变耦型时栅传感器及测头姿态对测量误差的影响

根据时栅传感器的测量原理,提出一种采用高频时钟脉冲作为测量基准的变耦型时栅位移传感器以提高位移测量的精度。该传感器通过改变激励线圈和感应线圈的耦合状态输出感应位移变化的行波信号来实现精密位移测量。进行了建模和仿真,研究了不同测头姿态下传感器的位移误差特性,并对其进行了谐波分析,得到了不同测头姿态对位移测量误差各次谐波的影响规律。根据传感器模型制作了传感器并开展了验证实验。仿真和实验结果均表明:不同测头姿态对位移测量误差的影响主要体现在对测量误差的1次、2次和4次谐波上,且俯仰姿态引入的附加误差最大,其余测头姿态下引入的位移测量附加误差均较小。若保证较佳的测头姿态,传感器在定尺和动测头间气隙厚度为0.3mm时的原始误差约为±18μm。实验分析结果与仿真结果基本一致。

Variable coupling time grating sensor and effects of sensor-head attitudes on measuring errors

On the basis of the measuring principle of time grating sensors, a new variable coupling time grating displacement sensor was proposed by employing a high-frequency pulse as measurement basis to improve the precision of displacement measurement. The precision displacement measurement of the sensor was implemented by changing the coupling state of excitation and induction coils to output a traveling wave signal for inducing the displacement change. By modeling and simulations, the displacement error characteristics of the sensor when sensor-head was in different attitudes were obtained. The harmonics analysis was performed, and the influence of different sensor-head attitudes on different resonances of the displacement measurement errors was obtained. A sensor prototype was designed based on the model and then experiments were carried out. Simulations and actual experiments indicate that different sensor-head attitudes mainly influence 1st, 2nd and 4th harmonics, and other harmonics are more sensitive to pitch attitudes than other attitudes of the sensor-head. When the sensor-head is in a good attitude and the gap between ruler and sensor-head is 0.3 mm, both experimental analysis and simulation result show that the measurement error is about ±18 μm. Simulations and actual verification experiments are in agreement well.