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Product Life Cycle SupportRODON contribution to the life cycleThe RODON software tool enables an effective, highly efficient and innovative engineering process based on mathematical models and methods for the synthesis and analysis of the functionality of complex technical systems. Based on a Virtual Product Model (VPM) RODON covers different analytical tasks during important phases of the entire life cycle of technical products - from design capture functions via high level system optimization and executable specifications – both supporting engineering, via reliability analyses supporting quality assurance, to diagnostics supporting both, manufacturing as well as service operations. The Virtual Product Model evolves along the phases with respect to both, granularity and functional and diagnostic details. Figure 1-4 depicts RODON’s contributions to the various phases of a product’s life cycle. RODON model of an automotive exterior electrical system with results of a Model Based Diagnostics (MBD) or Minimal Cut Set (MCS) analysis showing single points of failure or single fault diagnostic candidates respectively. RODON supports the V-Chart based development approach for systems as described below.
RODON and the V-Chart The development cycle begins at the upper left hand step with a high level vehicle specification. Depending on its nature, it already can be modeled and system level analyses can be performed. In other words, the model is an executable specification. This model or specification can be further refined at the lower level steps until one reaches the bottom where the devices have to be designed and manufactured. On all levels one can check the functionality and the compatibility of the models. Once the devices are delivered they need to be tested against the specification. This can be done with RODON’s MBD engine. It can readily help find deviations between the “as built” and “as specified” representations. As the integration process proceeds, eventually a fully integrated vehicle exists and its system functions can now be verified by RODON. The diagnostic knowledge and methods available then can be used for maintenance in the operational phase. This implies that models at various levels of abstraction can be built with RODON. Examples of this are shown with the steer-by-wire model in § 1.4.3 and the “physical level models” in the same paragraph and others. Certainly intermediate level models can be built as well. Different Operational EnvironmentsRODON can operate in a stand-alone mode for engineering and QA analysis tasks or in on-line mode to actively monitor systems in operation to detect failures and diagnose root causes. RODON is highly adaptable in terms of integration with existing trouble-detection systems in vehicles or factory equipment. RODON Applications in different phases of the Product Life CycleTypical applications of RODON in different phases of the product life cycle are: Design Capture: Schematics, for instance for electrical systems, can be generated with RODON virtually the same way as one finds in conventional E-CAD-tools. However, at the same time the circuit is designed, RODON builds a model. And a RODON model is more than design - it is a mathematical description of the functionality. This can be used for immediate analysis of the designed or modeled system. See Figure 1-7 for an example. System Optimization and Reliability: Complex and safety critical systems such as x-by-wire or fly-by-wire systems can be analyzed with respect to their failure probabilities and minimal cut sets on system level. Also they can be optimized with respect to a user definable objective function and side conditions such as upper limits of failure probabilities per system function and similarly lower boundaries of minimal cut sets. See Figure 1-8 for an example. Modeling for these analyses is generally done on a very abstract level. This is in part also due to the fact that detailed knowledge is not yet available in this early stage of a project. Executable Specification: Due to the fact that RODON models contain a declarative, however, executable description of the behaviour of its components and the entire system, they can be viewed as executable specifications. Detailed System Analyses: The following analyses are usually done on a much more detailed modeling level as compared to the one used for system optimization and reliability analysis described above. They are based on models representing the physical behavior of the components. Reliability Analyses: The failure of components and the resulting effects on the system level, and vice versa, can be systematically computed and analyzed early in the development cycle with RODON. They include but are not limited to:
Diagnosis: RODON provides systematic, scalable and in most cases industry proven diagnostic methods for both vehicle on-board diagnostics as well as manufacturing and off-board service bay diagnostics. Diagnostic knowledge for fault detection and isolation can be represented in three styles as
RODON computes these results by simulating the system in various operating modes combined with failure modes. Hereby it generates explicit information on the interplay of the product’s components and the system behavior. Especially, RODON can systematically compute symptoms or top events from root causes of a malfunction and vice versa, i.e. finds the root cause of a failure from symptoms (events). It derives reliability analyses and diagnostic knowledge from these root cause of a failure |
symptom (event) relationships.