Product category:
Stepper and Servo Drives, Motors, Controls
News Release from: Lenze | Subject: Servo systems
Edited by the Engineeringtalk Editorial
Team on 10 September 2003
Servo-based system aligns wheels on BMW
lines
On BMW automobile production lines, noncontact wheel measuring systems with positioning by Lenze servo systems provide precise wheel alignment.
On BMW automobile production lines, noncontact wheel measuring systems with positioning by Lenze servo systems provide precise wheel alignment In factories in Germany and the UK, these end-of-line wheel alignment machines automatically create a computer model of the four car wheels in relation to the chassis
This article was originally published on Engineeringtalk on 2 Nov 2001 at 8.00am (UK)
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This allows the operators to easily set the alignment to the vehicles centre line plus to adjust toe-in and camber.
In the BMW plant in Dingolfing, Germany, a range of vehicles is manufactured including sports models, the off-road X5 and the new series 7 saloons.
Wheel alignment machinery must cope with a wide range of tyre sizes.
UK manufacturer MERILab supplied a noncontact 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 125mm and can measure all points on the tyre sidewall with a remarkable accuracy of 20um.
The cameras are fitted to a plate, which is positioned by Lenze servomotors 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.
As well as modelling to an accuracy of 20um, the machine is able to achieve a toe-in accuracy of 0.25arc-min and ride height to less than 0.1mm.
This is all done in a 4min cycle, achieved through MERILab technology and Lenze servo systems. Request a free brochure from Lenze ...
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