Patent attributes
A P-ECU controls an actuator which drives a shift control mechanism. An encoder signal acquisition unit acquires signals output from an encoder which detects a rotational angle of the actuator. A counter calculates a count value from the output signals of the encoder. An energization control unit controls energization to the actuator. A first phase-matching unit uses the Z-phase signal of the encoder to match the count value with energized phases so as to find a correspondence therebetween and a second phase-matching unit matches the count value with energized phases to find a correspondence therebetween without using the Z-phase signal of the encoder. If the first phase-matching unit detects an abnormality of the encoder, the second phase-matching unit subsequently performs phase matching.
