基于构造特征时变磁场的单码道绝对式时栅位移测量方法研究

The current domestic absolute displacement sensors have some shortcomings such as low measurement accuracy and resolution, slow response and poor stability, which have a gap with imported high-end products and seriously restrict the further development of measurement and control system in China. Time grating displacement sensor measures the spatial displacement by the amount of time, due to its anti-oil and anti-dust ability of the strong features, making it particularly suitable for complex or harsh working environment. In order to solve the problem of low measurement accuracy caused by the mutual coupling of the magnetic fields of absolute and incremental code track when using the time grating displacement sensor to measure the absolute displacement, a new measurement method of single-coding track absolute displacement based on the time-varying magnetic field with structural features is proposed. Using spatio-temporal transformation theory, a fluctuating magnetic field with a specific time-varying behavior is generated by constructing a spatio-temporal orthogonal excitation; according to the precise constraint mechanism, special space-time markings of the time-varying magnetic fields are realized by precisely confining the magnetically permeable medium; using multi-field coupling theory and coupling model, high-accuracy absolute displacement measurement can be achieved by effective coding and specific decoding of spatio-temporal markings. The innovations are as follows: (1) A new special single-track coding and time-stamping model for spatial location is established, to achieve the effective extraction of absolute position; (2) a high-efficiency displacement solution rule for a specific space-time marking model is proposed, to achieve high-precision absolute displacement measurement.

现有国产绝对式位移传感器存在测量精度和分辨力低、响应速度慢、稳定性差等缺点，与进口高端产品存在差距，严重制约着我国测量和控制系统的进一步发展。时栅位移传感器利用时间量测量空间位移，抗油污和粉尘能力极强的特点使其特别适合于复杂或恶劣的工作环境。针对现有时栅位移传感器进行绝对位移测量时绝对码道和增量码道磁场互相耦合导致测量精度低的问题，提出一种基于构造特征时变磁场的单码道绝对位移测量方法。利用时空变换理论，通过构造时空正交激励，产生具有特定时变行为的波动磁场；根据精确约束机理，通过导磁介质精确约束，实现对时变磁场的特殊时空标记；利用多场耦合理论和耦合模型，通过对时空标记的有效编码和特定解码，实现高精度的绝对位移测量。创新之处在于：(1)建立一种新的对空间位置的特殊单码道编码和时间标记模型，实现对绝对位置的有效提取；(2)提出一种针对特定时空标记模型的高效位移解算规则，实现高精度的绝对位移测量。

现有国产绝对式位移传感器存在测量精度和分辨力低、响应速度慢、稳定性差等缺点，与进口高端产品存在差距，严重制约着我国测量和控制系统的进一步发展。时栅位移传感器利用时间量测量空间位移，抗油污和粉尘能力极强的特点使其特别适合于复杂或恶劣的工作环境。针对现有时栅位移传感器进行绝对位移测量时绝对码道和增量码道磁场互相耦合导致测量精度低的问题，提出一种基于构造特征时变磁场的单码道绝对位移测量方法。通过时空正交的激励产生具有特定时变行为的波动磁场，再通过导磁介质对时变波动磁场进行精确约束，实现磁场三维形态的精确调控，构造出具有特定时空标记信息的空间特征磁场，最后根据时栅的时空变换理论对空间特征磁场进行精确的时空编码和时空解码。根据所建立的传感器数学模型和物理模型，分别用MATLAB和ANSYS软件进行了数值仿真和瞬态电磁场有限元仿真。仿真结果表明，在动子导磁体齿槽边缘存在漏磁及激励磁场分布不均的问题。针对上述问题，提出采用优化后的分体式转子结构，以增强转子导磁体齿部对磁场的约束并加快磁场在槽部的衰减。优化后的分体式转子模型其两路绝对感应信号和增量感应信号间的相位差经滤波后具有与理论推导一致的规律性，满足对极判断需求，且各路感应信号幅值均能得到有效提高。根据仿真优化后的传感器模型研制了传感器样机，搭建了样机实验平台，开展实验研究。实验结果表明，采用18对极、偏置角为0.5°的绝对式传感器结构，整周测量原始精度为±185.77″。对传感器误差进行了分析和朔源，在此基础上采用逐点补偿法对测量结果进行修正后，样机3次测量平均精度为±13.43″，可在整周范围内实现绝对位移测量，且易于制造及对环境不敏感，可为高分辨力绝对位移测量提供一种低成本下的新解决方案。