Abstract: Alignment between the wheels of a vehicle is determined using a position determination system and includes indicating wheel positions on the vehicle with targets; imaging the targets to obtain locations of the wheel positions; and calculating a relationship between the front and rear wheels. Alignment is aided by calculating rear and front wheel tracks and comparing the calculated front and rear wheel tracks to a specified range for the front and rear wheel tracks. Also, right and left wheel bases can be calculated and the calculated right and left wheel bases to can be compared a specified range for the right and left wheel bases. Measures of offset and skew can also be obtained. A computer-implemented position determination system for determining alignment between the wheels of a vehicle is disclosed.

Abstract: Alignment between the wheels of a vehicle is determined using a position determination system and includes indicating wheel positions on the vehicle with targets; imaging the targets to obtain locations of the wheel positions; and calculating a relationship between the front and rear wheels. Alignment is aided by calculating rear and front wheel tracks and comparing the calculated front and rear wheel tracks to a specified range for the front and rear wheel tracks. Also, right and left wheel bases can be calculated and the calculated right and left wheel bases to can be compared a specified range for the right and left wheel bases. Measures of offset and skew can also be obtained. A computer-implemented position determination system for determining alignment between the wheels of a vehicle is disclosed.

Abstract: An apparatus and method for automatically identifying faults in the operation of a machine vision measuring systems provides an improved self-diagnostic capability for machine vision based metrology and tracking systems. The method and apparatus validate performance of tracking operations, and detect deterioration that may be caused by electronic noise, environmental contamination, etc. A mathematical model of the target visualized by the system is created and stored. A target is imaged in the field and fiducials of the target are identified. Centroid positions of detected fiducials of the imaged target are compared to the centroid positions of fiducials in the mathematical model. When a fiducial is obscured or dirty, its geometric characteristics (such as centroid, brightness, edge smoothness, area, or shape) differ from the true or idealized values of the characteristics.

Abstract: A method and apparatus are provided for determining a roll radius of a vehicle wheel for use in alignment and other diagnostic or maintenance operations. An optically scannable target is attached to a wheel of the vehicle. A first position measurement is made using a machine vision system, such as a three-dimensional aligner. The vehicle is rolled a short distance and a second position measurement is made. The linear and angular differences of the first and second position measurements are used to compute and store a roll radius value. Alignment values resulting from alignment of the motor vehicle are modified based on the roll radius value. A plane angle value may also be created and stored for use in adjusting the alignment values.

Abstract: An apparatus and method for determining axial stability compares measured wheel runout and axial instability parameters with prescribed tolerances to determine if the wheel suffers from excessive wheel play. Axial stability and runout is determined and displayed on a monitor screen such that an alignment technician can quickly assess both the degree of present wheel misalignment and the feasibility of attempting to perform a realignment operation without first repairing worn or damaged suspension parts. The attitude and location of a wheel are measured with the wheel set in a first position to determine a first vector having a predetermined relation to the wheel. The wheel is rolled back a number of degrees to a second position and the attitude and location thereof are measured to determine a second vector also having the predetermined relation to the wheel. Rearward axis parameters including a rearward rotational axis vector and a rearward runout vector are determined based on the first and second vectors.