Wheel Caster Angle Measurement via Sidewall Image Comparison
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Solution Overview
Problem
Current methods for determining the caster angle of a vehicle wheel require complex steering angle routines, making it time-consuming and inconvenient to detect changes in the caster value during adjustment work.
Innovation Solution
A method and device that utilize image recording and analysis to determine the roll-off angle of the wheel by capturing and comparing images before and after adjustment, employing optical flow analysis and transforming images into polar coordinates to simplify the measurement of the caster angle change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a steering angle routine is used to determine caster angle changes, then measurement precision is maintained, but productivity decreases and loss of time increases
Solution Approach 1:
The patent replaces the mechanical steering angle routine with an optical measurement system. An imaging device captures images of the wheel sidewall, and image processing algorithms automatically determine the roll-off angle and calculate caster angle changes, eliminating the need for manual steering operations while maintaining measurement precision.
Solution Approach 2:
The patent creates an optical copy (image) of the wheel sidewall and processes this copy to extract measurement information. By analyzing the image data rather than performing physical steering operations, the system achieves rapid caster angle determination without sacrificing measurement accuracy.
2Measurement precision
If a steering angle routine is used to determine caster angle changes, then measurement precision is maintained, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical steering operations with a simplified optical imaging system. The measurement process involves capturing images with an imaging device and processing them computationally, which reduces mechanical complexity while maintaining or improving measurement precision through automated image analysis.
3Productivity
If optical flow analysis is applied to determine wheel rotation, then productivity increases and loss of time decreases, but device complexity increases
Solution Approach 1:
The patent uses optical flow analysis and image processing algorithms to automatically determine wheel rotation from captured images. This computational approach replaces manual measurement methods, significantly improving productivity and reducing measurement time, while the complexity is managed through software-based solutions.
Data Source
Figure 1~2
Figure 3~4b
AI summary
The invention relates to a method for determining a roll angle (β) of a wheel (2), in particular a wheel (2) of a vehicle, about an axis (D), having the following steps: - capturing a first image which comprises at least one region of a lateral wall of the wheel (2); - extracting a first representation of the lateral wall of the wheel (2) from the captured first image; - rotating the wheel (2) about the wheel axis (D); - capturing a second image which comprises at least one region of the lateral wall of the wheel (2); - extracting a second representation of the lateral wall of the wheel (2) from the captured second image; and - comparing the first representation with the second representation in order to determine the roll angle (β) of the wheel (2). A change of the wheel caster angle (α) can be determined from the thus determined wheel (2) roll angle (β) in a simple and reliable manner.