Failure Modes and Effects Analysis has long been a way to predict the consequences of failures in complex systems. FMEA has been a required part of many aerospace and military projects for many years. A number of support tools have been developed to aid in the time-consuming process of performing FMEA's. These tools generally collected data, kept it organized and produced reports according to Mil Stds. But the process of identifying the failure characteristics of individual components and determining the effects of those failures as they propagate across the systems in which they are embedded has been mainly a manual and expensive process. Powerful workstations and modern mathematical techniques are now making it possible to automate FMEA and make it a routine and affordable part of the engineering design process. This allows higher quality products to be produced faster, cheaper and more competitively. RODON is at the forefront of the new modeling and diagnosis technology that is allowing this to happen.


1. FMEA Features of RODON

* Propagates defined component faults across the entire system
* Functions for all types of systems including electrical, hydraulic, mechanic, pneumatic, thermal etc. and any combination thereof, e.g. it propagates the effect of an electrical fault into the ABS hydraulic system. Likewise it propagates the effect of an hydraulic fault into the ABS mechanical system.
* Functions for both single and multiple faults
* Allows correct quantitative assessment of a fault through the use of quantitative behavior models.
* Electrical or systems data can be imported directly from several existing EDA tools.
* Behavior of integrated Electronic Control Units (ECU's) and their faults can be taken into account as well
* ECU behavior can be directly imported via RODON's Statemate and MatrixX interfaces. Interfaces can be adapted to other modeling systems at customers request (Easy 5 and others)

2. The Process of Creating FMEA Models

* RODON model is generated including the nominal behavior and all component level fault modes
* Run RODON permutation with all intended and fault modes, creating a Simulation Table
* Save Simulation Table in Data Base (done automatically)
* Apply data base report generator to extract needed information

3. Benefits of Using RODON and Model-Based Diagnosis for FMEA

* Provides complete quantitative failure propagation across the entire system. User can define system boundaries.
* RODON models can be generated automatically from many previously-developed models minimizing the manual interaction/effort required
* Entire process can be fully automated
* Interface to traditional FMEA tools (reports) possible
* Same models can be used for Sneak Circuit Analysis and diagnostic purposes (model once, use often!)
* Same models can be used to identify and correct design flaws using rodon's model-based diagnoser at the design stage
* Same model can be used for worst case design analyses.
* Same Simulation Table can be used for FMEA, Diagnostic Table generation and SCA

The use of RODON and its Model-Based Reasoning capabilities can significantly reduce the cost and time associated with advance determination of the effects of component failures. First of all, designs can be modified to be failure-tolerant or fail-operational. And very importantly, the failure signatures of systems can be determined at design time such that when a product reaches the field, diagnostic procedures can already be prepared to identify and deal with them.

RODON represents leading-edge technology that brings to bear the ability to automate and improve many parts of the design and field diagnosis process. Integration of this technology into existing design processes in a methodical way can result in cost savings and improved product affordability.

Bill Lokken
November 1996

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