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With the development of technology, especially the need of fast accurately running after and
orientating the aim of horizon and air, the photoelectrical rotary encoder with high precision has become the
research hotspot in the fields of international spaceflight and avigation, the errors evaluation of encoder with
high precision is the one of the key technology that must to be resolved. For the encoder with high precision,
the interpolation errors is the main factor which affects its precision. Existing interpolation errors detection
adopts accurate apparatus such as little angle measurement apparatus and optics polyhedron, requesting
under the strict laboratory condition to carry on. The detection method is also time-consuming, hard to tackle
and easy to introduce detect errors. This paper mainly studies the fast evaluation method of interpolation errors
of encoder with high precision which is applied to the working field. Taking the Lissajou's figure produced by
moiré fringe as foundation, the paper sets up the radius vector's mathematical model to represent figure's
form deviation, analyses the implied parameters information of moiré fringe, the relation of the radius vector
deviation and interpolation errors in the figures and puts forward the method of interpolation errors figures
evaluation. Adopting figure deduction method, and directly from harmonic component of radius vector deviation
toward harmonic component of interpolation errors, the interpolation errors can be gotten in the paper. Through
data collecting card, the Moiré fringe signal is transmitted into the computer, then, the computer storages the
data, using figures evaluation method to analyses the data, drawing the curve of interpolation errors.
Comparing with interpolation errors drawing from traditional detect method, the change trend of the
interpolation errors curve is similar, peak-peak value is almost equality. The result of experiment indicates: the
method of the paper can be applied to evaluate interpolation errors of high precision encoder, which need
simple equipment and the examination method is efficient and feasible; Apart from these, the data processing
can be realized by valuation analysis software, and the time is short, the result manifestation is intuitionistic; the
system can be used in the working field, avert the influence of the speed, and has important meaning to the
research of high precision encoder's dynamic precision characteristics.
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