Yaw Gain Optimization

Abstract: eLSDs (Electronically controlled Limited Slip Differentials) are showing a more popular trend in the passenger vehicle industry. Haldex Traction in Landskrona, mostly famous for their limited slip couplings for AWD (all wheel driven) vehicles, has now started to develop a differential coupling for a FWD (front wheel driven) car. The control of an eLSD in a FWD car affects the traction capability as well as the handling behaviour. The traction and handling capability was before the start of this project controlled using a slip controller and a yaw controller. The slip controller measures the driven wheels angular velocity and compares it to the vehicles velocity and then control the differential accordingly. Another way to control the differential could be to control the angular velocity around the cars vertical axis when driving in a turn. If the car is over steering more than the driver wants the differential might be able to help. This control system would be called “yaw rate control” or abbreviated “yaw control”.