Single grate type time-grating displacement sensor based onphotosensitive array direct modulation

Because conventional Moiré fringe gratings are difficult to be manufactured and assembled, this paper proposes a single grate type time-grating displacement sensor based on a time subdivision space. Based on the particle characteristics of light, a generation method of light field electronic traveling wave by light field signal with orthogonal transform was analyzed. Then, by using dot matrix Light Emitting Diode(LED) modules as alternating light sources, the electronic traveling wave signals to response the displacement values were obtained by coupling the space orthogonal photosensitive array with the receiving device. Finally, the space linear displacement was measured by detecting the time difference of zero-crossing between electronic traveling wave signal and excitation signal. A principle prototype was developed and validated experimentally by using a common mechanical processing method. The testing results demonstrate that measuring errors of the developed prototype are controlled within ±2 μm after error correction in a measuring range of 440 mm. The single grate type time-grating displacement sensor relaxes the requirements for installation process and improves its anti-interference ability. Moreover, the measurement technique avoids the weaknesses of traditional coarse grating technologies such as difficult to improve measuring accuracy and poor dynamic characteristics and provides a new method not to be depend on mechanical subdivision for improving the precision of optical displacement measurement. © 2016, Science Press. All right reserved.