基于二次时间基准的时栅角位移传感器误差在线自修正方法研究

The traditional error correction methods of time grating displacement sensors are performed by higher precision measurement instruments served as measurement standard. However, these traditional error correction methods aren't sutiable to some harsh measurement environments, and the correction precision is restricted by the precision of calibrating instruments. Therefore, according to the multiple-poles, multiple-probes and error characteristics of time grating sensors, this project presented an online self-calibration method of time grating based on the second time measurement standard. This method adopted time as measurement standard for error correction, and spatial errors are sampled every equal time interval during certain spatial value. Using time-space corresponding and transformation theory, spatial orthogonal errors which are hard to correct directly are transformed into time orthogonal errors with error tracing technology. In this way, time orthogonal errors can be corrected by adjusting electronic parameters. The first time measurement standard and the second time measurement standard are united into time quantity. Therefore, time grating displacement sensors don't depend on higher precision instruments to realize an online self-calibration. As a result, the correction precision doesn't rely on the precision of calibrating instruments, and the applications of time grating sensors are further broadened out.

针对时栅角位移传感器以高精度母仪作为基准的传统误差修正方式不适合某些极端应用环境而且修正精度受限于基准母仪的问题,本项申请拟以时栅角位移传感器为研究对象，利用时栅角位移传感器特有的多对极、多测头结构以及误差特性，提出一种基于二次时间基准的时栅角位移传感器误差在线自修正方法。该方法利用精度高而且容易构造的时间量作为传感器误差修正基准，对传感器一个间距内的误差进行等时间误差采样，实现传感器的误差测量。利用时空对偶与时空转换思想，通过误差溯源，将不容易直接修正的空间正交误差项等效转换为容易修正的时间正交误差项，然后统一采用调整电气时间参数的方法从时间量上对误差进行修正。该方案将时栅角位移传感器的一次时间测量基准和二次时间修正基准都统一到时间量，去除了传感器误差修正对高精度基准母仪的依赖，实现时栅角位移传感器的误差在线自修正，突破修正精度受限于基准母仪的瓶颈，进一步拓展时栅角位移传感器的应用范围。

时栅位移传感器是一种采用“以时间参量间接测量空间参量”思想研制的新型精密角位移传感器，具有测量精度高、抗干扰能力强、价格低廉等优点，具有极大的推广应用价值。为了解决时栅位移传感器在误差修正环节对外部精密基准仪器的依赖，结合时栅位移传感器的误差特性，提出了基于时间基准的时栅位移传感器误差在线自修正方法。 研究了时栅角位移传感器对极点与对极内分度误差的规律，建立了时栅传感器误差分析的数学模型，得出了时栅位移传感器由于独特的多测头结构，传感器的误差在整周范围内以对极为周期等间距圆周分布，对极点误差小于0.2″，可为时栅位移传感器的误差修正提供了理论基础；根据时栅位移传感器的误差特性，建立了基于时间基准的时栅位移传感器误差在线自修正模型，构建了传感器的对极内误差的等时间采样模型，以谐波叠加算法对传感器的对极内误差曲线进行了拟合，以对极误差曲线对传感器整周的误差曲线进行重构；建立了时栅位移传感器空间正交信号与时间正交信号测量误差之间的数学关系模型，分析出传感器对极内误差主要是二次误差成分，通过误差溯源理论，将测量误差中不容易直接修正的空间正交误差项等效转换为容易修正的时间正交误差项，采用调整电气时间参量的方法从时间参量上对传感器测量误差进行在线修正。研制了基于时间基准的时栅位移传感器误差在线自修正样机，传感器样机的直径为Φ120mm,对极数为90，采用的激励信号频率为400Hz，经过误差修正之后，传感器样机的整周测量误差为±0.9″，分辨力为0.036″ 。基于时间基准的误差自修正方法可以使时栅位移传感器在误差修正环节摆脱外部高精度基准仪器的限制，推动时栅位移传感器在国防军工、超大尺寸极端制造等领域的应用。