METHOD AND SYSTEM FOR DETERMINING RELIABILITY PARAMETERS OF A TECHNICAL INSTALLATION

• US 20100125746A1
• Filed: 02/08/2008
• Published: 05/20/2010
• Est. Priority Date: 02/08/2007
• Status: Abandoned Application

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Herrmann, Jürgen, Konnov, Alexei
• Application Number:
  US12/526,340
• Publication Number:
  US 20100125746A1
• Time in Patent Office: Days
• US Class Current: 714/1
• CPC Class Codes: G05B 19/4184 characterised by fault tolerance, reliability of production system
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A method calculating reliability parameters of a technical installation is provided. The reliability parameters are calculated using a modified Markov minimum cut method in which probabilities of a plurality of components failing on account of a common cause and the property of a component or subassembly with self-diagnosis are concomitantly included in the calculation of the reliability parameters. The input parameters for the calculation model are determined from messages and/or subsystems in the technical installation or from the overall installation. The failure and repair rates calculated may be used to predict the reliability, availability, maintainability and safety of the technical installation.

Claims

1-11. -11. (canceled)

12. A method for determining reliability parameters of a technical installation, comprising:

forming a reliability model by establishing a logical structure of a subsystem of the technical installation using a top-down approach;

determining, within the logical structure, a plurality of relevant minimal steps up to a maximum of a third order;

determining the plurality of input parameters for all of the plurality of individual components of a cut and the corresponding rates are determined within each cut using a confidence interval;

determining a state transition matrix for each minimum cut using the plurality of input parameters;

creating a system of differential equations using the state transition matrix, from which a probability of an occurrence of the each minimum cut is determined; and

determining the failure probability, the failure rate and repair rate of the subsystem by adding all probabilities for the occurrence of a minimum cut,

wherein a plurality of input parameters for a reliability calculation model are determined from a message and/or data from a plurality of individual components, a plurality of subsystems of the technical installation, or the entire technical installation,

wherein the plurality of input parameters comprise at least the following parameters, failure rates of the plurality of individual components or subsystems, repair rates of the plurality of individual components or subsystems, failure rates due to a common cause, failure rates of components with self-diagnosis in which a failure has been detected, and failure rates of components with self-diagnoses in which the failure has not been detected, and

wherein the reliability parameters are calculated using a Markov minimum cut method.

13. The method as claimed in claim 12,

wherein the reliability parameters are calculated during an operation of the technical installation, and

wherein a message and/or data from a plurality of individual components, the plurality of subsystems of the technical installation or the entire installation are determined online.

14. The method as claimed in claim 12, wherein the message and/or the data from the plurality of individual components, the plurality of subsystems of the technical installation and the entire installation match field values which are obtained in a process-oriented manner from a control system of the technical installation or in the field.

15. The method as claimed in claim 12, wherein the plurality of input parameters are determined from default data from a database for the plurality of individual components of the technical installation.

16. The method as claimed in claim 12,

wherein the theoretically calculated reliability parameters calculated using the reliability calculation model are compared with previously determined field values, and

wherein the theoretically calculated reliability parameters are output if the theoretically calculated reliability parameters and the field values are within a specified precision interval.

17. The method as claimed in claim 12, further comprising:

comparing the theoretically calculated reliability parameters using the reliability calculation model with a previously determined field values;

making an adjustment of the reliability calculation model if the theoretically calculated reliability parameters and the field values are outside of the specified precision interval; and

calculating the reliability parameters with a subsequent comparison with field values until the theoretically calculated values and the field values are within a specified precision interval.

18. The method as claimed in claim 17, wherein the reliability calculation model is adjusted by changing the rates for detecting the failure probabilities due to a common cause and diagnostic coverage.

19. A system for determining the reliability parameters for a technical installation, comprising;

a first module for communication with databases and additional systems and a plurality of components of the technical installation for reading out a message and/or data from the technical installation;

a second module for determining a plurality of input parameters for a reliability calculation model from the read-out message and/or data, wherein the input parameters include at least failure rates of individual components or subsystems, repair rates of individual components or subsystems, failure rates due to a common cause, failure rates of components with self-diagnosis in which the failure has been detected, and failure rates of components with self-diagnosis in which the failure has not been detected;

a calculating module in which reliability parameters for an individual component, a subsystem or an entire system of the technical installation are calculated using the plurality of input parameters and a Markov minimum cut method which uses failure probabilities due to a common cause and diagnostic coverage,

wherein the Markov minimum cut method comprises;

forming a reliability model by establishing a logical structure of a subsystem of the technical installation using a top-down approach,

determining, within the logical structure of the technical installation, a relevant minimal step up to a maximum of a third order,

determining the plurality of input parameters for all of the plurality of components of the cut and the corresponding rates are determined within each cut using a confidence interval,

determining a state transition matrix for each minimum cut using the plurality of input parameters,

creating a system of differential equations using the state transition matrix, from which a probability of an occurrence of the individual minimum cuts is determined,

determining a failure probability, a failure rate and a repair rate of the subsystem by adding all probabilities for the occurrence of a minimum cut, and

wherein an output unit is used as a graphic user interface for depicting the calculated reliability parameters.

20. The system as claimed in claim 19, further comprising a first database in which empirical values of the plurality of input parameters are stored for the plurality of individual components, a plurality of subsystems and the entire system, and at least one additional database in which field values of the plurality of input parameters are stored for the plurality of individual components, the plurality of subsystems and the entire system, and

wherein the field values are an installation data and error messages from the technical installation.

21. The system as claimed in claim 19, wherein the technical installation is a control installation and a plurality of additional systems are a process control and information system, a planning system, a diagnostic system and/or an automation system.

22. The system as claimed in claim 19, wherein the system performs a method for determining reliability parameters of a technical installation, comprising:

forming a reliability model by establishing a logical structure of a subsystem of the technical installation using a top-down approach,

determining, within the logical structure of the technical installation, a relevant minimal step up to a maximum of a third order,

determining the plurality of input parameters for all of the plurality of components of the cut and the corresponding rates are determined within each cut using a confidence interval,

determining a state transition matrix for each minimum cut using the plurality of input parameters,

creating a system of differential equations using the state transition matrix, from which a probability of an occurrence of the individual minimum cuts is determined,

determining a failure probability, a failure rate and a repair rate of the subsystem by adding all probabilities for the occurrence of a minimum cut.