# US 2021/0173383 A1 · Unit space generating device, plant diagnosing system, unit space generating method, plant diagnosing method, and program

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2021/0173383 A1
- Document ID: US20210173383A1
- Status: Published application
- Kind: A1
- Application number: 16/769,738
- Filed: 2018-12-18
- Published: 2021-06-10
- Earliest claimed: 2017-12-21
- Assignees: Mitsubishi Hitachi Power Systems, Ltd.
- Applicants: Mitsubishi Hitachi Power Systems, Ltd.
- Inventors: Ichiro NAGANO; Mayumi SAITO; Keiji EGUCHI
- Web page: https://patentgrep.com/patent/US20210173383A1

## CPC

- G05B 19/4183: {characterised by data acquisition, e.g. workpiece identification}
- G05B 23/024: {Quantitative history assessment, e.g. mathematical relationships between available data; Functions therefor; Principal component analysis [PCA]; Partial least square [PLS]; Statistical classifiers, e.g. Bayesian networks, linear regression or correlation analysis; Neural networks}
- G05B 19/41865: {characterised by job scheduling, process planning, material flow}
- G05B 19/41885: {characterised by modeling, simulation of the manufacturing system}
- G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G)

## Abstract

A unit space generating device (141) which generates a unit space for use when diagnosing an operating state of a plant on the basis of a Mahalanobis distance is provided with: a sampling data acquiring unit (141A) which acquires a sampling data group comprising a plurality of state quantities of the plant, measured with a fixed period; an adoption determining unit (141C) which, on the basis of an adoption probability calculated each time the sampling data group is acquired, determines whether the sampling data group is to be adopted as a unit space generation data group serving as the basis for a unit space; a unit space generating unit (141D) which generates unit spaces on the basis of a plurality of the adopted unit space generation data groups; and an output value acquiring unit (141B) which acquires an output value of the plant corresponding to the sampling data group.

## Claims

### Claim 1

A unit space generating device that generates a unit space used in a case of diagnosing an operation state of a plant on the basis of a Mahalanobis distance, the device comprising:
a sampling data acquisition unit that acquires a sampling data group including a plurality of state quantities of the plant, which are measured for each fixed cycle;
an adoption determination unit that determines whether or not to adopt the sampling data group as a unit space generation data group, which is based on the unit space, on the basis of an adoption probability calculated each time the sampling data group is acquired;
a unit space generation unit that generates the unit space on the basis of a plurality of the adopted unit space generation data groups; and
an output value acquisition unit that acquires an output value of the plant corresponding to the sampling data group,
wherein the adoption determination unit calculates the adoption probability such that the sampling data group at a point where an absolute value of at least one of a change rate and a change amount of the acquired output value is large is likely to be adopted, and
the adoption determination unit raises the adoption probability as the absolute value of at least one of the change rate and the change amount of the acquired output value increases.

### Claim 2 (depends on 1)

The unit space generating device according to claim 1, wherein the change rate is represented by an absolute value of a second derivative of the output value.

### Claim 3 (depends on 1)

The unit space generating device according to claim 1, wherein the change amount is represented by an absolute value of a first derivative of the output value.

### Claim 4 (depends on 1)

A plant diagnosing system that diagnoses an operation state of a plant, the system comprising:
a Mahalanobis distance calculation unit that calculates a Mahalanobis distance on the basis of a state quantity of the plant acquired in a case of diagnosing the operation state of the plant; and
a plant state determination unit that determines whether or not the operation state of the plant is normal on the basis of a unit space and the Mahalanobis distance,
wherein the unit space is generated using the unit space generating device according to claim 1.

### Claim 5

A unit space generating method of generating a unit space used in a case of diagnosing an operation state of a plant on the basis of a Mahalanobis distance, the method comprising:
a sampling data acquisition step of acquiring a sampling data group of a state quantity of the plant, which is measured for each fixed cycle;
an adoption determination step of determining whether or not to adopt the sampling data group as a unit space generation data group, which is based on the unit space, on the basis of an adoption probability calculated each time the sampling data group is acquired;
a unit space generation step of generating the unit space on the basis of a plurality of the adopted unit space generation data groups; and
a step of acquiring an output value of the plant corresponding to the sampling data group,
wherein in the adoption determination step,
the adoption probability is calculated such that the sampling data group at a point where an absolute value of at least one of a change rate and a change amount of the acquired output value is large is likely to be adopted, and
the adoption probability is raised as the absolute value of at least one of the change rate and the change amount of the acquired output value increases.

### Claim 6 (depends on 5)

A plant diagnosing method of diagnosing an operation state of a plant, the method comprising:
a Mahalanobis distance calculation step of calculating a Mahalanobis distance on the basis of a state quantity of the plant acquired in a case of diagnosing the operation state of the plant; and
a plant state determination step of determining whether or not the operation state of the plant is normal on the basis of a unit space and the Mahalanobis distance,
wherein the unit space is generated using the unit space generating method according to claim 5.

### Claim 7

A program that causes a computer of a unit space generating device, which generates a unit space used in a case of diagnosing an operation state of a plant on the basis of a Mahalanobis distance, to function, the program causing the computer to execute:
a sampling data acquisition step of acquiring a sampling data group of a state quantity of the plant, which is measured for each fixed cycle;
an adoption determination step of determining whether to adopt the sampling data group as a unit space generation data group, which is based on the unit space, on the basis of an adoption probability calculated each time the sampling data group is acquired;
a unit space generation step of generating the unit space on the basis of a plurality of the adopted unit space generation data groups; and
a step of acquiring an output value of the plant corresponding to the sampling data group,
wherein in the adoption determination step,
the adoption probability is calculated such that the sampling data group at a point where an absolute value of at least one of a change rate and a change amount of the acquired output value is large is likely to be adopted, and
the adoption probability is raised as the absolute value of at least one of the change rate and the change amount of the acquired output value increases.

### Claim 8 (depends on 7)

A program that causes a computer of a plant diagnosing system which diagnoses an operation state of a plant to function, the program causing the computer to execute:
a Mahalanobis distance calculation step of calculating a Mahalanobis distance on the basis of a state quantity of the plant acquired in a case of diagnosing the operation state of the plant; and
a plant state determination step of determining whether or not the operation state of the plant is normal on the basis of a unit space and the Mahalanobis distance,
wherein the unit space is generated using the program according to claim 7.