Angle Detecting Device Self-Calibration Sensor Head Segmentation
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Solution Overview
Problem
Conventional angle detecting devices, such as rotary encoders, face challenges in obtaining highly accurate calibration values without losing frequency components of higher powers, which requires increasing the number of sensor heads, thereby increasing costs.
Innovation Solution
An angle detecting device with a self-calibration function that uses a combination of first and second sensor groups with equiangular intervals, where the second group's calibration values are phase-shifted and averaged to compensate for missing frequency components, allowing for accurate calibration up to the least common denominator of the sensor head counts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of sensor heads is increased to obtain highly accurate calibration values without losing frequency components of higher powers, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent divides the sensor heads into two distinct groups: a first group with L sensor heads arranged at equiangular intervals, and a second group with M sensor heads arranged at equiangular intervals. This segmentation allows each group to capture specific frequency components, and by combining their calibration values, the system achieves high measurement precision without requiring a single large group of N sensor heads, thus reducing device complexity while maintaining calibration accuracy.
2Measurement precision
If the number of sensor heads is increased to capture frequency components up to higher powers, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent segments the sensor heads into two groups with different counts (L and M) that are relatively prime. This segmentation enables the system to capture frequency components up to the least common multiple of L and M by combining calibration data from both groups, achieving high-frequency detection capability without manufacturing the expensive single-group configuration with N = lcm(L, M) sensor heads.
Solution Approach 2:
The patent introduces a new dimension of calibration data processing by performing phase shifting and addition operations on calibration values from the two groups. This dimensional transformation in the data processing domain allows the system to synthesize high-frequency calibration information that would otherwise require a much larger number of physical sensor heads, thereby reducing manufacturing cost while maintaining measurement precision.
Data Source
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AI summary
{Problems} To obtain highly accurate calibration values, without losing frequency components up to higher powers, while the number of sensor heads is kept at the minimum number. An angle detecting device with a self-calibration function has sensor heads for reading a scale at a circumference of a scale disc fixed to a rotating shaft, which device has first sensor heads arranged with an equiangular interval at the circumference of the same scale disc and a second sensor head arranged at a position of one of the first sensor heads in place of the one of the first sensor heads, and performs self-calibration by obtaining measurement differences between the second sensor head and the first sensor heads to determine average values thereof, in which the first sensor heads and the second sensor head are calibrated with a first group including L sensor heads arranged with an equiangular interval and a second group including M sensor heads arranged with an equiangular interval, and in which phases of the calibration values obtained from the second group, are shifted by a scale of j*P/L(j=1 to L-1), where the total number of scale marks arranged on the scale disc is denoted as P, and average values of the calibration values obtained from the second group and the shifted calibration values are obtained, the average values are added to the calibration values obtained from the first group, and the added values are output as calibration values.