Guidelines to Specify a Camera for Computer Vision Measurement of Vehicle Suspension Alignment Angles Based on the Desired Sensibility

A method to calculate the sensibility of a Computer Vision measurement system is presented in this paper. The specific mensuration done is for car wheel inclination. It will be shown that an equipment using cameras and no other clamp or accessory attached to the wheels to help the procedure to obtain angles from the steering suspension alignment by means of the wheel's images is a viable idea, but not, nowadays technologically realizable.

I. Introduction

In the issue automobile suspension geometry there are three main angles of alignment [1] that must periodically be measured and adjusted if necessary in a specialized repair shop. That procedure guarantees saving of the tires and, the most important, safety for the users of the vehicle. The main angles are called: toe , camber , caster . The first one is the measurement of the angle between the axial center line in a top view of a car and the center line of the wheel, the angle corresponds to the inclination of the wheel for a center line in a front view of the auto and the is referred to an included angle between the center line of the vehicle in a lateral view and the line which passes through the steering pivot of the suspension system. It is represented at the “Fig. 1” the three main steering suspension angles. Both toe and camber angles can be directly measured by a machine vision configuration with two cameras, but the caster is hidden by the wheel and should be measured indirectly by means of a formula [1] that uses camber values before acquired in a standard trivial procedure [2]. Figure 1. Three main angles of the vehicle suspension system.