Wheel-Mounted Sensor Axial Misalignment Compensation
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Solution Overview
Problem
Existing wheel alignment systems face inefficiencies and errors due to the need for extensive wheel rotation and vehicle jacking to compensate for axial misalignment between wheel-mounted sensors and the wheel axis of rotation, particularly in hybrid systems that lack efficient methods for generating a surface of revolution for machine-vision compensation.
Innovation Solution
A method that compensates for axial misalignment by measuring sinusoidal variations in toe and camber angles during a limited wheel rotational movement of 60 degrees or less, allowing simultaneous compensation of all vehicle wheels without jacking, using rotation matrices and encoder readings to determine the axis of rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional mechanical compensation methods are used to compensate for sensor axial misalignment, then measurement precision is improved, but loss of time increases due to extensive wheel rotation and vehicle jacking requirements
Solution Approach 1:
The patent applies partial action by performing compensation measurements at only two specific wheel rotational positions (0 degrees and 180 degrees) rather than requiring full 360-degree rotations or multiple positions. This partial sampling is sufficient to calculate the axial misalignment offset through averaging, dramatically reducing the time required while maintaining adequate measurement precision
Solution Approach 2:
The patent replaces the mechanical compensation process (manual adjusting screws, bubble levels, and physical wheel rotations) with an electronic/computational system. The offset is calculated automatically by the alignment system using sensor readings from two positions, eliminating the need for mechanical adjustments and extensive manual operations
2Measurement precision
If wheel rotation of 180 degrees or more is performed for compensation, then measurement precision is improved, but device complexity increases due to vehicle jacking requirements
Solution Approach 1:
The patent requires only 180 degrees of wheel rotation (or even less in some implementations) rather than full 360-degree rotations or multiple rotation cycles. This reduced rotational range eliminates the need for complex vehicle jacking systems and multiple support points, simplifying the overall device while maintaining sufficient precision for calculating the axis offset
Solution Approach 2:
The patent extracts and eliminates the vehicle jacking requirement from the compensation process. By using only two measurement positions and computational averaging, the system removes the need for complex mechanical support structures, leaving a simpler procedure that can be performed with the vehicle on the ground
3Productivity
If two-position compensation method is used, then productivity is improved, but measurement precision deteriorates due to error introduction when wheels roll away from compensation position
Solution Approach 1:
The patent applies feedback by continuously monitoring the actual wheel rotational position during the alignment procedure and using this information to dynamically adjust or recalculate the compensation offset. This ensures that even if the wheels roll away from the original compensation position, the system can compensate for the change and maintain measurement accuracy
Solution Approach 2:
The patent performs preliminary compensation measurements at two fixed positions to establish a baseline offset value. This preliminary action creates a reference that can be used to correct subsequent measurements, allowing the system to maintain precision even when wheel positions change during the alignment procedure
Data Source
AI summary
A method for compensating axial misalignment between wheel-mounted alignment sensors and an axis of rotation for an associated wheel. The method compensates sensors mounted to each wheel of a vehicle simultaneously, without requiring jacking of the vehicle wheels above a supporting surface, and which only requires wheel rotational movement over an arc of 60 degrees or less. The method utilizes measurements of a change in a wheel toe angle and measurements of a change in a wheel camber angle, during a measured rotational movement of the wheel, to identify sinusoidal variation in the respective toe and camber angles during the wheel's rotational movement, from which a measure of axial misalignment between the wheel-mounted alignment sensor axis of rotation and the wheel axis of rotation is identified.