Keywords
Citation
(2004), "Precision in automotive wheel alignment", Sensor Review, Vol. 24 No. 1. https://doi.org/10.1108/sr.2004.08724aaf.005
Publisher
:Emerald Group Publishing Limited
Copyright © 2004, Emerald Group Publishing Limited
Precision in automotive wheel alignment
Precision in automotive wheel alignment
Keywords: Automotive, BMW
In the BMW plant in Dingolfing, Germany, a range of vehicles is manufactured including sports models, the off road X5 and the new series seven saloons. Wheel alignment machinery must cope with a wide range of tyre sizes. UK manufacturer MERILab supplied a non-contacting system where laser cameras are positioned by Lenze servo motors and Lenze drives.
In operation the vehicle is driven onto the machine with the road wheel rotating slowly on rollers. Each of the four wheels has two laser cameras to measure toe in and camber. The cameras project a flat plane of laser light with a width of 125 mm and can measure all points on the tyre sidewall with a remarkable accuracy of 20 µm. The cameras are fitted to a plate, which is positioned by Lenze servo motors and drives. To prevent the position being lost in the event of a power failure, the vertical drives which might fall under gravity are equipped with servo brake motors.
Additional servo drives control cameras to record the wheel arch position and to set the chassis central to the machine. Laser readings are used to generate a three-dimensional model of all four wheels including the exact centres, and the wheel arches. MERILab software calculates the alignment errors and displays them for operators positioned beneath the vehicle.
High-speed transmission of data is required to achieve accuracy in the servo driven laser camera positions. A resolver on the motors is connected to the drive. Data transmission from the drive to the alignment computer is by CAN system bus, which is integrated at no extra cost in the drive. In addition, the Lenze drives are networked through PROFIBUS and PROFIBUS plug-in modules on the drives, matching the fieldbus needs of the plant.
In addition to modelling to an accuracy of 20 µm, the machine is able to achieve toe in accuracy of 1/4 min of arc and ride height to less than 0.1 mm. This is all done in a 4min cycle, achieved through MERILab technology and Lenze servo systems.
For more information, please contact: Geoff Spear at Lenze Ltd, Caxton Road, Bedford, MK41 OHT. Tel: 01234 321227; Fax: 01234 321318; E-mail: gspear@lenze.co.uk