Control apparatus for an automatic transmission of a vehicle and control method thereof

摘要

A gear ratio of the automatic transmission is controlled by changing a speed ratio between an input-side rotating member to which the driving force from an engine is transmitted and an output-side rotating member through which the driving force is transmitted to driven wheels. The control apparatus has a vehicle speed detecting part for detecting the speed of the vehicle; a a road gradient estimating part for estimating the gradient of road; a gradient determining part for determining whether or not the road gradient estimated by a road gradient estimating part is beyond a predetermined threshold value; a vehicle speed determining part for determining a target vehicle speed based on the vehicle speed detected by the vehicle speed detecting part, when it is determined by the gradient determining part that the road gradient is beyond the predetermined threshold value; and a control part for controlling the gear ratio so that the vehicle speed can match up to the target vehicle speed determined by the vehicle speed determining part, when it is determined by the gradient determining part that the road gradient is beyond the predetermined threshold value.