A slip control system of a lockup torque converter includes a pre-compensator
that
pre-compensates for a target slip-rotation speed to produce a target slip-rotation
speed correction value. A feedback compensator is provided to feedback-control
an engagement capacity of a lock-up clutch based on a deviation between the target
slip-rotation speed correction value and an actual slip-rotation speed to bring
the actual slip-rotation speed closer to the target slip-rotation speed. Also provided
is a dead-time processing section that compensates for the target slip-rotation
speed correction value to reflect a dead time of dynamic characteristics peculiar
to the slip control system in the target slip-rotation speed correction value.
The dead-time compensated output is fed to the feedback compensator. The dead time
is variable in accordance with a predetermined dead time characteristic.
