Patent ID: 7774120

Claim:
A control apparatus for an automatic transmission of a vehicle, the control apparatus comprising: a primary pulley including a movable pulley, the primary pulley being connected with an input; a secondary pulley including a movable pulley, the secondary pulley being connected with an output; a belt wound around the primary pulley and the secondary pulley; a shift control valve configured to regulate a hydraulic pressure acting on the movable pulley of the primary pulley; a step motor configured to be moved to a position in accordance with a target pulley ratio between the primary pulley and the secondary pulley; a servo link connected to the step motor, the movable pulley of the primary pulley, and the shift control valve, and arranged to move the movable pulley of the primary pulley through the shift control valve in accordance with the position of the step motor; an actual pulley ratio sensing section configured to sense an actual pulley ratio between the primary pulley and the secondary pulley; and a control section configured to control the step motor in accordance with the target pulley ratio and the actual pulley ratio sensed by the actual pulley ratio sensing section, the control section including: a target pulley ratio setting section configured to set the target pulley ratio; a normal control section configured to perform a normal control to actuate the step motor at a first speed by using a feedback control including an integral control in accordance with the target pulley ratio and the actual pulley ratio; a high speed control section configured to perform a high speed control to actuate the step motor at a second speed higher than the first speed by an open loop control based on the target pulley ratio; a judgment section configured to judge whether there is a high speed operation request to perform a shift operation at a high speed; and a switch section configured to select the normal control performed by the normal control section at a normal condition, and to switch to the high speed control performed by the high speed control section when a switch start condition is satisfied, the switch start condition including a first condition that the judgment section judges there is the high speed operation request.