平面二维时栅位移传感器的理论模型与误差分析

Theoretical model and error analysis of the planar two-dimensional time-grating displacement sensor

本文提出了一种平面二维位移测量方法,并研制出了一种新型的平面二维时栅位移传感器。首先,建立了平面二维时栅测量模型,采用一种离散化的电极编码阵列,实现了二维平面上的编码;其次,提出了一种测量信号解耦方法,通过对4块正交排列的动尺电极上的感应信号进行线性运算,实现了对输出行波信号的解耦;建立了三维电场仿真模型并进行仿真分析,仿真结果验证了离散化电极编码的可行性和解耦运算方法的有效性;此外,通过仿真得到了平面二维时栅位移传感器的误差特性,其主要以4次误差为主,并且随着间隙的增大而衰减;最后,采用PCB工艺制造了传感器样机进行实验。实验表明:在300 mm×300 mm范围内,二维时栅传感器在X方向大量程误差为±8μm,Y方向大量程误差为±8.4μm,实现了可靠的二维位移测量。

Proposes a planar two-dimensional displacement measurement method and develops a new type of planar two-dimensional time-grating displacement sensor. Firstly, a planar two-dimensional time-grating measurement model is established and a discrete electrode encoding array is used to achieve the encoding on the two-dimensional plane. Secondly, a decoupling method of measurement signals is proposed. Through linearly calculating the induced signals on the four orthogonally arranged moving ruler electrodes, the decoupling of the output traveling wave signal is realized, a three-dimensional electric field simulation model is established and the simulation analysis is carried out. The simulation results verify the feasibility of the discretized electrode encoding and decoupling calculation methods. In addition, the error characteristics of the planar two-dimensional time-grating displacement sensor are obtained through simulation, the error is mainly based on the fourth-order error and attenuates with the increase of the gap. Finally, a sensor prototype was manufactured using PCB technology and experiment was conducted. Experiments show that within the range of 300 mm×300 mm, the two-dimensional time-grating sensor has a large range error of ±8 μm in the X direction and a large range error of ±8.4 μm in the Y direction, and reliable two-dimensional displacement measurement is realized.