Control apparatus for controlling a shift operation in an automatic transmission

A control apparatus for controlling a shift operation in an automatic transmission performing a predetermined shift stage by maintaining respective plural friction engagement elements to be engaged or disengaged comprising:

• a fluid type transmitting mechanism (21) for transmitting an output from a vehicle driving power source to the automatic transmission;
• a lock-up clutch (22) disposed in parallel to the fluid type transmitting mechanism, the lock-up clutch (22) adapted to be engaged or not to be engaged for transmitting the output from the driving power source to the automatic transmission during the lock-up clutch at least being engaged;
• a lock-up clutch controlling means (50) for controlling the lock-up clutch to be engaged or not to be engaged in accordance with a vehicle driving condition;
• and
• a clutch-to-clutch shift operation controlling means (50) for generating a slip by reducing torque transmitted via an off-going friction engagement element and performing a shift operation by increasing torque transmitted via an on-coming friction engagement element, the off-going friction engagement element included in the plural friction engagement elements and switched from the engaged condition to the disengaged condition along with the shift operation from a shift stage to the other shift stage, and the on-coming friction engagement element also included in the plural friction engagement elements and switched from the disengaged condition to the engaged condition along with the shift operation from the shift stage to the other shift stage;
• the clutch-to-clutch shift operation controlling means including:
• an input shaft rotation speed obtaining means (step 1520) for obtaining a value corresponding to a rotation speed of an input shaft of the automatic transmission;
• an output shaft rotation speed obtaining means (step 1510) for obtaining a value corresponding to a rotation speed of an output shaft of the automatic transmission;
• and
• a slip amount controlling means (step 1650 and 1700) having a feedback controller for controlling the torque transmitted via the off-going friction engagement element for matching a control slip amount obtained based upon the values corresponding to the input shaft rotation speed and the output shaft rotation speed with a predetermined target slip amount and switching a gain of the feedback controller and phase characteristics thereof in response to the engagement condition of the lock-up clutch.