Patent ID: 6358184
Filing Date: 2002-03-19
Classification: B60W,F16H,Y10T

Abstract:
A method of controlling an on-coming clutch pressure during a garage shift of a motor vehicle automatic transmission to a target speed ratio, the transmission having an input shaft coupled to a vehicle engine through a fluidic torque converter, and the method comprising the steps of:filling the on-coming clutch at a determined fill pressure for a determined fill period; estimating an input torque applied to the transmission input shaft by the engine through the torque converter; applying the estimated input torque and a desired trajectory of said input shaft to an inverse dynamic model of the transmission to obtain an estimate of an on-coming clutch torque capacity for achieving said desired trajectory, and developing a feed-forward clutch pressure command based on the estimated clutch torque; developing on-coming clutch pressure in accordance with the feed-forward clutch pressure command; measuring a speed of the input shaft, and when initial engagement of the on-coming clutch produces a pull-down of said measured speed, adjusting the on-coming clutch pressure in accordance with a feed-back adjustment based on a deviation of the measured speed from an expected speed of the input shaft to compensate for errors in said inverse dynamic model; and raising the on-coming clutch pressure to complete the shift when the measured speed reaches a synchronous speed of the target speed ratio.