Harmonic Distortion Removal in Positional Change Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing positional detecting devices struggle to uniformly remove harmonic component distortions across various sensors, including optical and magnetic types, leading to inaccuracies in positional change measurements due to differing distortion characteristics.
Innovation Solution
A method involving a control unit that performs Fourier transform on pseudo sine wave signals to identify and remove specific harmonic components, using calculated gains and phase differences to correct positional errors, ensuring accurate detection of positional changes regardless of sensor type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only specific harmonic component distortions are detected and removed, then the distortion removal process becomes simple, but distortions of other harmonic components cannot be uniformly removed across various sensor types
Solution Approach 1:
The patent implements a universal distortion removal method that works across different sensor types (optical, magnetic, etc.) and graduation configurations. The control unit performs Fourier transform on output signals from any sensor type to detect and remove harmonic component distortions uniformly, making the system adaptable to various sensor characteristics without requiring type-specific processing
Solution Approach 2:
The patent changes the processing approach from targeting specific harmonic components to analyzing the frequency spectrum through Fourier transform. This parameter change allows detection and removal of any harmonic component distortion regardless of sensor type, achieving uniform distortion removal across different sensor characteristics by transforming the signal to the frequency domain for comprehensive analysis
2Measurement precision
If graduation intervals are narrowed to increase resolution, then positional change detection precision improves, but manufacturing difficulty increases since graduations cannot be made infinitely fine
Solution Approach 1:
The patent replaces the mechanical approach of creating finer physical graduations with a signal processing approach using Fourier transform. Instead of mechanically carving smaller graduation intervals, the system processes the output signals through spectral analysis to achieve fine positional resolution, substituting mechanical manufacturing complexity with computational processing
Solution Approach 2:
The patent transitions from the spatial dimension of physical graduation intervals to the frequency dimension through Fourier transform. By analyzing signals in the frequency domain, the system can detect positional changes with precision equivalent to very fine graduations without actually manufacturing fine physical markings, effectively moving the resolution achievement from the spatial domain to the frequency domain
3Measurement precision
If Fourier transform is performed on output signals to detect and remove harmonic component distortions, then measurement precision improves, but calculation complexity in the control unit increases
Solution Approach 1:
The patent extracts only the necessary frequency components through Fourier transform - specifically identifying and removing harmonic component distortions while preserving the fundamental signal. This selective extraction approach achieves high measurement precision by focusing computational resources on removing only the harmful harmonic components rather than processing the entire signal spectrum equally
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
The present invention provides a method for detecting a positional change amount due to a movement of a moving body by reading, with a sensor, a plurality of gradations disposed along the direction of the movement. The method includes: a step for taking, as one period, one gradation among the plurality of gradations and acquiring a pseudo sinusoidal signal in response to the positional change amount; a step for executing a Fourier transform on the pseudo sinusoidal signal within the range of at least one gradation, and calculating, from the spectral intensity of each frequency component obtained by the Fourier transform, the signal intensity of a fundamental wave component and the signal intensity of at least one harmonic component; a step for calculating a gain corresponding to each of the at least one harmonic component by dividing each signal intensity of the at least one harmonic component by the signal intensity of the fundamental wave component; and a step for detecting the positional change amount by subtracting, from the pseudo sinusoidal signal, each harmonic component multiplied by a corresponding gain.