Range-Finding Sensor Calibration with Folded Optical Path
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Solution Overview
Problem
The increasing complexity of vehicle sensor systems requires accurate alignment, calibration, and inspection of range-finding sensors, which is challenging due to varying sensor types and manufacturer-specific procedures, often necessitating special arrangements outside typical vehicle service areas.
Innovation Solution
A calibration fixture with a support structure and non-linear signal pathway components that emulate a reflective target at a linear calibration distance, allowing for proper sensor calibration within a compact vehicle service area, using a movable fixture with software guidance for precise placement based on vehicle configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a reflective target is placed at a predetermined calibration distance from the vehicle sensor, then proper calibration of the range-finding sensor is achieved, but the calibration fixture must be positioned outside of a typical vehicle service area
Solution Approach 1:
The patent transforms the calibration problem by changing the spatial dimension. Instead of requiring a long linear distance from the vehicle, the invention uses a non-linear signal pathway that folds the calibration distance into a compact three-dimensional configuration. The signal travels through a complex path involving multiple reflections and refractions within the fixture, effectively packing a long optical path into a small physical space that fits within the vehicle service area.
Solution Approach 2:
The calibration fixture embeds the signal pathway components within each other in a nested configuration. The signal pathway is folded back on itself multiple times, with each segment nested within the spatial envelope of the fixture. This nesting allows the total signal travel distance to exceed the physical dimensions of the fixture, enabling compact calibration within the service area while maintaining the required calibration distance.
2Measurement precision
If calibration procedures are customized for each vehicle and sensor type, then accurate calibration is achieved, but the complexity of calibration procedures increases
Solution Approach 1:
The calibration fixture is designed as a universal device that can calibrate multiple types of range-finding sensors on various vehicle types. The non-linear signal pathway geometry and component arrangements can be adjusted to accommodate different sensor specifications and calibration requirements. This multi-functionality eliminates the need for completely separate calibration procedures for each sensor type, reducing overall system complexity while maintaining accuracy.
Solution Approach 2:
The fixture incorporates adjustable parameters such as the geometry of the signal pathway, the positions of reflective and refractive components, and the spacing between elements. These parameters can be modified to match different sensor types and vehicle configurations. By changing physical parameters rather than redesigning the entire calibration system, the invention maintains accuracy across different applications while simplifying the calibration process.
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 accurate calibration of range-finding sensors within a typical vehicle service area, accommodating various sensor types and vehicle configurations, improving efficiency and reducing the need for specialized setups.
Implementation Method 1
A retro-reflector is disposed within in the signal pathway, such that a non-linear signal travel distance between the entry point and the retro-reflector is of a sufficient length that when the calibration fixture is positioned at a selected location relative to the vehicle, the total distance traveled by a signal emitted from the range-finding sensor which reaches the retro-reflector through the non-linear signal pathway, and is reflected back to the range-finding sensor along the same non-linear signal pathway
Data Source
AI summary
An apparatus and method for aligning, calibrating, or inspecting an onboard vehicle sensor having an external field of view by providing a calibration component on a support structure for positioning at a short calibration distance from the vehicle and which is within the field of view of said sensor. The calibration component is configured to appear to the sensor as if it was positioned at a predetermined linear calibration distance from the vehicle which is greater than the actual short calibration distance.