基于平面线圈的高分辨力时栅角位移传感器

针对现有时栅角位移传感器采用漆包线绕制工艺加工线圈,导致线圈布线不均且容易随时间发生变化进而影响测量精度的问题,提出一种基于PCB技术的新型时栅角位移传感器。该传感器通过在PCB基板的不同层上布置特定形状的激励线圈和感应线圈,形成两个完全相同并沿圆周空间正交的传感单元;当在两传感单元的激励线圈中分别通入时间正交的两相激励电流后,通过导磁定子基体和具有特定齿、槽结构的导磁转子对传感单元内的磁场实施精确约束,使两传感单元的感应线圈串联输出初相角随转子转角变化的正弦感应信号;最后通过高频时钟脉冲插补初相角实现精密角位移测量。利用有限元分析软件对传感器进行了建模和仿真。根据仿真模型制作了传感器实物,开展了验证实验,并对实验中角位移测量误差的频次和来源进行了详细分析。经过标定和补偿,最终获得了整周范围内误差在-2.82″~2.02″的时栅角位移传感器。理论推导、仿真分析和实验验证均表明,该传感器不仅能实现精密角位移测量,还能在激励线圈和感应线圈空间极距和信号质量不变的情况下,将位移测量的分辨力从信号源头提高1倍,且结构简单稳定、极易实现,特别适用于环境恶劣的工业现场。

High resolution time grating angular displacement sensor based on planar coils

The measurement accuracy is easily influenced by non-uniformity of coil wiring and variation with time, which is originally because of the use of enameled coils in traditional time grating angular displacement sensor. For this, a new time grating angular displacement sensor based on PCB(Printed Circuit Board) technology was proposed. By arranging particular shapes of excitation and induction coils in different layers of PCB baseboard, the sensor formed two identical sensor units and they were of quadrature positions in the circle; when excitation coils of two sensor units were switched on two-phase time-quadrature AC respectively, magnetic field was precisely restrained by magnetic stator base and magnetic rotor with specific teeth and slots to make induction coils of both sensor units in series output sine sense signal with primary phase varying with rotor's rotation; finally, precise angular displacement measurement was achieved by interpolating high-frequency clock pulse into primary phase. The sensor was modeled and simulated by using FEA(Finite Element Analysis) software. According to simulation models, the sensor object was made and confirmatory experiment was carried out. Frequency and source of angular displacement measuring error were analyzed in detail. Ultimately, the measurement error of the new time-grating angular displacement sensor is within -2.82"~2.02" in the whole scale after calibration and compensation. Theoretical derivation, simulation analysis and experiment verification all indicate that the sensor can not only achieve precise angular displacement measurement, but also it can double the resolving ability of displacement measurement from the signal source when the space pole distance and signal quality of excitation and induction coils are unchanging. The stable structure is easy to be achieved and especially applied to industrial sites in poor environment.