ABNORMALITY DIAGNOSING DEVICE AND ABNORMALITY DIAGNOSING METHOD

• US 20180321319A1
• Filed: 05/01/2018
• Published: 11/08/2018
• Est. Priority Date: 05/02/2017
• Status: Active Grant

• Current Assignee: Fanuc Corporation
• Original Assignee: Fanuc Corporation
• Inventors: Morita, Yuuki, Takahashi, Kenji, Okita, Tadashi
• Granted Patent: US 10,444,288 B2
• Time in Patent Office: Days
• CPC Class Codes: G01R 31/343 in operation
• CPC Class Codes: G01R 31/346 Testing of armature or field windings
• CPC Class Codes: H02H 1/00 Details of emergency protective circuit arrangements
• CPC Class Codes: H02H 3/04 with warning or supervision in addition to disconnection, e.g. for indicating that protective apparatus has functioned watching of pilot wires H02H1/0084; protection of protective arrangements H02H7/008; indication of the state of electronic switches H03K17/18
• CPC Class Codes: H02H 7/0844 Fail safe control, e.g. by comparing control signal and controlled current, isolating motor on commutation error
• CPC Class Codes: H02P 29/0241 the fault being an overvoltage
• CPC Class Codes: H02P 29/10 for preventing overspeed or under speed
• CPC Class Codes: H02P 3/18 for stopping or slowing an ac motor

Abstract

An abnormality diagnosing device diagnoses a driving abnormality of a single motor driven by a plurality of motor driving devices. The plurality of motor driving devices calculate a plurality of voltage command values based on a speed command, and voltages are applied to a plurality of windings possessed by the motor based on the plurality of calculated voltage command values, thereby driving the motor. The abnormality diagnosing device is equipped with a command value difference calculating unit for calculating a difference between the plurality of voltage command values calculated by the plurality of motor driving devices, and a determination unit for determining the presence of an abnormality, when an absolute value of the difference calculated exceeds a first threshold value continuously for a predetermined time period.

Claims

1. An abnormality diagnosing device adapted to diagnose a driving abnormality of a single motor that is driven by a plurality of motor driving devices;

wherein the plurality of motor driving devices calculate a plurality of voltage command values on a basis of a position command or a speed command commanded from a numerical controller, and based on the plurality of calculated voltage command values, voltages are applied to a plurality of windings possessed by the motor, thereby driving the motor;

the abnormality diagnosing device comprising;

a command value difference calculating unit adapted to calculate a difference between the plurality of voltage command values calculated by the plurality of motor driving devices; and

a determination unit adapted to determine a presence of an abnormality, in an event that an absolute value of the difference calculated by the command value difference calculating unit exceeds a first threshold value continuously for a predetermined time period.

2. The abnormality diagnosing device according to claim 1, further comprising:

a rotational speed acquisition unit adapted to acquire a rotational speed value of the motor;

wherein the determination unit determines that there is an abnormality, if an absolute value of the rotational speed value exceeds a predetermined value, and the absolute value of the difference exceeds the first threshold value continuously for the predetermined time period.

3. The abnormality diagnosing device according to claim 1, wherein the determination unit determines that there is an abnormality, if an absolute value of at least one from among the plurality of voltage command values exceeds a second threshold value, and the absolute value of the difference exceeds the first threshold value continuously for the predetermined time period.

4. The abnormality diagnosing device according to claim 1, further comprising a notification unit adapted to issue a notifying alarm if the presence of an abnormality is determined by the determination unit.

5. The abnormality diagnosing device according to claim 1, further comprising a driving stop unit adapted to stop driving of the motor by the plurality of motor driving devices if the presence of an abnormality is determined by the determination unit.

6. The abnormality diagnosing device according to claim 1, wherein the abnormality diagnosing device is provided in the motor driving device.

7. An abnormality diagnosing method for diagnosing a driving abnormality of a single motor that is driven by a plurality of motor driving devices;

wherein the plurality of motor driving devices calculate a plurality of voltage command values on a basis of a position command or a speed command commanded from a numerical controller, and based on the plurality of calculated voltage command values, voltages are applied to a plurality of windings possessed by the motor, thereby driving the motor;

the abnormality diagnosing method comprising;

a command value difference calculating step of calculating a difference between the plurality of voltage command values calculated by the plurality of motor driving devices; and

a determining step of determining a presence of an abnormality, in an event that an absolute value of the difference calculated by the command value difference calculating step exceeds a first threshold value continuously for a predetermined time period.

8. The abnormality diagnosing method according to claim 7, further comprising:

a rotational speed acquiring step of acquiring a rotational speed value of the motor;

wherein the determining step determines that there is an abnormality, if an absolute value of the rotational speed value exceeds a predetermined value, and the absolute value of the difference exceeds the first threshold value continuously for the predetermined time period.

9. The abnormality diagnosing method according to claim 7, wherein the determining step determines that there is an abnormality, if an absolute value of at least one from among the plurality of voltage command values exceeds a second threshold value, and the absolute value of the difference exceeds the first threshold value continuously for the predetermined time period.

10. The abnormality diagnosing method according to claim 7, further comprising a notifying step of issuing a notifying alarm if the presence of an abnormality is determined by the determining step.

11. The abnormality diagnosing method according to claim 7, further comprising a driving stop step of stopping driving of the motor by the plurality of motor driving devices if the presence of an abnormality is determined by the determining step.