Vehicle traction controller with torque and slip control

A method of controlling vehicle directional stability and the traction of wheels of said vehicle, which is being driven over a surface, said method comprising in combination, the steps of:

• (a) generating a rotational velocity value indicative of the rotational velocity of said vehicle;
• (b) selecting, as a function of the rotational velocity value, from the wheels of said vehicle, a first pair of wheels to be controlled by application of a braking force upon said wheels, said pair of wheels both existing on the same side of said vehicle;
• (c) comparing said rotational velocity value to a predefined rotational velocity range indicative of a range of acceptable rotational velocity values;
• and
• (d) responding to said rotational velocity value being outside of said rotational velocity range by,
• for each driven wheel of said vehicle, determining if said wheel is skidding and responding to skidding of said wheel by changing braking force applied to said wheel;
• and
• for all wheels of said vehicle, determining if said wheel is one of said first pair of wheels and if so, then generating a wheel torque value which is indicative of a braking force to be applied independently of driver initiated braking to said wheel, calculating, as a function of an estimated coefficient of road surface friction, a minimum wheel torque value and a maximum wheel torque value, said minimum wheel torque value and said maximum wheel torque values together defining a range of wheel torque values which may be applied to one of said first pair of wheels, comparing said wheel torque value to said minimum wheel torque value and to said maximum wheel torque value, and increasing said wheel torque value to a value substantially equal to said minimum wheel torque value if said wheel torque value is less than said minimum wheel torque value, and decreasing said wheel torque value to a value substantially equal to said maximum wheel torque value if said wheel torque value is greater than said maximum wheel torque value.