Patent ID: 11946773
Assignee: DENSO CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 11:
12. A control unit comprising:
a detection device comprising:
a multi-turn detection unit configured to continue detection of a rotation position of multiple rotations of a detection object driven by a motor without supply of electric power from outside;
a position detector configured to detect a rotation position in one rotation of the detection object;
a multiple rotation position calculator configured to calculate multiple rotation position information related to the rotation position of multiple rotations based on a detection value of the multi-turn detection unit, the multiple rotation position information being a count value that divides one rotation of the detection object by an integer of 1 or more; and
an angle calculator configured to calculate rotation angle information related to the rotation position in one rotation of the detection object based on a detection value of the position detector, wherein
the multi-turn detection unit is disposed at a position different from a position of the motor,
the multiple rotation position information is a count value either counted up or down according to a rotation direction by a number of n, where n is the integer of 1 or more, in one rotation of the detection object, and
the multiple rotation position calculator is configured to count the count value as a number m between an upper limit value and a lower limit value, where m is an integer of 2n or more, and, upon having the count value reaching the upper limit value, count up the count value to the lower limit value in a subsequent count up and, upon having the count value reaching the lower limit value, count down the count value to the upper limit value in a subsequent count down, and
a controller for controlling a drive of a motor, wherein
the detection device or the controller includes an absolute position calculator configured to calculate an absolute position representing a displacement amount of the detection object from a reference position based on the multiple rotation position information and the rotation angle information,
a motor rotation angle sensor configured to detect a rotation angle of the motor, wherein
the absolute position calculator calculates the absolute position based on (i) the multiple rotation position information based on the detection value of the multi-turn detection unit and (ii) the rotation angle information based on the detection value of the motor rotation angle sensor, and
the controller includes an abnormality monitoring unit configured to monitor abnormality based on a detection object side absolute position and a motor side absolute position, wherein
the abnormality monitoring unit determines, when (i) a difference between the detection object side absolute position and the motor side absolute position is equal to or greater than an abnormality threshold value and (ii) no abnormality history is recorded for the detection device nor the controller, that a shift has occurred at a connection between a detection target and a motor.