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bok:eng:mbse:method [2020/09/09 04:40] anwlur [Survey of MBSE Methodologies] added gap to Vitech MBSE methodology 2nd edition |
bok:eng:mbse:method [2020/09/18 10:38] (current) anwlur [JPL State Analysis (SA)] |
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<WRAP center round info 60%> | <WRAP center round info 60%> | ||
- | Gaps to the 2008 survey include | + | Gaps that the below survey seeks to address to the 2008 survey include |
* 2010 revision to Harmony/SE | * 2010 revision to Harmony/SE | ||
- | * 2nd edition for Vitech MBSE Methodology (released 2011) | + | * 2nd edition for Vitech MBSE Methodology (released 2011) |
- | * Inclusion of SYSMOD | + | * 2012 release of JPL SA |
+ | * inclusion of SYSMOD | ||
+ | * inclusion of Functional Architecture for Systems | ||
</WRAP> | </WRAP> | ||
- | |||
===== Ontology ===== | ===== Ontology ===== | ||
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==== Vitech MBSE Methodology ==== | ==== Vitech MBSE Methodology ==== | ||
+ | The source for the Vitech MBSE Methodology is D. Long & Z, Scott "A Primer for Model-Based System Engineering", Vitech Corporation, 2nd edition (2011). This is available for download [[http://www.vitechcorp.com/resources/mbse.shtml|here]]. | ||
+ | |||
+ | === Objectives === | ||
+ | |||
+ | The design space includes three systems (a simplification of J. Martin's seven [[bok:eng:sys:intro#process|systems]]) | ||
+ | * Designing System | ||
+ | * System Under Design - solves a problem | ||
+ | * Context System - users of the system, environment, other interacting systems | ||
+ | |||
+ | === Development Activities === | ||
+ | |||
+ | Vitech Methodology describes main activities (Requirement Analysis, Functional Behavior Analysis, Architectural Synthesis) addressing, respectively, the domains of Requirements, Behavior, Architecture, Verification and Validation. | ||
+ | |||
+ | - Requirements Analysis | ||
+ | - Explore stakeholder needs creating a statement of system functionality | ||
+ | - Increase granularity of system behavior (that realizes need) and therefore increase specificity of requirements | ||
+ | - Functional Behavior Analysis | ||
+ | - Addresses (a) what the system must do in order to answer customer's need and (b) how well the system must perform these functions (i.e. measure of effectiveness) | ||
+ | - Construct logical model | ||
+ | - Architectural Synthesis | ||
+ | - Development of the physical model | ||
+ | - Allocating logical model to the physical model | ||
+ | - Trace requirements (through the logical mode) to the physical model | ||
+ | - Validation & Verification | ||
==== JPL State Analysis (SA) ==== | ==== JPL State Analysis (SA) ==== | ||
+ | |||
+ | Sources for this methodology include | ||
+ | |||
+ | * D. Wagner, "An Ontology for State Analysis: Formalizing the Mapping to SysML", IEEE (2012). Accessed on September 10th, 2020 [[http://www.omgsysml.org/State_Analysis_Ontology%20_in_SysML.pdf|here]]. | ||
+ | * D. Wagner, "An Ontology for State Analysis: Formalizing the Mapping to SysML", Presentation to IEEE Aerospace Conference (March 2012). Accessed on September 10th, 2020 [[https://trs.jpl.nasa.gov/bitstream/handle/2014/42601/12-0881.pdf|here]]. | ||
+ | |||
+ | JPL State Analysis... | ||
+ | |||
+ | * provides a methodology to design complex control systems | ||
+ | * Typical architecture is as below | ||
+ | |||
+ | {{ :bok:eng:mbse:method:jpl_sa1.png?500 |}} | ||
+ | |||
+ | * Mission Planning & Execution supplies Control Goals to State Control | ||
+ | * Mission Planning & Execution supplies Knowledge Goals to State Estimation | ||
+ | * State Estimation supplies State Functions :?: to State Knowledge | ||
+ | * State Knowledge supplies State Values to State Control | ||
+ | * Models bridges State Estimation, Knowledge and Control | ||
+ | * State Control supplies Commands to Hardware Adapter | ||
+ | * Sense (sensors) and Act (actuators) are ports to Hardware Adapter. Hardware Adapter is child to System Under Control | ||
+ | * Actuator creates changes which influences Sensors | ||
+ | * Hardware Adapter supplies Measurements & Commands to State Estimation | ||
+ | |||
+ | === Rationale === | ||
+ | |||
+ | * As system complexity grows it is not possible to manage a system based on subsystem-level functional decomposition, the web of interactions are too great | ||
+ | * There is a gap between requirements on SW specified by system engineers and the implementation of these requirements by software engineers, leaving open the possibility of misinterpretation of system engineer's intent | ||
+ | |||
+ | === Objectives === | ||
+ | |||
+ | * Facilitates system engineers to precisely express design intent in a tool that actively ensures consistency | ||
+ | * Clear distinction between Control System and System Under Control | ||
+ | * Provide a methodology for | ||
+ | * Discovering and documenting states of a system | ||
+ | * Modeling behavior of state variables and relationships between them | ||
+ | * Capturing mission objectives in detailed scenarios motivated by operator intent | ||
+ | * Keep track of system constraints and operating rules | ||
+ | * Describing methods by which objectives will be achieved | ||
+ | |||
+ | === Development Activities === | ||
+ | |||
+ | - The foundation of the JPL SA methodology is the control system and the //system under control// are explicitly different. This separation is formalized in an //ontology// which is written in OWL2. JPL used [[https://protege.stanford.edu/|Protege]] as the editing environment. | ||
+ | - This ontology is mapped to SysML artifacts using Query/View/Transformation (QVT), a model-to-model transformation standard by OMG. | ||
+ | - A context diagram (block diagram) includes //Analysis Context// with parts //System Under Control// and //Control System// | ||
+ | - In a state effects diagram (=internal block diagram) map the relationship between different state variables contained within the context. Use //affects// and //affectedBy// relationships. | ||
+ | - Define mathematical relationships between State Variables with parametric diagrams | ||
+ | - Control System is designed. A State Variable has only 1 //Controller// and (may) have only one //Estimator// | ||
+ | - The //HardwareAdapter// is modeled to be an interface between the Control System and System Under Control. Measurements flow from System Under Control to Control System, Controls flow the other way. | ||
+ | - Goals are elaborated as (typically) stereotyped use cases whilst the temporal aspect of goals is defined as constraints and analyzed in parametric diagrams. | ||
==== Object-Process Methodology (OPM) ==== | ==== Object-Process Methodology (OPM) ==== | ||
==== SYSMOD ==== | ==== SYSMOD ==== | ||
+ | |||
+ | ==== Funcational Architecture Methodology ==== | ||
+ | |||