Nobuhiko Tsuji

High-performance encoder using the encoder model in a computer

We propose the analysis system and technique for the optical encoder which does not require an analysis of the incoherent light and the diffraction. This system is composed of an LED, a rotation disk, a CCD camera to detect the light intensity for which to transmit a rotation disk, and the photo detector model in the computer, it receives the same output signal as the real encoder. The optical system of the encoder is optimally designed by this analysis system and technique, and then, this high resolution encoder which has the resolution of 100 times and more than the conventional impulse wave encoder is realized.

High-performance absolute optical encoder using M-code

We developed a high-resolution absolute optical encode that achieves a resolution of 4,194,304 Division/Rev at a diameter of 34mm, based on the new angle detection principles, by which the two sets of interpolation data of two differing cycles and M-Code data are mixed. This absolute encoder also achieves an accuracy of 20 seconds to minimize the sinusoid wave distortion of the signal from the photo detector.

Error dispersion algorithms to improve the precision of angle detection for the optical encoder

We have applied the interference fringe scanning algorithms that are used in interference fringe analysis to an optical encoder as angle detection algorithms, in order to disperse the influence of sinusoid wave distortion from the encoders photo detector. We also evaluated these algorithms with the analytical system and techniques for obtaining the same output signal as that of the actual encoder, by using image data on light intensity as the light permeates the slit disk of the encoder. As a result, we obtained about twice the angle precision by applying the algorithms to the optical encoder.