Adaptive output feedback control of aircraft flexible modes

The application of adaptive output feedback augmentative control to the flexible aircraft problem is presented. Experimental validation of control scheme was carried out using a three disk torsional pendulum. In the reference model adaptive control scheme, the rigid aircraft reference model and neural network adaptation is used to control structural flexible modes and compensate for the effects unmodeled dynamics and parametric variations of a classical high order large passenger aircraft. The attenuation of specific low and high frequency flexible mode depending on linear controller design specifications and adaptation parameters were observed. The effectiveness of the approach was seen in flexibility control of the high dimensional, nonminimum phase, nonlinear aircraft model with parametric uncertainties of wind and unmodeled dynamics of actuators and sensors

Simulation product fidelity: a qualitative & quantitative system engineering approach

La modélisation informatique et la simulation sont des activités de plus en plus répandues lors de la conception de systèmes complexes et critiques tels que ceux embarqués dans les avions. Une proposition pour la conception et réalisation d'abstractions compatibles avec les objectifs de simulation est présentée basés sur la théorie de l'informatique, le contrôle et le système des concepts d'ingénierie. Il adresse deux problèmes fondamentaux de fidélité dans la simulation, c'est-à-dire, pour une spécification du système et quelques propriétés d'intérêt, comment extraire des abstractions pour définir une architecture de produit de simulation et jusqu'où quel point le comportement du modèle de simulation représente la spécification du système. Une notion générale de cette fidélité de la simulation, tant architecturale et comportementale, est expliquée dans les notions du cadre expérimental et discuté dans le contexte des abstractions de modélisation et des relations d'inclusion. Une approche semi-formelle basée sur l'ontologie pour construire et définir l'architecture de produit de simulation est proposée et démontrée sur une étude d'échelle industrielle. Une approche formelle basée sur le jeu théorique et méthode formelle est proposée pour différentes classes de modèles des systèmes et des simulations avec un développement d'outils de prototype et cas des études. Les problèmes dans la recherche et implémentation de ce cadre de fidélité sont discutées particulièrement dans un contexte industriel.In using Modeling and Simulation for the system Verification & Validation activities, often the difficulty is finding and implementing consistent abstractions to model the system being simulated with respect to the simulation requirements. A proposition for the unified design and implementation of modeling abstractions consistent with the simulation objectives based on the computer science, control and system engineering concepts is presented. It addresses two fundamental problems of fidelity in simulation, namely, for a given system specification and some properties of interest, how to extract modeling abstractions to define a simulation product architecture and how far does the behaviour of the simulation model represents the system specification. A general notion of this simulation fidelity, both architectural and behavioural, in system verification and validation is explained in the established notions of the experimental frame and discussed in the context of modeling abstractions and inclusion relations. A semi-formal ontology based domain model approach to build and define the simulation product architecture is proposed with a real industrial scale study. A formal approach based on game theoretic quantitative system refinement notions is proposed for different class of system and simulation models with a prototype tool development and case studies. Challenges in research and implementation of this formal and semi-formal fidelity framework especially in an industrial context are discussed

A modelling framework to support power architecture trade-off studies for More-Electric Aircraft

Abstract This work presents a modelling framework to enable comparison and trade-off study of different aircraft system architectures. The framework integrates a computational module to select feasible architectures with a modelling platform that simulates the power generation, distribution and fuel consumption of the aircraft as well as system-level models for the system being evaluated. Its capabilities are demonstrated for the case of the electrification of the primary flight control system (PFCS) using different electric technologies (EHA, EMA) and different levels of electrification ranging from the conventional hydraulic to the all-electric. The performances of different architectures are analysed with respect to the change in the mechanical power extracted from the engine, the weight and the fuel burn of the aircraft. The framework demonstrates the capability of evaluating multiple, different, system architectures in a way that is scalable for different systems or different aircraft. It supports a designer evaluating the aircraft-level impact of their design choice at system-level, and it can aid in assessing technology options early in the design process

Fidélité de produit de simulation : un approche d'ingénierie de système qualitatif et quantitatif

In using Modeling and Simulation for the system Verification & Validation activities, often the difficulty is finding and implementing consistent abstractions to model the system being simulated with respect to the simulation requirements. A proposition for the unified design and implementation of modeling abstractions consistent with the simulation objectives based on the computer science, control and system engineering concepts is presented. It addresses two fundamental problems of fidelity in simulation, namely, for a given system specification and some properties of interest, how to extract modeling abstractions to define a simulation product architecture and how far does the behaviour of the simulation model represents the system specification. A general notion of this simulation fidelity, both architectural and behavioural, in system verification and validation is explained in the established notions of the experimental frame and discussed in the context of modeling abstractions and inclusion relations. A semi-formal ontology based domain model approach to build and define the simulation product architecture is proposed with a real industrial scale study. A formal approach based on game theoretic quantitative system refinement notions is proposed for different class of system and simulation models with a prototype tool development and case studies. Challenges in research and implementation of this formal and semi-formal fidelity framework especially in an industrial context are discussed.La modélisation informatique et la simulation sont des activités de plus en plus répandues lors de la conception de systèmes complexes et critiques tels que ceux embarqués dans les avions. Une proposition pour la conception et réalisation d'abstractions compatibles avec les objectifs de simulation est présentée basés sur la théorie de l'informatique, le contrôle et le système des concepts d'ingénierie. Il adresse deux problèmes fondamentaux de fidélité dans la simulation, c'est-à-dire, pour une spécification du système et quelques propriétés d'intérêt, comment extraire des abstractions pour définir une architecture de produit de simulation et jusqu'où quel point le comportement du modèle de simulation représente la spécification du système. Une notion générale de cette fidélité de la simulation, tant architecturale et comportementale, est expliquée dans les notions du cadre expérimental et discuté dans le contexte des abstractions de modélisation et des relations d'inclusion. Une approche semi-formelle basée sur l'ontologie pour construire et définir l'architecture de produit de simulation est proposée et démontrée sur une étude d'échelle industrielle. Une approche formelle basée sur le jeu théorique et méthode formelle est proposée pour différentes classes de modèles des systèmes et des simulations avec un développement d'outils de prototype et cas des études. Les problèmes dans la recherche et implémentation de ce cadre de fidélité sont discutées particulièrement dans un contexte industriel

Codage de CDEVS et de PDEVS en réseau de Petri temporisé

National audienceThis paper presents an encoding of CDEVS (Clas-sic Discrete-EVent Specification) and PDEVS (Parallel Discrete-EVent Specification) semantics in TPN (Timed Petri Nets) with priorities and data handling. This encoding is a formal specification of the execution semantics for our simulation tool. From a Timed Petri Net based model resulting from an automatic transformation of a DEVS model designed in ProDEVS, we perform an exhaustive exploration of the model. We show how to check formal verification simulation properties related to the correctness of the model : is it well built and legitimate for all its potential uses ? Will be properly executed by the simulator.Cet article présente un codage des sémantiques CDEVS (Classic Discrete-EVent Specification) et PDEVS (Parallel Discrete-EVent Specification) en TPN (réseaux de Petri temporisés-Timed PetriNet) avec priorités et gestion des données. Ce codage constitue une spécification formelle de la sémantique d'exécution des modèles CDEVS et PDEVS pour notre outil de simulation ProDEVS [1]. A partir d'un modèlè a base de réseau de Petri résultant d'une transformation automatique d'un modèle DEVS saisi dans ProDEVS, nous exécutons une exploration exhaustive du modèle. Nous montrons comment faire une vérification formelle de propriétés de simulation liéesliées`liéesà la correction du modèle : est-il bien construit et légitime pour toutes seséventuelles ses´seséventuelles utilisations ? Sera-t-il correctement exécuté par le simulateur

Codage de CDEVS et de PDEVS en réseau de Petri temporisé

National audienceThis paper presents an encoding of CDEVS (Clas-sic Discrete-EVent Specification) and PDEVS (Parallel Discrete-EVent Specification) semantics in TPN (Timed Petri Nets) with priorities and data handling. This encoding is a formal specification of the execution semantics for our simulation tool. From a Timed Petri Net based model resulting from an automatic transformation of a DEVS model designed in ProDEVS, we perform an exhaustive exploration of the model. We show how to check formal verification simulation properties related to the correctness of the model : is it well built and legitimate for all its potential uses ? Will be properly executed by the simulator.Cet article présente un codage des sémantiques CDEVS (Classic Discrete-EVent Specification) et PDEVS (Parallel Discrete-EVent Specification) en TPN (réseaux de Petri temporisés-Timed PetriNet) avec priorités et gestion des données. Ce codage constitue une spécification formelle de la sémantique d'exécution des modèles CDEVS et PDEVS pour notre outil de simulation ProDEVS [1]. A partir d'un modèlè a base de réseau de Petri résultant d'une transformation automatique d'un modèle DEVS saisi dans ProDEVS, nous exécutons une exploration exhaustive du modèle. Nous montrons comment faire une vérification formelle de propriétés de simulation liéesliées`liéesà la correction du modèle : est-il bien construit et légitime pour toutes seséventuelles ses´seséventuelles utilisations ? Sera-t-il correctement exécuté par le simulateur

Towards an Ontology-Driven Framework for Simulation Model Development

International audienceAn ontology driven domain model approach for improving the fidelity of the simulation by developing models through the inclusion of simulation objectives for the system Verification & Validation activities (V&V) is presented. The system V&V by simulation ontology used to build this domain model is briefly outlined in the system teleological framework of Structure, Behavior, Function, Interface and Operation. The concept of operating mode is proposed and discussed with an example. The ontology approach is demonstrated with an aircraft nacelle anti-ice system presented in the experimental frame formalism. An example of using the inference and query capabilities of the domain model approach to identify and justify abstractions consistent with the test scenarios is illustrated with a failure mode case study for this application case. The relationship with formal behavioral approach through operating modes is briefly discussed at the end where some theoretical results on the behavioral compatibility of the experimental frame components with interface simulation distances are briefly presented. The paper concludes with a discussion on the benefits of this approach from an industrial perspective along with an overview of the challenges ahead and the future work

Simulation Fidelity Distance: A Game-Theoretic Framework

International audienceThe paper addresses one of the fundamental questions in using simulation as a means for system verification and validation, namely, how far the simulation model represents the real system according to the given test objective. Extending studies on quantitative approaches in system refinement based on two player games to the field of system simulation, distance notions for simulation fidelity are proposed. This fidelity distance could be quantified through alternating simulation games between the system model and the simulation model. This coverage metric initially proposed in literature, is still an absolute distance measure and inadequate for the purpose of determining the fitness of a model for an intended use, since a game relation is established only between the simulation model i.e. implementation and system model i.e. specification. In addition, all strategies of the players must be explored to quantify this error not only globally but also with respect to the given test scenario. In this paper, these games between two untimed transition systems are modeled as DEVS in the ProDEVS tool and a quantitative reachability graph is generated using the TINA tool to explore all such player strategies in the game. Further, a relative-weighted fidelity distance metric to account for given test objectives is proposed which penalize cheats on expected simulation model behavior more than the other behavior. This quantitative reachability graph is analyzed for consistency conditions, player strategies, counter examples, distribution and evolution of cheats to gain further insight into the simulation model behavior with respect to the system model and test objectives. These game notions are discussed in the context of derivability of experimental frame formalism, where a global test scenario is proposed and then consistently refined with respect to the model development cycle. Extending this quantitative approach to timed systems and interface automata is briefly discussed

A META-MODEL FOR CONSISTENT & AUTOMATIC SIMULATION MODEL SELECTION

International audienceA meta-model of modeling abstractions is presented and discussed in the context of using simulation as a means for system verification and validation activities. Extending the classical results of presenting modeling as a relevance reasoning problem, abstractions are classified to build an ontology based on the concepts of teleological modeling and relevance reasoning. The domain model is built in the standard ontology tool of Protégé to exploit the reasoning and inference capabilities to build a model abstraction library. Lattice structures of model instances are formed and a recursive algorithm is implemented as an activity diagram in SysML for automated and consistent model selection. The approach is presented with a battery model example from the literature. Challenges and future work in implementation of such a semi-formal approach in model selection is briefly presented in the context of improving fidelity of simulation in the industry

A MULTIMODAL APPROACH TO SIMULATION FIDELITY

International audienceA process oriented view of a multimodal approach to simulation fidelity is discussed in the context of system verification and validation in industry. An overview of classical simulation product development is given and the problem of developing models through the inclusion of simulation objectives is presented in terms of this process. A multi modal approach for improving the syntactic fidelity of simulation by using meta-modeling techniques and semantic web principles is presented in an operational context. The domain model is briefly presented and a concept of operating mode is proposed in the model teleological framework of Structure, Behavior, Function and Interface. The relation with the study of formal techniques on semantic or behavioral fidelity is briefly discussed along with an overview on the challenges ahead and future work