Patent ID: 8755981

Claim:
A method of controlling an automatic transmission having a clutch, the method comprising: providing a control module operable to control the operation of the transmission, wherein the control module is configured for: estimating an expected coefficient of friction of the clutch; estimating a value of an expected torque required to maintain a constant slip of the clutch for a current input torque applied to the transmission; determining a value of an actual torque applied to the clutch to maintain the constant slip of the clutch at the current input torque; calculating an actual coefficient of friction of the clutch, wherein the actual coefficient of friction of the clutch is calculated from the equation: μ act = ( τ a ⁢ ⁢ ct τ e ⁢ ⁢ xp ) ⁢ μ ex ⁢ ⁢ p wherein μ act is the actual coefficient of friction of the clutch, μ exp is the expected coefficient of friction of the clutch, τ act is the value of the actual torque applied to the clutch to maintain the constant slip of the clutch, and τ exp is the value of the expected torque required to maintain the constant slip of the clutch; and adjusting an initial value of a feed forward torque command applied to the clutch based on the calculated actual coefficient of friction of the clutch to define a revised value of the feed forward torque command.