PSD Array for Large-Range Displacement Measurement
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Solution Overview
Problem
The limited measurement range of position sensitive detectors (PSDs) restricts the range of a moving platform, necessitating the use of multiple displacement sensors, which complicates signal communication and processing in large-range motion control systems.
Innovation Solution
A PSD array measuring scheme is implemented, where multiple parallel beams of light are generated and detected by a linear array of PSDs and detection headers, allowing for accurate large-range displacement measurement of a moving platform in multiple degrees of freedom, with the optical path distribution device and detection headers providing additional light beams to enhance measurement range and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If multiple displacement sensors are used to extend measurement range, then measurement range is improved, but device complexity increases
Solution Approach 1:
The patent divides the measurement system into multiple PSD detectors arranged in array form, each detecting a portion of the total displacement range. By segmenting the measurement task across multiple detectors with known relative positions, the system achieves extended measurement range while maintaining simple signal processing through straightforward coordinate transformation and data fusion of the segmented measurements.
Solution Approach 2:
The patent combines multiple PSD detectors into a unified measurement system where each detector contributes to the overall displacement measurement. The detectors are merged through a coordinate system that relates their positions, allowing the system to process measurements from multiple sensors simultaneously and calculate comprehensive displacement information without requiring complex individual sensor processing.
2Length of moving object
If multiple displacement sensors are used to extend measurement range, then measurement range is improved, but signal processing complexity increases
Solution Approach 1:
The measurement range is segmented across multiple PSD detectors, each handling a portion of the total range. This segmentation allows the system to maintain simple signal processing for each individual detector while achieving extended overall range through the coordinated arrangement of multiple detectors with predetermined geometric relationships.
Solution Approach 2:
The patent creates a universal measurement framework where multiple PSD detectors perform the same basic measurement function but contribute to different portions of the total displacement range. This multi-functional arrangement allows a single type of sensor (PSD) to serve multiple measurement zones, simplifying signal processing compared to using different types of sensors.
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 solution enables non-contact, high-resolution, and accurate measurement of large-range displacements in industrial motion control systems, simplifying signal processing and reducing complexity, while maintaining high precision and quick response times.
Implementation Method 1
an optical path distribution device is fixed on the moving platform and the optical path distribution device is configured to generate multiple beams of first measuring light parallel to one another
Implementation Method 2
A position sensitive detector (PSD: Position Sensitive Detector) is a PIN-type photodiode sensitive to the position of a light spot from the light incident to a photosensitive surface
Data Source
AI summary
A method for measuring displacement of a large-range moving platform, comprising: arranging multiple beams of first measuring light parallel to one another and generated by an optical path distribution device and a position sensitive detector array in a certain manner, to ensure that at least one beam of first measuring light is detected by the position sensitive detector array when a moving platform is at any position of a moving area; a detection head array capable of determining whether a light beam is shaded being used for auxiliary measurement of a position of the moving platform; and determining a position of the moving platform that corresponds to the first measuring light measured by the position sensitive detector array, to calculate displacement of the moving platform. The method effectively enlarges a measurement range of the position sensitive detector array, and implements measurement of long range displacement of the moving platform.