Traction control using dynamic tire friction potential

摘要

A method for controlling slip of a driven wheel on low friction surfaces includes determining the current magnitude of static tire friction potential, current magnitude of maximum dynamic tire friction potential, and magnitude of tire torque demanded by an operator of the vehicle. A lower magnitude of commanded tire force is set less than the estimated current magnitude of static tire friction potential. The magnitude of demanded wheel torque and the estimated current magnitude of maximum dynamic tire friction potential are used to set an upper magnitude of commanded tire force. The magnitude of commanded tire force is changed in a sequence of saw-tooth pulses, each pulse including an increasing ramp of tire force from the lower commanded tire force to the upper commanded tire force, the ramp having a predetermined slope, and a step that reduces the magnitude of commanded tire force between each pulse to the lower commanded tire force. An adaptation mechanism is used to adjust the saw-tooth signal parameters with respect to road condition changes.