Articles

The provision of integrated modeling, simulation and optimization tools to effectively support all stages of aircraft design remains a critical challenge in the aerospace industry. While several breakthroughs have been achieved in this area, costly iterations are still often necessary to successfully design, develop, integrate, validate and verify the components and subsystems of modern aircraft. The high level of system integration that is characteristic of new aircraft designs is dramatically increasing the complexity of both design and verification – in particular for fault condition analysis and the implementation of defect-free software (Figure 1).

Simultaneously, the multi-physics interactions between structural, electrical, thermal, and hydraulic components have become more significant as the systems become increasingly interconnected (e.g. the interaction among thermal load due to increased cabin electrical power usage, an electrically-powered environmental control system, and electrically powered flight control actuation).

This complex interaction between subsystems is difficult to capture through a traditional “document-based systems engineering” requirements-driven design approach, which often prevents the discovery of novel subsystem architectures that may achieve multi-objective optimization across subsystems. This occurs due to the “one-way” hierarchical requirements derivation from the whole aircraft down to individual components, and leads to over-costing and suboptimal solutions that often require substantial rework to address performance shortfalls where top-level decisions cannot be modified. New methodologies and tools are therefore required to enable better coordination between different design disciplines, so that appropriate requirements are specified at different design phases, and design trades and potential problems are identified before physical prototypes are built and tested through expensive test campaigns.

Figure 1. Increase in electrical power and software complexity on aircraft.

In order to address such needs, Model-Based Systems Engineering (MBSE) has emerged as an alternative design approach. MBSE can be defined as the “formalized application of modelling to support system requirements, design, analysis, verification and validation activities, beginning in the conceptual design phase and continuing throughout development and later life cycle phases.” Despite the significant advances in modeling, simulation, design and virtual testing that have been achieved, there is still a lack of integrated frameworks enabling multi-physics modeling and simulation, multi-objective optimization, model-based design of algorithms, and virtual testing, which can support all of the different design and development phases. It has been demonstrated that a lack of integration in the toolset can be a major cause for delays in the case of complex new designs.

A new integrated modeling, simulation and optimization framework is therefore required by Aerospace industry to incorporate effectively MBSE in all stages of aircraft design and development. Standardized multi-domain modeling languages (e.g. Modelica) and interfacing with other common tools used in Aerospace industry, e.g. via the Functional Mockup Interface (FMI), are key aspects to reach those goals.

Goals

The aim of the MISSION (Modelling and Simulation Tools for Systems Integration on Aircraft) project is to develop and demonstrate an integrated modeling, simulation, design and optimization framework based on MBSE and oriented to the Aerospace industry. This framework will holistically support the entire design, development and validation process of an aircraft, starting from conceptual aircraft-level design, toward capture of key requirements, system design, integration, validation and verification. In the development of this tool, the following objectives are pursued:

Objective 1: Improve integrated design capabilities at aircraft- and system-level through integrated multi-physics modelling and multi-objective optimization, and to trade multiple design metrics including emissions (CO2, NOx), fuel burn, weight, and cost.

Objective 2: Achieve significant reductions in development time, cost and rework throughout the design, development and validation process through the extensive use of model-based-design techniques for controls and algorithms, and advanced virtual testing capabilities.

Objective 3: Support technology integration and demonstration within Clean Sky 2 through a common, open and neutral environment for integration of various technologies developed in ITD Systems.

Objective 4: Achieve wide dissemination of the developed framework to strengthen its exploitation plan. The MISSION project will regularly seek feedback and commitment from groups of stakeholders including ITD partners, scientific aerospace and technological communities/academia, regulation and standardization bodies, as well as, industrial end-users.

Overview of MISSION Platform

The platform envisioned in MISSION project is depicted in Figure 2. It is composed of the following elements:

An integrated modeling and simulation environment: A common, neutral and open environment based on the Modelica multi-domain modeling language containing the platforms and common tools of the MISSION framework.

An aircraft-level optimization platform: A platform for computer-aided design of aircraft architecture, enabling trade-offs of design metrics from a multi-objective perspective, including metrics such as CO2, NOX emissions, fuel consumption, weight, and cost.

System-level optimization platforms: Dedicated platforms for system-level design and optimization of electrical architecture, thermal architecture, landing gear, actuation systems, wings and cockpit. It will support integration of technologies being developed in Clean Sky 2.

Model-based-design tools for control and prognostics & health management algorithms: Model-based design tools for systems controls and health monitoring algorithms supporting “robust design and strong verification” of safety critical systems.

Virtual testing platforms: Platforms enabling validation and verification of designs at multiple levels of abstraction, including partial virtual certification of aircraft components, including computation and communication architectures. The platforms will support PC-based testing in early development phases and lab-based real-time testing of simulated control units and real control units.