Motor control apparatus

• US 20070182353A1
• Filed: 04/04/2007
• Published: 08/09/2007
• Est. Priority Date: 06/03/2002
• Status: Active Grant

• Current Assignee: DENSO Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: DENSO Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kobiki, Yasushi, Fujiki, Kenichi, Inoue, Yuji, Kamio, Shigeru, Amamiya, Sumiko, Ohshima, Keijiro
• Granted Patent: US 7,609,012 B2
• Time in Patent Office: Days
• US Class Current: 318/466
• CPC Class Codes: F16H 2061/326 Actuators for range selection, i.e. actuators for controlling the range selector or the manual range valve in the transmission
• CPC Class Codes: F16H 61/32 Electric motors actuators or related electrical control means therefor
• CPC Class Codes: H02P 25/08 Reluctance motors
• CPC Class Codes: H02P 25/092 Converters specially adapted for controlling reluctance motors
• CPC Class Codes: H02P 25/0925 wherein the converter comprises only one switch per phase
• CPC Class Codes: H02P 8/42 characterised by non-stepper motors being operated step by step
• CPC Class Codes: Y10T 74/2003 Electrical actuator

Abstract

In an automatic transmission position control by a motor, it is determined whether the present instant belongs to a starting period, that is, the present instant is immediately after resetting of a control unit or application of power to it. If it is the starting period, an actual shift position that is detected from an output of an output shaft sensor for detecting a rotation position of a motor is set as an instructed shift position. With this measure, even if the control unit is reset for a certain reason while the vehicle is running, the instructed shift position is not changed in association with the resetting. This prevents trouble that the shift position is switched contrary to the intention of the driver, whereby the reliability of a position switching control can be increased.

Claims

1. A motor control apparatus comprising:

an encoder for producing a pulse output signal in synchronism with rotation of a rotor of a motor that rotates a control object;

control means for rotating the rotor to a target position that is set by target position setting means by detecting a rotation position of the rotor on the basis of a count of the output signal of the encoder and sequentially switching a current supply phase of the motor; and

a nonvolatile memory for storing the target position that is set by the target position setting means,

wherein at starting the control means sets, as a target position of starting, the target position that is stored in the nonvolatile memory.

2. The motor control apparatus according to claim 1, wherein the nonvolatile memory maintains storage of the target position being supplied with power from a battery while the control means is not supplied with power, and

wherein the control means comprises means for detecting removal of the battery, and sets a predetermined target position as the target position of starting when removal of the battery is detected.

3. The motor control apparatus according to claim 2, wherein data of the target position stored in the nonvolatile memory is different from an initial value that is set when power is applied to the nonvolatile memory, and

wherein the control means determines whether the battery has been removed on the basis of whether the data of the target position stored in the nonvolatile memory coincides with the initial value.

4. The motor control apparatus according to claim 3, wherein when removal of the battery is detected, at starting the control means rotates the rotor toward the predetermined target position to cause butting at a limit position thereof and thereby learns the limit position.

6. The motor control apparatus according to claim 1, wherein the motor is a switched reluctance motor.

7. The motor control apparatus according to claim 1, wherein the control object is a position switching mechanism for switching between a parking position and another position of a vehicle.

5. A motor control apparatus comprising:

an encoder for producing a pulse output signal in synchronism with rotation of a rotor of a motor that rotates a control object;

control means for rotating the rotor to a target position that is set by target position setting means by detecting a rotation position of the rotor on the basis of a count of the output signal of the encoder and sequentially switching a current supply phase of the motor; and

an output shaft sensor for detecting a rotation position of an output shaft of the motor or position information that is correlated with it,

wherein the control means sets, as a target position of starting, a rotation position that is detected by the output shaft sensor at starting.