Absolute Angle Calculation via Signal Correlation Interpolation
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Solution Overview
Problem
Existing absolute angle calculation apparatuses in rotary laser systems face challenges in precise measurement due to long calculation times, which can result in inaccurate angular position determination, especially when measuring multiple targets within a narrow angular range.
Innovation Solution
The apparatus employs a photoelectrically-converted signal storage and correlation detection to interpolate the absolute angular position by detecting the shift amount between previous and current measurements, allowing for faster and more precise calculations through an interpolation calculation circuit and microcomputer processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the calculation circuit calculates the absolute angular position based on spatially modulated components in photoelectrically-converted signal strings, then the measurement precision is improved, but the calculation time increases to about 100 milliseconds
Solution Approach 1:
The patent stores photoelectrically-converted signal strings from previous measurements in advance (preprocessing data), so that when a new measurement is taken, the system can immediately compare current signals with stored historical signals to calculate angular position, significantly reducing calculation time while maintaining precision
2Adaptability or versatility
If the rotary encoder rotates at three revolutions per second (180 rpm) to detect absolute angular position, then the measurement coverage is improved, but the measurement precision deteriorates when targets are within an angular position range of less than 108°
Solution Approach 1:
The patent uses correlation detection to compare current photoelectrically-converted signal strings with previously stored signal strings, detecting shift amounts between them. This feedback mechanism allows precise determination of angular positions even for targets within narrow angular ranges (less than 108°) by referencing historical measurement data and calculating positional shifts
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces calculation time and enhances the precision of absolute angular position measurement, enabling accurate determination even when targets are close together.
Implementation Method 1
a light receiving unit which receives a light beam obtained from the light emitting unit through the patterns and converts the light beam to photoelectrically-converted signal strings
Data Source
AI summary
The absolute angle calculation apparatus includes a calculation circuit calculating an absolute angular position based on a spatially modulated component in a photoelectrically-converted signal string. The calculation circuit includes a photoelectrically-converted signal string storage storing previous and current photoelectrically-converted signal strings obtained, for interpolating the absolute angular position, within a set time shorter than an absolute angle calculation time required to calculate the absolute angular position; a correlation detection circuit detecting a correlation between the previous and current photoelectrically-converted signal strings in the photoelectrically-converted signal string storage and detecting a shift amount therebetween; and an interpolation calculation circuit interpolating an inter-pattern absolute angular position equivalent value based on the shift amount obtained by the current measurement. The calculation circuit calculates an interpolated angle based on the shift amount and the absolute angular position equivalent value, adds the calculated interpolated angle obtained at the current measurement to the absolute angular position obtained at the previous measurement to calculate a current absolute angular position.