Patent ID: 8504262

Claim:
A control apparatus for an automatic transmission, the automatic transmission being connected with an internal combustion engine that is mounted on a vehicle and including a plurality of gears and a plurality of hydraulic clutches, the control apparatus comprising: a torque calculator configured to calculate a torque required during a speed change for a hydraulic clutch at a target speed stage among the hydraulic clutches based on an output torque of the internal combustion engine; a supply fluid pressure calculator configured to obtain, from the calculated torque, a supply fluid pressure to be supplied to the hydraulic clutch at the target speed stage by using a clutch friction coefficient; a fluid supplier configured to supply the obtained supply fluid pressure to the hydraulic clutch at the target speed stage to perform the speed change for an output of the internal combustion engine through a gear corresponding to the target speed stage; a clutch plate temperature estimating device configured to estimate a plate temperature of the hydraulic clutch; and a fluid pressure correcting device configured to correct the supply fluid pressure based on the estimated plate temperature, wherein the fluid pressure correcting device is configured to calculate a correction coefficient based on the estimated plate temperature and configured to multiply the clutch friction coefficient by the calculated correction coefficient to correct the clutch friction coefficient, to correct the supply fluid pressure, wherein the fluid pressure correcting device is configured to calculate an added fluid pressure to be added to the supply fluid pressure in accordance with a gear ratio, and wherein, when the gear ratio is equal to or smaller than a predetermined value, the fluid pressure correcting device calculates an add correction coefficient based on the estimated plate temperature and multiplies the added fluid pressure by the add correction coefficient to correct the supply fluid pressure.