Patent ID: 8406962

Claim:
A method for determining an operating state of elements of a transmission, the method comprising: acquiring rotational speeds of both members constituting the elements; determining whether the rotational speeds of the members are the same; and determining that the elements are directly connected when the rotational speeds of the members are the same, and that the elements are disconnected or slip when the rotational speeds of the members are different; wherein the transmission to which the method is applied includes: a first planetary gear set including a first sun gear, a first ring gear, and a first carrier; a second planetary gear set including a second sun gear, a second ring gear, and a second carrier in which the second sun gear is directly connected to the first sun gear; a first brake restricting a rotation of the first ring gear; a second brake restricting a rotation of the second ring gear; a first clutch connecting/disconnecting the first carrier and the first ring gear; and a second clutch connecting/disconnecting the first carrier and the second ring gear, wherein the first carrier is directly connected to an engine, the first ring gear is directly connected to a first motor generator, the second sun gear is directly connected to a second motor generator, and the second carrier is directly connected to an output member; and wherein: a rotational speed of the second ring gear is determined in the acquiring of the rotational speeds and whether the acquired rotational speed of the second ring gear is 0 is determined in the determining sameness, when the transmission is in an input split mode performed by operation of the second brake, and the determining operation determines that the second brake that is one of the elements is operated when the rotational speed of the second ring gear is 0, and that the second brake slips or is released when the rotational speed thereof is not 0.