Maintenance information device, condition sensor for use therein and method which can be carried out therewith for arriving at a decision whether or not to perform servicing or maintenance

• US 9,477,222 B2
• Filed: 10/11/2011
• Issued: 10/25/2016
• Est. Priority Date: 10/28/2010
• Status: Active Grant

• Current Assignee: EADS Deutschland GmbH (Airbus SE)
• Original Assignee: EADS Deutschland GmbH (Airbus SE)
• Inventors: Schramm, Gerrit, Schirrmann, Arnd, Zoller, Klaus
• Primary Examiner(s): Le, John H
• Application Number:
  US13/881,773
• Publication Number:
  US 20140365178A1
• Time in Patent Office: 1,841 Days
• Field of Search: 702/34, 702/179, 702/184, 702/194, 73/7, 738/659, 340/870.01, 700/286, 709/224
• US Class Current: 1/1
• CPC Class Codes: G05B 2219/32234 Maintenance planning
• CPC Class Codes: G05B 23/0208 characterized by the configuration of the monitoring system
• 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 maintenance information device and method for performing condition-based maintenance by monitoring of the condition of a technical system using a sensor. In order to permit the use of relatively simple sensors with relatively simple evaluation logics, the method and device perform decision making processes on the basis of hyperordinal signals from imperfect hyperordinal condition sensors.

Claims

1. A maintenance information device for supplying information for condition-based maintenance of a technical system, comprising:

an ordinal sensor having a sensor element configured to monitor at least one load variable or wear variable of the technical system as an indicator of a maintenance-relevant condition of the system, the sensor being further configured to supply an ordinal condition signal;

an operating-scope-detection device configured to detect a cumulated scope of the operation of the system as a value of an operating scope parameter;

an expected-value-supplying device configured to supply a degradation function which represents the expected degradation profile of the condition, which can be determined by the load variable or wear variable, as a function of the operating scope parameter;

a remaining-service-life-determining device which is configured to perform at least one of a) and b) as follows;

a) when at least one predetermined degree of degradation of the condition occurs, compare the current value reached for the operating scope parameter with the value of the operating scope parameter which is expected for this predetermined degree of degradation according to the expected degradation profile and due to the current value of the operating scope parameter, supply a recalibrated expected degradation profile of the condition plotted against the operating scope parameter; and

b) when at least one predetermined value of the operating scope parameter occurs, compare the current degree of degradation of the condition detected by the sensor with the value of the operating scope parameter which is expected according to the expected degradation profile given this degree of degradation and, due to the current degree of degradation, supply a recalibrated expected degradation profile of the condition plotted against the operating scope parameter; and

a maintenance-recommendation-generating device configured to generate a maintenance recommendation for a future planning time period on the basis of the recalibrated expected degradation profile.

2. The maintenance information device as claimed in claim 1, wherein

the maintenance-recommendation-generating device is configured to classify a current state of health of the system to be monitored into a plurality of classes.

3. The maintenance information device as claimed in claim 2, wherein

the maintenance-recommendation-generating device is configured to classify a state of health into at least two classes which are selected from a group of classes which contains at least one of the following:

a nominal operating condition,

measurable wear, but no risk of failure of the monitored system,

shortly imminent system failure, and

system failure.

4. The maintenance information device as claimed in claim 3, wherein

the remaining-service-life-determining device is configured to carry out recalibration of the expected degradation profile in the case of a transition between two classes.

5. The maintenance information device as claimed in claim 3, wherein

the expected-value-supplying device is configured to produce an expected degradation curve as a model for the degradation, from a database with at least one of empirical for the system and simulation values for the system.

6. The maintenance information device as claimed in claim 2, wherein

the remaining-service-life-determining device is configured to carry out recalibration of the expected degradation profile in the case of a transition between two classes.

7. The maintenance information device as claimed in claim 6, wherein

the expected-value-supplying device is configured to produce an expected degradation curve as a model for the degradation, from a database with at least one of empirical values for the system and simulation values for the system.

8. The maintenance information device as claimed in claim 2, wherein

the expected-value-supplying device is configured to produce an expected degradation curve as a model for the degradation, from a database with at least one of empirical for the system and simulation values for the system.

9. The maintenance information device as claimed in claim 2, wherein

the remaining-service-life-determining device is configured to determine a remaining service life distribution from accumulated degradation models, which are determined from a system database, and from the measured ordinal condition signal of the system.

10. The maintenance information device as claimed in claim 1, wherein

the expected-value-supplying device is configured to produce an expected degradation curve as a model for the degradation, from a database with at least one of empirical values for the system and simulation values for the system.

11. The maintenance information device as claimed in claim 10, wherein

the degradation profile, currently detected by the sensor, of at least one of the load variable and the wear variable, is included in the database as further empirical values by the operating scope parameter.

12. The maintenance information device as claimed in claim 1, wherein

the remaining-service-life-determining device is configured to determine a remaining service life distribution from accumulated degradation models, which are determined from a system database, and from the measured ordinal condition signal of the system.

13. The maintenance information device as claimed in claim 12, wherein

the remaining-service-life-determining device is configured to supply a hyperordinal system condition signal.

14. A method for deciding whether maintenance of a technical system is to be carried out, the method comprising:

monitoring the system using a sensor element and supplying a condition signal and a current value, present during the detection of the condition signal, of an operating scope parameter which specifies the scope of the operation of the system;

determining an expected degradation profile for the condition which represents an expected degradation of the condition by the operating scope parameter from at least one of empirical values for the system and simulation values for the system;

determining a remaining-service-life-expectation distribution from the condition signal supplied the sensor element and from the expected degradation function;

classifying the remaining service life expectation into one of a plurality of predefined classes; and

generating a maintenance recommendation on the basis of the class obtained.

15. The method as claimed in claim 14, wherein the monitoring of the system includes at least one of the following operations:

using an imperfect ordinal sensor to detect at least one of a load variable and a wear variable which specifies information about a state of health of the monitored system;

detecting at least one current value of the operating scope parameter at the time of measurement of a predetermined value of the at least one of the load variable and the wear variable; and

detecting a current value of at least one of the load variable and the wear variable when a predetermined value of the operating scope parameter occurs.

16. The method as claimed in claim 14, wherein the determining of a remaining-service-life-expectation distribution includes at least one of the following:

when at least one predetermined degree of degradation of the condition monitored by the sensor is detected, comparing the current value of the operating scope parameter reached during this detection with the value expected for this predetermined degree of degradation according to the expected degradation profile, and recalibrating the expected degradation profile by the operating scope parameter on the basis of the value of the operating scope parameter;

when at least one predetermined value of the operating scope parameter is reached, detecting the current degree of degradation then present by the sensor and comparing the current degree of degradation with the value of the operating scope parameter expected in the case of this degree of degradation according to the expected degradation profile, recalibrating the expected degradation profile based on the degree of degradation detected, and determining the remaining service life distribution on the basis of the expected degradation profile that was recalibrated.

17. The method as claimed in claim 16, wherein

the monitoring of the system includes classifying the measured condition signal into one of a plurality of classes and indication of the corresponding class;

and

the comparing of the current value of the operating scope parameter is carried out at the transition from one class to another class.

18. The method as claimed in claim 17, wherein the classifying includes classifying the measured condition signal into one of at least two classes which are selected from a group of classes which contains at least one of the following:

a nominal operating condition,

measurable wear, but no risk of failure of the monitored system,

shortly imminent system failure, and

system failure.

19. The method as claimed in claim 14, wherein the classifying of the remaining service life includes classifying the remaining service life distribution, determined when determining a remaining-service-life-expectation distribution, into one of at least two classes which are selected from a group of classes which contains at least one of the following:

a nominal operating condition,

measurable wear, but no risk of failure of the monitored system,

shortly imminent system failure, and

system failure.

20. The method as claimed in claim 14, wherein the determining an expected degradation profile includes at least one of the following operations:

interrogating a system database with empirical values or simulation values as to which degrees of degradation for the condition are to be expected at which values of the operating scope parameter; and

producing an accumulated degradation model for the system from empirical values or simulation values.