Tilt Detection Using Rotating Line Laser and Time-of-Flight
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Solution Overview
Problem
Conventional tilt detecting systems for photodetection devices suffer from low accuracy and speed, and are unable to miniaturize while maintaining measurement range, especially when detecting tilts relative to horizontal and vertical lines.
Innovation Solution
A tilt detecting system comprising a surveying instrument with a horizontally rotatable line laser projecting unit, polyhedron sensors, and an arithmetic unit that detects tilting angles based on photodetection time deviations, allowing for high-accuracy and high-speed detection without increasing detector size, using a diffraction grating for enhanced sensitivity and omnidirectional tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the interval between two detectors is increased to improve detection accuracy, then measurement precision is improved, but the size of detectors must be increased in proportion to maintain measurement range
Solution Approach 1:
The patent replaces the conventional mechanical/optical system using two separate detectors measuring deviation lengths with a single photodetection device using time-of-flight measurement. The line laser projects vertically, and the photodetection device measures the time difference for light to reach different photodetection units, eliminating the need for large detector intervals and sizes while achieving high measurement precision.
Solution Approach 2:
The patent changes the measurement parameter from spatial deviation (distance between photodetection positions) to temporal deviation (time difference of light arrival). This parameter transformation allows accurate tilt detection without requiring large physical detector intervals, thus reducing detector size while maintaining or improving measurement precision.
2Measurement precision
If conventional tilt detection methods are used, then tilt angles can be detected, but accuracy and responding speed are low
Solution Approach 1:
The patent replaces conventional tilt detection mechanisms with a time-of-flight laser measurement system. The line laser projects vertically along the pole, and the photodetection device measures the time difference for light to reach different photodetection units. This optical-time measurement system provides both high accuracy and fast response speed, overcoming the limitations of conventional mechanical or slow optical detection methods.
Solution Approach 2:
The line laser is rotated to periodically scan the target, and the photodetection device captures time-of-flight data at different angular positions. This periodic scanning allows the system to accumulate multiple measurements and calculate tilt angles with high accuracy and fast response, as the rotation provides rapid successive measurements.
3Volume of moving object
If conventional tilt detection devices are used, then tilt angles can be measured, but miniaturization cannot be achieved while maintaining measurement range
Solution Approach 1:
The patent replaces conventional tilt detection devices with a compact time-of-flight measurement system. A single photodetection device with multiple photodetection units arranged vertically measures tilt by detecting time differences of light arrival. This system achieves miniaturization because it eliminates the need for large detector intervals, while maintaining measurement range through the vertical arrangement of photodetection units and the rotating line laser that scans the target.
4Adaptability or versatility
If the size of detectors is increased to maintain measurement range, then measurement range is preserved, but device complexity and size increase
Solution Approach 1:
The patent replaces complex multi-detector configurations with a simplified single photodetection device containing multiple small photodetection units arranged vertically. The line laser projects vertically, and the time difference for light to reach different photodetection units provides tilt information. This substitution simplifies the overall device structure while maintaining measurement range through the vertical unit arrangement and laser rotation.
Solution Approach 2:
The single photodetection device with multiple photodetection units serves multiple functions: it detects tilt angles in different directions, measures distance via time-of-flight, and maintains measurement range without requiring large detector sizes. The rotating line laser also provides both illumination and measurement functions, reducing overall device complexity.
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
Enables easier, more accurate, and faster detection of tilting angles, reducing the need for large detectors and improving working efficiency by canceling response time differences and averaging detection signals, while allowing for miniaturization and three-dimensional position correction.
Implementation Method 1
a target with a retro-reflectivity
Implementation Method 2
the tilt detecting system further comprises a diffraction grating provided on the line laser projecting unit, wherein the line laser is divided at a predetermined angular interval
Data Source
AI summary
The invention provides a tilt detecting system comprising, a surveying instrument having a distance measuring function and a line laser projecting unit installed as horizontally rotatable for projecting a vertical line laser, and a photodetection device having at least two photodetection units provided at a known interval, a target with a retro-reflectivity and an arithmetic unit, wherein the line laser projecting unit is rotated, each of the photodetection units are made to scan the line laser and the arithmetic unit detects a tilting angle of the photodetection device based on a deviation between a photodetection time moment of each photodetection unit and the distance measurement result of the target of the surveying instrument.