial use. The precision of magnescales depends on the pitch error of N-S stripes recorded onto the scale. As a high-precision device, the magnescale is subject to the irregular nonlinear heat deformation of the guide rail suffering from the unhomogeneous temperature distribution. Thus it is of great significance to analyze the effects of individual heat sources on the temperature field of magnetic recorder and the heat deformation of guide rails, based on which, proper error compensation strategy should be put forward in order to improve the recording precision.This paper takes a 3m long magnetic recorder as the research subject.Firstly the recording principle, heat deformation, error model, the status quo and the development trend of error compensation techniques arediscussed. Then a 3D finite element analysis(FEA) model under multiple heat sources is established to help analyze the temperature field of recorder and the heat deformation of guide rails. Meantime, the influence pattern of these heat sources is also explored. Specifically, the main research contents are as following.First, a calculation model for temperature field of magnetic recorder was built in the Fluent — — a fluid analysis software. The simulation results in Fluent were compared with the on-site measurement results for the recorder, thus verifying the reliability of the model. Then the controlled variable method was implemented to analyze the impacts on the temperature field of recorder from all possible influential factors.In order to study the thermal deformation of guide rails, the calculated temperature field by Fluent was imported into FEA to obtain the heat deformation along the guide rail. Likewise, the controlled variable method was applied again to analyze the effects of each influential factor on the thermal deformation of rails as well as on the residual error after linear compensation.Then, polynomial fitting and multiple linear regression were applied to model the residual error of guide rails after linear compensation and to verify the reliability.At last in the end of this paper, the main work was summarized and further research goals were proposed.