Method of controlling driving force of vehicle

A method of controlling a driving force of a vehicle, comprising:

• performing a first estimation in which a first maximum road surface frictional coefficient is estimated based on a driving stiffness defined by a micro slip ratio and the driving force of drive wheels, in a first driving state where the vehicle travels straight at a constant acceleration;
• performing a second estimation in which a second maximum road surface frictional coefficient is estimated based on a steering reaction force detected by an electric power steering device, in a second driving state different from the first driving state and where the vehicle is steered;
• performing a third estimation in which a third maximum road surface frictional coefficient is estimated to be a given value in a third driving state different from the first and second driving states and where a temperature of outdoor air is above a determination temperature;
• and
• performing a driving force control in which the driving force of the drive wheels is controlled to settle within a friction circle defined by each of the maximum road surface frictional coefficients and a ground contact load of the drive wheels.