Vorrichtung und Verfahren zur Steuerung eines Automatikgetriebes

摘要

A control apparatus for an automatic transmission includes a shift control section (20) configured to perform a shift of the automatic transmission by engaging a first friction-engagement element and releasing a second friction-engagement element; and a judder judging section configured to judge an occurrence of judder due to self-exited vibration. The shift control section is configured to judge whether or not a progress of the shift is during an inertia phase. The judder judging section calculates a characteristic-gradient index value (”t2/ ”t1) which is a value obtained by quantifying a phenomenon that appears as a relative rotational speed between input and output of the first friction-engagement element becomes reduced with a progress of the inertia phase. The phenomenon appears in a different way in dependence upon whether a relational characteristic of a friction coefficient of the first friction-engagement element with respect to the relative rotational speed is a positive-gradient characteristic or a negative-gradient characteristic. The judder judging section determines that the judder has occurred, when the characteristic-gradient index value indicates that the phenomenon has appeared due to the negative-gradient characteristic.