STATE IDENTIFICATION DEVICE, STATE IDENTIFICATION METHOD AND MECHANICAL DEVICE

• US 20190324428A1
• Filed: 04/12/2019
• Published: 10/24/2019
• Est. Priority Date: 04/20/2018
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: SAKAI, Hideo, MAEDA, Masaaki, SAKURAI, Yuichi, TAKAHASHI, Masayoshi
• Granted Patent: US 10,845,794 B2
• Time in Patent Office: Days
• CPC Class Codes: E02F 9/264 Sensors and their calibration for indicating the position of the work tool
• CPC Class Codes: G05B 19/188 characterised by special applications and not provided for in the relevant subclasses, (e.g. making dies, filament winding)
• CPC Class Codes: G05B 19/406 characterised by monitoring or safety G05B19/19 takes precedence
• CPC Class Codes: G05B 19/4183 characterised by data acquisition, e.g. workpiece identification
• CPC Class Codes: G05B 2219/24053 Diagnostic of controlled machine
• CPC Class Codes: G05B 2219/33285 Diagnostic
• CPC Class Codes: G05B 2219/35086 Machining feature extraction, geometry and machining parameters
• CPC Class Codes: G05B 23/0281 Quantitative, e.g. mathematical distance; Clustering; Neural networks; Statistical analysis
• CPC Class Codes: G05B 23/0283 Predictive maintenance, e.g. involving the monitoring of a system and, based on the monitoring results, taking decisions on the maintenance schedule of the monitored system; Estimating remaining useful life [RUL] preventive maintenance, i.e. planning maintenance according to the available resources without monitoring the system G06Q10/06

Abstract

A state identification device includes: a feature amount extraction unit that extracts a feature amount from physical data of a machine tool unit which shifts to a plurality of operation states; a feature amount storage unit in which a region is provided as a storage destination of the extracted feature amount for each of the plurality of operation states to which the machine tool unit shifts; a similarity calculation unit that calculates a similarity between the extracted feature amount and a feature amount stored in the feature amount storage unit; a state determination unit that determines an operation state of the machine tool unit based on the calculated similarity; and a storage destination determination unit that determines the region serving as the storage destination of the extracted feature amount based on a determination result of the state determination unit.

Claims

1. A state identification device, comprising:

a feature amount extraction unit that extracts a feature amount from physical data of a machine tool unit which shifts to a plurality of operation states;

a feature amount storage unit in which a region is provided as a storage destination of the extracted feature amount for each of the plurality of operation states to which the machine tool unit shifts;

a similarity calculation unit that calculates a similarity between the extracted feature amount and a feature amount stored in the feature amount storage unit;

a state determination unit that determines an operation state of the machine tool unit based on the calculated similarity; and

a storage destination determination unit that determines the region serving as the storage destination of the extracted feature amount based on a determination result of the state determination unit.

2. The state identification device according to claim 1, wherein

the feature amount extraction unit extracts a feature amount from the physical data detected when the machine tool unit shifts to a stop state, and

the feature amount storage unit stores the feature amount extracted from the physical data detected when the machine tool unit shifts to the stop state as basic data in the region corresponding to the stop state.

3. The state identification device according to claim 1, wherein

the machine tool unit shifts to at least one of three states, which include a stop state, an idle state, and a work state, as the operation state, and

the feature amount storage unit is provided with the region corresponding to each of the stop state, the idle state, and the work state.

4. The state identification device according to claim 1, wherein

the region provided in the feature amount storage unit corresponding to each of the plurality of operation states has an upper limit number for the feature amount to be stored, and

the feature amount storage unit erases only one stored feature amount and then stores the extracted feature amount when the upper limit number of pieces of the feature amount are stored in the region determined as the storage destination of the extracted feature amount.

5. The state identification device according to claim 4, wherein

the region provided in the feature amount storage unit corresponding to each of the plurality of operation states has the upper limit number differently.

6. The state identification device according to claim 1, wherein

the feature amount storage unit is provided with the region that does not correspond to any of the plurality of operation states, and

the feature amount storage unit stores the extracted feature amount in the region that does not correspond to any of the plurality of operation states when the operation state of the machine tool unit is not determined.

7. The state identification device according to claim 2, further comprising:

a deletion unit that deletes the feature amount other than the basic data from the feature amount storage unit.

8. The state identification device according to claim 7, wherein

the deletion unit deletes the feature amount other than the basic data from the feature amount storage unit when the state determination unit continuously determines for a predetermined number of times that the operation state of the machine tool unit is the stop state.

9. A state identification method of a state identification device, comprising:

extracting a feature amount from physical data of a machine tool unit which shifts to a plurality of operation states;

calculating a similarity between the extracted feature amount and a feature amount stored in a feature amount storage unit;

determining an operation state of the machine tool unit based on the calculated similarity; and

determining a region in the feature amount storage unit that serves as a storage destination of the extracted feature amount based on a determination result by determining the operation state, wherein

the feature amount storage unit is provided with a region that serves as a storage destination of the extracted feature amount for each of the plurality of operation states to which the machine tool unit shifts.

10. A mechanical device, comprising:

a machine tool unit that shifts to a plurality of operation states;

a sensor unit that detects physical data of the machine tool unit;

a feature amount extraction unit that extracts a feature amount from the detected physical data;

a feature amount storage unit in which a region is provided as a storage destination of the extracted feature amount for each of the plurality of operation states to which the machine tool unit shifts;

a similarity calculation unit that calculates a similarity between the extracted feature amount and a feature amount stored in the feature amount storage unit;

a state determination unit that determines an operation state of the machine tool unit based on the calculated similarity; and

a storage destination determination unit that determines the region serving as the storage destination of the extracted feature amount based on a determination result of the state determination unit.