Method for controlling propulsion of a heavy-duty vehicle

A control unit arranged to control propulsion of a heavy-duty vehicle, where the heavy-duty vehicle comprises a drive shaft connected to a differential drive arrangement arranged to evenly distribute torque between a left wheel and a right wheel of a driven axle, the control unit comprising processing circuitry arranged to configure a nominal shaft slip of the drive shaft in dependence of a desired longitudinal wheel force to be generated by the driven axle, wherein a shaft slip is indicative of a difference between a current vehicle velocity and a vehicle velocity corresponding to the rotation speed of the drive shaft,

• obtain a rotation speed of the left wheel and a rotation speed of the right wheel, as function of a current shaft slip of the driven axle,
• estimate a peak shaft slip value associated with an open differential peak longitudinal force of the driven axle, based on the current shaft slip and on the corresponding obtained speeds of the left and right wheels, and
• control propulsion of the heavy-duty vehicle unit by setting the current shaft slip of the drive shaft based on the configured nominal shaft slip adjusted in dependence of the estimated peak shaft slip value.