Method and apparatus controlling cross-axis oscillations in a vehicle traction controller

A method of controlling across-the-axis oscillations in a vehicle which utilizes a traction controller, comprising:

• determining if a frictional resistance of the surface below each wheel of a pair of driving wheels differs by more than a predetermined frictional difference value, and determining the rotational speed of each of the driving wheels;
• responding to the frictional resistance of the surface below each of the wheels of the pair of driving wheels differing by more than the predetermined frictional difference value by determining if both wheels of the pair of driving wheels are spinning;
• responding to spinning of both wheels of the pair of driving wheels by determining an inertia torque value which is indicative of an inertia torque of the vehicle drivetrain and driving wheels,
• comparing said inertia torque value to a predetermined torque value, and
• if said inertia torque value is greater than said predetermined torque value, then applying a first braking force to the driving wheel having the higher rotational speed of the two driving wheels, and applying a second braking force to the other driving wheel, said second braking force being proportional to said first braking force;
• responding to the spinning of only one driving wheel by determining the amount of engine power desired by a driver of the vehicle by determining the position of the vehicle gas pedal;
• comparing the amount of desired power to a predetermined power value;
• if said amount of desired power exceeds said predetermined power value then setting an engine torque value which determines the amount of torque produced by the vehicle engine to a first torque value and setting a braking force value which determines the amount of braking force to be applied to the wheels of the vehicle to a third braking force value, and determining said inertia torque value, comparing said inertia torque value to said predetermined torque value, and if said inertia torque value is greater than said predetermined torque value, then applying a fourth braking force to the driving wheel having the higher rotational speed of the two driving wheels, and applying a fifth braking force to the other driving wheel, said fifth braking force being proportional to said fourth braking force;
• if said amount of desired power does not exceed said predetermined power value then determining said inertia torque value, comparing said inertia torque value to said predetermined torque value, and if said inertia torque value is greater than said predetermined torque value, then applying a sixth braking force to the driving wheel having the higher rotational speed of the two driving wheels, and applying a seventh braking force to the other driving wheel, said seventh braking force being proportional to said sixth braking force.

Apparatus for controlling spinning of driving wheels of a vehicle, during operation of the vehicle on surfaces with variable coefficients of friction comprising, in combination:

• means for estimating the coefficient of friction of the surface beneath each of the driving wheels and determining a first rotational speed value which corresponds to the rotational speed of a first of said driving wheels and a second rotational speed value which corresponds to the rotational speed of a second of said driving wheels;
• means, responsive to the coefficient of friction of the surface beneath each of the driving wheels differing by more than a predetermined frictional difference value, for determining, as a function of said first rotational speed value and said second rotational speed value, if both driving wheels are spinning;
• and
• means, responsive to spinning of both driving wheels, for determining an inertia torque value indicative of an inertia torque of the combination of the drivetrain and driving wheel, comparing said inertia torque value to a predetermined torque value, if said inertia torque value exceeds said predetermined torque value then reducing the spinning of the driving wheels by generating a first braking force value corresponding to the driving wheel having the higher rotational speed of the two driving wheels, and generating, as a function of said first braking force value, a second braking force value corresponding to the driving wheel having the lower rotational speed of the two driving wheels, said second braking force value corresponding to a braking force which is smaller in magnitude than said first braking force value, and substantially simultaneously applying braking forces corresponding to said first and said second braking force values, to each of said driving wheels.