Confocal Sensor Device for Cylindrical Cavity Surface Inspection
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Solution Overview
Problem
Existing sensor devices struggle to precisely measure non-smooth surfaces of cylindrical cavities, such as those with inclined or hook-shaped projections, due to limitations in measurement direction and range, which affects the accuracy of surface inspection and coating application.
Innovation Solution
A sensor device with at least two sensor units, each with elongated shape and external optics allowing measurement directions to form specific angles relative to the longitudinal axis, enabling precise optical confocal distance measurements by moving the units into the cavity and adjusting angles for first and second distance measurements, allowing effective measurement of non-smooth surfaces without tilting or rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single sensor unit with fixed measurement direction is used, then the device complexity is reduced, but the measurement precision of non-smooth surfaces deteriorates
Solution Approach 1:
The sensor device is divided into multiple sensor units (at least two), each with different measurement directions. This segmentation allows each sensor unit to capture surface features from its specific angle, collectively providing comprehensive and precise measurement data for non-smooth surfaces without requiring complex rotation mechanisms in a single sensor.
Solution Approach 2:
Each sensor unit is assigned a specific measurement direction optimized for capturing particular surface features. The first sensor unit measures at an angle of 20° to 85° relative to the direction of movement, while the second sensor unit measures at an angle of 95° to 160°, allowing each sensor to specialize in detecting specific types of surface irregularities based on its local measurement perspective.
2Device complexity
If the measurement direction is perpendicular to the longitudinal axis, then the sensor unit structure is simplified, but the ability to measure inclined projections deteriorates
Solution Approach 1:
The measurement direction of each sensor unit is specifically oriented to match the characteristics of the surface features being measured. By setting the first sensor unit's measurement direction at 20° to 85° and the second at 95° to 160° relative to the direction of movement, the system optimizes each sensor's local measurement capability for detecting inclined projections and hook-shaped features without requiring complex sensor rotation.
3Measurement precision
If confocal sensors are used within their limited range, then measurement precision is improved, but the ability to measure varied surface angles deteriorates
Solution Approach 1:
The system uses multiple confocal sensor units, each maintaining its high measurement precision within its specific measurement range. By segmenting the measurement task across multiple sensors with different angular orientations, the system achieves both precise measurements and adaptability to various surface angles without requiring any single sensor to operate outside its optimal range.
Solution Approach 2:
The solution adds angular dimensionality by deploying sensor units at different measurement angles rather than relying on a single sensor rotating or tilting. This dimensional approach allows the system to maintain the precise confocal measurement capability while adapting to varied surface angles through the collective coverage of multiple fixed-angle 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
Enables precise measurement of non-smooth surfaces, including inclined projections and depressions, within the limited range of confocal sensors, ensuring accurate geometric data collection and improved coating application on cylindrical cavities.
Implementation Method 1
at least two sensor units which are set up for an optical confocal distance measurement. The at least two sensor units have an elongated shape and have external optics through which a measurement direction, in which light can be emitted and received
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
A sensor device for surface inspection of a cylindrical cavity, comprising at least one sensor unit configured for optical confocal distance measurement. The at least one sensor unit has an elongated shape and features external optics through which a measurement direction, in which light can be emitted and received, is perpendicular to a longitudinal axis of this sensor unit. The sensor device also includes a movement mechanism configured to extend and retract the at least one sensor unit in a specific direction within the cylindrical cavity under inspection.Control means are provided for measuring surface elevations of the cylindrical cavity and are configured to actuate at least one sensor unit for a first distance measurement, in which the measuring direction is at an angle of 20° to 85° relative to the direction of movement, and at least one sensor unit for a second distance measurement, in which the measuring direction is at an angle of 95° to 160° relative to the direction of movement. For this purpose, the measuring direction of the at least one sensor unit can be at an angle between 95° and 175° to the longitudinal axis of this sensor unit, which is held by a rotatable bearing so that the same sensor unit can be moved to different rotational positions for the first and second distance measurements.Alternatively, the at least one sensor unit can comprise at least a first and a second sensor unit, wherein the first sensor unit is designed and connected to the motion device such that its measuring direction is at an angle of 20° to 85° relative to the direction of motion, and wherein the second sensor unit is designed and connected to the motion device such that its measuring direction is at an angle of 95° to 160° relative to the direction of motion. A corresponding method is also disclosed.