Patent ID: 8386139

Claim:
A control device for an automatic transmission for a vehicle, the transmission comprising a transmission mechanism that comprises a first frictional engagement element and a second frictional engagement element and is engaged in a shift operation between a first state in which the first frictional engagement element is disengaged and the second frictional engagement element is engaged and a second state in which the first frictional engagement element is engaged and the second frictional engagement element is disengaged, the transmission mechanism having a characteristic that a minute slip is caused to occur at the second frictional engagement element by loosening engagement of the second frictional engagement element in the first state, and the minute slip is terminated as the first frictional engagement element is engaged, the device comprising: a programmable controller programmed to: perform a determination as to whether or not a shifting operation from the first state to the second state is to be performed in such a way that a torque phase in which engaging pressures of the first frictional engagement element and the second frictional engagement element are varied without varying a speed ratio of the transmission mechanism and an inertia phase in which speed ratio of the transmission mechanism is actually varied are performed in this order; when the determination is affirmative, control the transmission mechanism to cause a minute slip at the second frictional engagement element by loosening engagement of the second frictional engagement element in the first state, terminate the minute slip at the second frictional engagement element by gradually engaging the first frictional engagement element, learn a value representing an engaging state variation in the first frictional engagement element between a time point at which engagement of the first frictional engagement element starts and a time point at which the minute slip of the second frictional engagement element is terminated; and correct an engaging force with which the first frictional engagement element is engaged in a shift operation executed to shift from the first state to the second state based upon the value representing the engaging state variation having been learned.