小型化高精度绝对式时栅角位移传感器

Absolute time-grating angular displacement sensor with the feature of high-precision and miniaturization

针对机器人关节臂、关节臂式测量机等设备中所用绝对式角位移传感器面临的高精度和小体积之间的矛盾，研制了一种基于电场式时栅传感技术的绝对式、高精度、小型化角位移传感器。采用内圈单对极粗测结合外圈多对极精测的方式，实现绝对定位功能；采用单排差动传感结构能有效抑制共模干扰的优点，保证测量精度；采用传感电极和电路元件的集成化设计，实现了小型化。使用PCB工艺制作了外径为φ=45mm的传感器样机，通过实验分析表明，内外两圈之间的交叉串扰导致了对极内的一次谐波误差。在此基础上提出增大两圈间隙和布置中间屏蔽地的优化方案，使最终测量精度达到了±5．5″。该传感器在具备低功耗、低成本、小体积等特点的同时，拥有巨大的产品化潜力。

The absolute angular displacement sensor is widely applied in the articulated robotic arm, articulated arm measuring machines, and other equipment. To balance the contradiction between the high precision and small volume, an absolute angular displacement sensor based on electric field type time-grating sensing technology is developed in this study. The sensor utilizes the inner ring rough absolute-position measurement component combined with the outer fine incremental-displacement measurement component to obtain absolute positioning measurement. To ensure the measurement accuracy, the single row differential sensing structure of the time- grating sensor is adopted to eliminate the common mode interference. To achieve miniaturization, the integration of the sensor electrode and circuit elements is used. The sensor prototype is manufactured using PCB technology with φ 45 mm outer diameter. The experiments show that the cross interference between the two circles results in the first-order error. On this basis, the optimization scheme of increasing the gap between two circles clearance and the shielding ground at intermediate position layout shield ground is put forward. Experimental results show that the developed angle displacement sensor can achieve the ± 5.5＂ measurement accuracy. The sensor has the characteristics of low cost, low power consumption, small size, and owe the great potential for production.