Encoder Signal Error Correction for Periodic Position Distortion
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Solution Overview
Problem
Machine operations face inefficiencies due to signal perturbations from imperfectly aligned parts and external fields affecting encoder measurements, leading to imperfect measurements that require effective signal error correction for incremental control signals.
Innovation Solution
A method for signal error correction that determines parameter values for a parameterized approximation of a corrected relative position over time, using measurements of periodic signal errors, and interpolates to estimate a corrected position, providing a more stable frequency output and accurate control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If encoder measurements are used directly without correction, then the device complexity is low, but the measurement precision deteriorates due to periodic signal errors from imperfect alignment and external fields
Solution Approach 1:
The patent applies preliminary action by pre-determining a set of parameter values that characterize the periodic signal error through measurements over at least one period. These parameters are stored and then used to correct subsequent position measurements, eliminating the need for real-time complex error analysis while maintaining high measurement precision
Solution Approach 2:
The patent creates a mathematical model (parameterized approximation) that copies the essential characteristics of the periodic error behavior. This model is then applied to correct measurements, effectively replicating the error correction without needing to physically compensate for each error source
2Measurement precision
If parameter values are determined based on measurements over at least one period of periodic signal error, then the measurement precision improves through error correction, but the loss of time increases due to the correction process
Solution Approach 1:
The parameter determination is performed in advance during a calibration phase, separating the time-consuming measurement process from the time-critical application phase. Once parameters are determined, corrections are applied instantly using simple calculations, minimizing time loss during actual operation
Solution Approach 2:
The patent uses a parameterized approximation with a limited number of parameters rather than attempting to model all error sources in detail. This partial action approach captures the essential periodic error behavior with sufficient accuracy while keeping the correction process computationally efficient and fast
Data Source
AI summary
A method for signal error correction of a position signal relating to a relative position of at least one sensor with respect to a reference, includes determining a set of parameter values of a parameterized approximation of a corrected relative position with respect to time based on measurements of the position signal over a duration of at least one period of a periodic signal error of the position signal. The method further includes estimating a first corrected relative position at a first time based on the parameterized approximation using the determined set of parameter values and the first time.