Encoder output signal correction apparatus and method
AssigneeMitutoyo Corporation
InventorsTetsuro Kiriyama, Ryuichi Koiso, Toshirou Yoshinaka
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Abstract
A third harmonic distortion corrector is equipped for correcting a third harmonic distortion contained in a two-phase sinusoidal signals with different phases output from an encoder. A third harmonic calculator/detector calculates the amplitude a3 and the phase φ3 of the third harmonic using Fourier analysis, based on change in radius r of the Lissajous waveform output from a r-θ converter. The third harmonic distortion corrector corrects the third harmonic distortion of the two-phase sinusoidal signal A4, B4 based on the amplitude a3 and the phase φ3 of the third harmonic calculated.
Claims12
An encoder output signal correction apparatus for correcting two-phase sinusoidal signals with a phase difference output from an encoder, comprising:
- a third harmonic calculator calculating at least one of an amplitude and a phase of third harmonic component contained in said two-phase sinusoidal signals on the basis of a variation in radius of a Lissajous waveform of said two-phase sinusoidal signals, and
- a corrector correcting a third harmonic distortion in said two-phase sinusoidal signals on the basis of at least one of a amplitude and a phase calculated by said third harmonic calculator.
An encoder output signal correction apparatus for correcting two-phase sinusoidal signals with a phase difference output from an encoder, comprising:
- a memory storing at least one of an amplitude and a phase of third harmonic component contained in said two-phase sinusoidal signals,
- a corrector correcting said third harmonic distortion in said two-phase sinusoidal signals, on the basis of at least one of said amplitude and said phase stored in said memory,
- said memory stores at least one of said amplitude and said phase written therein by an outer circuit calculating at least one of said amplitude and said phase, on the basis of a variation in radius of a Lissajous waveform of said two-phase sinusoidal signals.
Dependencies are inferred from the claim text.