Distance Measuring Device Jitter Suppression via Mirror Positioning
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Solution Overview
Problem
In three-dimensional measurement methods using pattern light projection, jitter in the frequency information of the current signal from the light detection unit reduces measurement accuracy due to decreased projection reproducibility of the pattern light.
Innovation Solution
A distance measuring device with a light detection unit placed at a position equal to or less than 90% of the maximum swing amplitude of the mirror, receiving the reflected laser beam and outputting a light reception signal to control the generation of pattern light, thereby suppressing jitter and enhancing reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the light detection unit detects a part of the pattern light for controlling the time to project the pattern light, then the projection reproducibility of the pattern light may be increased, but the frequency information contained in the current signal contains jitter causing reduction in measurement accuracy
Solution Approach 1:
A phase-locked loop circuit is introduced as an intermediary between the light detection unit and the control unit. This circuit processes the current signal from the light detection unit, extracting timing information while filtering out jitter. The phase-locked loop circuit generates a timing signal that is synchronized with the mirror's swing, ensuring accurate pattern light projection timing without the harmful jitter present in the raw detection signal.
Solution Approach 2:
The system implements feedback by continuously monitoring the light reflected from the mirror using the light detection unit. The detected signal is fed back to the phase-locked loop circuit, which adjusts the timing control signals accordingly. This closed-loop feedback mechanism ensures that the pattern light projection timing remains synchronized with the mirror's actual swing position, compensating for any jitter or deviations.
2Reliability
If the light detection unit is placed at a position equal to or less than 90% of maximum swing amplitude of the mirror, then jitter is suppressed and projection reproducibility is enhanced, but the detection range and responsiveness may be reduced
Solution Approach 1:
The system changes the operational parameters of the light detection unit by adjusting its placement position relative to the mirror's swing amplitude. By positioning the detection unit at 90% or less of the maximum swing amplitude, the system optimizes the detection timing to occur when the mirror is at a specific phase of its swing cycle. This parameter adjustment ensures that the detection unit captures light signals at optimal moments, reducing jitter while maintaining sufficient detection range and responsiveness through the phase-locked loop circuit's timing compensation.
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
The solution increases the reproducibility of the pattern light and improves the accuracy of distance measurements, leading to enhanced performance in object recognition and robotic operations.
Implementation Method 1
a light output unit outputting a linear laser beam
Implementation Method 2
a light scanning unit including a mirror that reflects the laser beam from the light output unit while swinging and generating a pattern light on an object
Implementation Method 3
receiving the light reflected by the mirror and outputting a light reception signal
Implementation Method 4
an imaging unit imaging the pattern light, a measuring unit measuring a distance to the object based on a result of imaging by the imaging unit
Data Source
AI summary
A distance measuring device includes a light output unit outputting a linear laser beam, a light scanning unit including a mirror that reflects the laser beam from the light output unit while swinging and generating a pattern light on an object, a light detection unit placed in a position equal to or less than 90% of maximum swing amplitude of the mirror, and receiving the light reflected by the mirror and outputting a light reception signal, an imaging unit imaging the pattern light, a measuring unit measuring a distance to the object based on a result of imaging by the imaging unit, and a control unit controlling generation of the pattern light based on the light reception signal.