Regenerative braking method

In a vehicle with a first set of first and second wheels coupled to an electric drive system capable of providing regenerative braking and a second set of third and fourth wheels, wherein the vehicle dynamically adjusts a brake proportioning between the first and second sets responsive to a determined wheel speed difference between the first and second sets, the improvement comprising a regenerative braking control method according to the steps of:

• measuring first, second, third and fourth speeds of the first, second, third and fourth wheels;
• normalizing the first, second, third and fourth speeds;
• for each wheel of one of the first and second sets, determining a wheel speed set-off value inversely relational to a commanded brake torque and a wheel deceleration;
• determining modified normalized wheel speeds for each wheel of said one of the first and second sets responsive to the normalized wheel speeds and the wheel-speed set-off values;
• and
• determining the wheel speed difference between the first and second sets responsive to the modified normalized wheels speeds of said one of the first and second sets and the normalized wheel speeds of the other of the first and second sets, wherein
• the dynamic adjusting of brake proportioning between the first and second sets responsive to the determined wheel speed difference is responsive to the speed set-off values to increase brake torque load on the first and second wheels, increasing an amount of braking achieved regeneratively.