寄生式时栅位移传感器测量原理与结构优化

Measurement principle and structure optimization of parasitic time grating displacement sensor

大型机床在实现全闭环数控过程中,现有测量方法存在回转工作台无法同轴安装角编码器、安装要求高、精度无法保证等方面问题,本文提出一种适用于大型、中空回转工作台角度测量的寄生式时栅位移传感器。传感器通过在两路空间正交的励磁线圈中通入两相时间正交的励磁信号,利用磁导调制方法得到相位差直接反映空间转角的电行波信号,从而实现精密角位移测量。建立由4个传感单元组成的传感器模型,采用电磁场有限元仿真软件建模并仿真,对仿真结果进行误差分析和溯源;根据分析结果对传感器进行结构优化并仿真验证;根据优化模型制作传感器实物,搭建试验台进行实验验证。实验结果表明,在整周范围内传感器测量精度达到±2″,实现了高精度测量,为寄生式时栅的进一步开发应用提供了理论依据。

In the process of realizing the full closed-loop numerical control of large machine tool,the following problems exist.The coaxial angular displacement encoder can ＇t be installed on the rotating table with existing measurement method.Due to the strict installation precision requirement,the installation precision can＇t be guaranteed.In this paper,a parasitic time grating displacement sensor is proposed,which is suitable for the angle measurement of large and hollow rotating table.Two phase time orthogonal exciting signals are applied to the two space orthogonal exciting windings.The magnetic conductance modulation method is used to obtain the electric traveling wave whose phase difference directly reflects the spatial angular displacement.Thus,precision angle displacement measurement is achieved.The angular displacement sensor model with four sensing elements is established,and the electromagnetic field finite element simulation software ANSOFT is adopted to conduct the modelling and simulation of the sensor model.The error analysis and traceability analysis of the simulation result are performed.According to the analysis result,the sensor structure is optimized,and the simulation verification is carried out.A sensor prototype was developed according to the optimized model.A test table was built to conduct experiment verification.The experiment results show that the measurement accuracy of the sensor prototype achieves ± 2″ in the angle range of 0° to 360°,high accuracy angle displacement measurement is achieved,which provides a theoretical foundation for further development and application of parasitic time grating.