INCREMENT a tool to enhance concurrent design activities Ivo Ferreira ivotomar@gmail.com Instituto Superior Técnico - Lisbon - Portugal
Outline Context Conceptual design phase of space systems Current design process Design modelling methodologies INCREMENT Movie with example Earth observation satellite Current limitations Monitoring interaction Dynamic design structure matrix 2
% of cost Conceptual Design Phase Initial design stage First high-level design choices Definition of around 70% of the total cost of the project 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Committed Realized Conceptual design Detailed design Setting up the supply chain Production Maintenance & Service [ddapted from (Nevins 1989; Hartley 1992)] Impact even higher when dealing with complex systems such as space systems - Many disciplines - Different groups have different views - Interactions between disciplines (dynamic during design) - TotalSystem > Σ Subsystems 3
Design process - Concurrent Engineering Focusing all activities related to the development of a product in the early stages of product design Concurrent Engineering is based on three key elements: Multidisciplinary team Process Software infrastructure [Source: http://www.esa.int] 4
Design Modelling Methologies (1/2) Used to define the attributes of the system Different levels of abstraction: lexical, graphic or a combination of both SysML Specifically tailored for complex engineering systems May include hardware, software, information, personnel, procedures, and facilities Structure, ehaviour, Requirements Model ased System Engineering [Source: www.omgsysml.org/] 5
Design Modelling Methologies (2/2) OPM Object Process Methodology Every system can be represented by 3 entities n object is a thing that exists or has the potential of existence, physically or mentally process is a pattern of transformation that an object undergoes state is a situation an object can be at 6
Current limitations Design process No clear process defining how to get from the initial high level requirements to a baseline solution in a concurrent environment Perceived with less performance than common Waterfall or V-Models No real-time perspective on the evolution of the system Design modelling methodologies MSE very complex to be used by designers (tailored for system architects) Subsystem level tools are completely detached from modelling methodologies 7
Monitoring the interaction during conceptual design Structure (Relationships) Values (Models) Design History 8
Design Structure Matrix (DSM) Series Parallel Coupled X X X These three types of dependencies can be easily depicted in a Design Structure Matrix In a Concurrent Engineering environment it can be useful to have: a static view over the component based architecture a time parameter based view of the parameters that determine the design 9
Dynamic Design Structure Matrix (DSM) Realtime update of all the design changes with the use of additional dimension (e.g. color) to give information on: Status of the relationship (if parameter relationship between disciplines was accepted and/or there is a model describing the behavior of the parameter) Parameter assignments (if there is a fixed value, a range of possible values, there is a list of possible values) Quality of the assignments (on whether the value is final and based on a design decision) Impact of each parameter on the downstream discipline Completion state (requiring reiteration, completed, problem) 10
INCREMENT INtegrated Concurrent Realtime EnvironMENT Integrates subsystem level models with the design modelling needs llows the definition and real-time monitoring of the different disciplines, participants, design items, and design parameters Provides the realtime visualisation of the evolution of the design process Keeps track of all design changes and allows traceability Enables a knowledge management strategy Generates design possibilities based on current definitions of the system MOVIE (example Earth observation satellite) 11