关键词: 分时复用方法, 绝对位移测量, 纳米时栅, 位移传感器

Abstract: Modern high-end equipment manufacturing requires absolute position measurement, high precision and long ranges for precision displacement detection technology. In view of the conflicts between absolute displacement range and encoding, an absolute nanometer time grating displacement sensor based on time division multiplexing is proposed in this paper. The incremental single-row time grating displacement sensor is employed as the precision measuring part of absolute sensor, which is recorded as sensor A. To achieve the absolute displacement measurement, a convergent incremental time-grating displacement sensor with fewer cycles than sensor A and both numbers of cycles as prime numbers, recorded as sensor B, is added. Absolute displacement measurement is achieved by using the phase value of the traveling wave output from sensors A and B to develop look-up table and perform positioning calculation. A method of time division multiplexing is proposed. Applying excitation signals to the excitation electrodes of sensors A and B in different time effectively reduces the power consumption of the sensors. In addition, the induction electrodes of sensors A and B are connected with leads internally and share a group of induction signal processing interfaces, saving not only a group of induction signal processing devices, but also the circuit space. The sensor prototype is manufactured by multi-layer PCB procedure and the experimental platform is built for testing. Experimental results show the nonlinear measurement error reaches ±3 μm within a range of 450 mm.