Non-contact Deviation Measurement Using Intersecting Laser Lines
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Solution Overview
Problem
Existing mechanical propellant level measurement systems in projectile casings are prone to errors due to their contacting nature, which is inadequate for the precision required with modern propellants, especially when the propellant surface is slanted or yields under the probe's weight, and they fail to provide repeatable, accurate high-sensitivity measurements.
Innovation Solution
A non-contacting deviation measurement system using two laser projectors that project lines intersecting at a nominal location, with an optical sensor capturing the image to calculate the deviation of the propellant surface from the nominal height based on the average distance and angle between the projected lines, allowing for precise measurement without physical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanical probe is used to measure propellant level by contacting the propellant surface, then the measurement system is simple and robust, but the measurement precision deteriorates due to propellant yielding under probe weight and slanted surfaces
Solution Approach 1:
The patent replaces the mechanical probe system with an optical measurement system using laser projectors and cameras. The laser lines are projected onto the propellant surface, and the camera captures the deformation of these lines to calculate surface height without mechanical contact, thereby achieving high precision measurements without the probe weight issue
Solution Approach 2:
The patent introduces laser light as an intermediary between the measurement system and the propellant surface. The laser lines serve as a reference that deforms according to the surface shape, allowing indirect measurement of the propellant level without direct mechanical contact
2Measurement precision
If a single laser line is projected onto the propellant surface, then the device complexity is reduced, but the measurement precision and sensitivity are insufficient
Solution Approach 1:
The patent divides the measurement task into multiple independent laser projectors, each projecting its own line onto the propellant surface. This segmentation allows each projector to independently contribute to the measurement, and their combined data provides higher precision and sensitivity than a single projector could achieve alone
Solution Approach 2:
The patent merges the measurements from multiple laser lines by calculating the average distance between corresponding points on different lines. This combination of multiple measurement sources improves the overall measurement precision and reduces the impact of local surface variations
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 system achieves precise propellant level measurements with high sensitivity, capable of detecting deviations within +/-0.005 inches, significantly improving accuracy over traditional mechanical systems which can vary by +/-0.05 inches or more, and allows for higher resolution depending on the angle between the laser projections.
Implementation Method 1
a first projector projecting a first line and a second projector projecting a second line... An optical sensor is positioned to capture an image of the projections
Data Source
AI summary
A non-contacting deviation measurement system projects a first line and a second line upon a surface of an object. The projections of the first line and second line are arranged to overlap at an intersection line oriented at a nominal location such that when the surface is oriented at the nominal location, the intersection line appears on the surface. As the location of the surface deviates from the nominal location, the first line and second line as projected upon the surface move away from one another. The distance between the lines may be used to calculate the deviation from the nominal location. The deviation calculated may be compared to a predetermined maximum allowable deviation.