Encoder interpolator with enhanced precision
AssigneeActive Precision, Inc.
InventorBradley Hunter
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Abstract
A method is presented for converting the sine/cosine signals from an optical encoder into a high-resolution position signal for use by a position control system while eliminating common noise and error sources. The improved noise performance resulting from the alias-free demodulation of encoder signals improves precision and reduces power consumption in precision motion control applications. The adaptive compensation of harmonic distortion eliminates errors related to offset, gain and quadrature of the encoder channels. The interpolator is able to process encoder signals at extremely high resolution without the speed limitation of prior art encoder interpolators.
Claims20
An encoder interpolator, comprising:
- a state estimator that demodulates and interpolates received encoder signals, wherein a sample rate of the state estimator is faster than a highest frequency of an encoder being processed, and wherein the state estimator determines an estimated position being monitored by the encoder being processed and compares the estimated position with an encoded position that is encoded in the received encoder signals, the difference thereof being an estimated error, and wherein the state estimator outputs the estimated position and the estimated error;
- and
- a circuit that receives from the state estimator the estimated position and the estimated error and determines update information that is used to modify the encoder signals that are received by the state estimator.
A method of providing encoder interpolation, comprising:
- demodulating and interpolating received encoder signals, wherein a sample rate of the demodulating and interpolating is faster than a highest frequency of an encoder being processed;
- determining an estimated position being monitored by the encoder being processed;
- comparing the estimated position with an encoded position that is encoded in the received encoder signals, the difference thereof being an estimated error;
- outputting the estimated position and the estimated error;
- determining update information using the estimated position and the estimated error;
- and
- using the update information to modify the received encoder signals prior to the demodulating and interpolating.
A computer readable storage medium storing computer software that provides encoder interpolation, the computer software comprising:
- executable code that demodulates and interpolates received encoder signals, wherein a sample rate of the demodulating and interpolating is faster than a highest frequency of an encoder being processed;
- and
- executable code that determines an estimated position being monitored by the encoder being processed;
- executable code that compares the estimated position with an encoded position that is encoded in the received encoder signals, the difference thereof being an estimated error;
- executable code that outputs the estimated position and the estimated error;
- and
- executable code that determines update information using the estimated position and the estimated error;
- and
- executable code that uses the update information to modify the received encoder signals prior to the demodulating and interpolating.
Dependencies are inferred from the claim text.