Low-cycle time steering wheel angle & wheel alignment test using machine vision
Publication Date: 2011-Sep-13
The IP.com Prior Art Database
Page 01 of 2
100% Dynamic Clearvision Audit Check
"Clearvision" is the term used to describe the steering wheel angle when driving down the road. Clearvision is a function (output) of the wheel alignment process - the more accurate the vehicles wheels are set, the more accurate
Clearvision would be.
A current method for checking Clearvision is to
sample 1 vehicle per hour of production, and
perform a drive audit with a specially-designed inclinometer that measures the clearvision angle. This audit process has significant drawbacks mainly that it attempts to provide feedback on a process that has significant vehicle-level dependencies (ie, changes vehicle-to-vehicle) with a population-level control method. Additionally, because of the time it takes to perform the audit process, very low sampling rates can result in long reaction time to out-of-specification or out-of-control readings.
The key factor, however, that results in the need to perform a drive audit is called Hysteresis. Steering system hysteresis (also called Deadband) is the addition of all of the tolerances in the steering system. It results in a small window where the steering wheel is turned, but the front wheels do not. This can vary by vehicle, but is typically within 4 and 10 degrees of steering wheel angle. Hysteresis, up to now, has never been accounted for in any machine-based Clearvision audit.
A method is proposed to add a feature to a specialized wheel alignment audit system that would enable a significant...