Optical Distance Sensor Pitch Angle Correction
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Solution Overview
Problem
Existing optical position-measuring devices with reflection-measuring graduation are sensitive to tilting movements, particularly pitching tilts, and require effective distance sensors to correct measurement errors, but existing optical distance sensors are not suitable for integration into these systems.
Innovation Solution
An optical distance sensor comprising a first light source, a reflector, two scanning gratings, and a detector arrangement, where the reflected beams pass through the scanning gratings to create a fringe pattern, allowing the evaluation unit to determine distance and correct for pitching tilts by calculating the pitch angle and adjusting position signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical position-measuring devices use reflection-measuring graduation with scanning units, then position measurement along lateral direction is achieved, but sensitivity to pitching movements increases causing measurement errors
Solution Approach 1:
The patent implements a feedback mechanism by continuously measuring the pitching movement using the optical distance sensor and using this information to correct the position measurements. The evaluation unit calculates the pitch angle from the distance sensor signals and applies correction values to the position measurements, thereby compensating for the harmful effect of pitching sensitivity while maintaining high measurement precision.
2Measurement precision
If distance sensors are added to detect pitching movements for correction, then measurement accuracy improves, but device complexity increases
Solution Approach 1:
The patent applies multi-functionality by designing the optical distance sensor to serve dual purposes: it primarily measures the distance to the reflector for pitch angle detection, while simultaneously using the same optical path and detector to enable position measurement along the lateral direction. This integration eliminates the need for separate sensors, reducing device complexity while maintaining improved measurement accuracy through the feedback correction mechanism.
3Measurement precision
If existing optical distance sensors are used for pitch detection, then pitching movement can be detected, but they are not suitable for integration into position measuring devices with reflection measuring graduation
Solution Approach 1:
The patent creates a universal optical measurement system where a single optical distance sensor with reflector can function both as a pitch detection device and as an integrated component of the position measuring device. The sensor uses the same optical path and detector arrangement to measure both the distance to the reflector (for pitch calculation) and the position along the lateral direction, achieving adaptability while maintaining precision.
Solution Approach 2:
The patent introduces the reflector as an intermediary element that enables the optical distance sensor to measure pitch angle by detecting changes in the optical path length. The reflector serves as a mediator between the optical sensor and the mechanical components, allowing indirect measurement of pitching movements through distance changes, thereby enabling compatibility with the reflection measuring graduation system.
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 optical distance sensor enables accurate position determination along two perpendicular directions, effectively detecting and correcting pitching tilts, enhancing the precision of position measurements in optical position-measuring devices.
Implementation Method 1
The bundles of rays emitted by the first light source impinge on the reflector and are reflected back
Implementation Method 2
a periodic fringe pattern with a defined fringe pattern period results in a detection plane of the detector arrangement from the interaction of the beams with the scanning gratings passed through
Data Source
Figure 1
Figure 2~3b
Figure 4a~4b
AI summary
The present invention relates to an optical distance sensor and a position measuring device with such a distance sensor. The distance sensor comprises a first light source, a reflector, two scanning gratings configured as transmission gratings, a detector arrangement, and an evaluation unit. The beams of light emitted by the first light source strike the reflector, undergo back reflection, and then pass through the first and second scanning gratings. In a detection plane of the detector arrangement, the interaction of the beams with the scanning gratings results in a periodic fringe pattern with a defined fringe pattern period. The evaluation unit is designed and configured to determine the distance between the detection plane and the reflector along a first measuring direction, which is oriented perpendicular to the reflector, from the determined fringe pattern period and other known geometric parameters.The distance sensor can be integrated into a position measuring device, which enables position determination along a second measuring direction.