Model Driven Systems Engineering: Linking the Vee Tim Tritsch Vitech Corporation Janice Magill - NAVAIR James Newbury NAVAIR NDIA Systems Engineering Conference 24 October 2006
Topics The Vee chart Review Model Driven Systems Engineering Overview The Advanced Arresting Gear Program AAG System Model Development AAG Test Program Description of Verification Method Structure Relating Requirements to Verification Methods Summary and Conclusions 2
Forsberg and Mooz Vee Provides basic map of a system development cycle Implies each phase of design definition has associated integration and qualification activities Principles adopted in DoD acquisition guidelines and many ACAT programs ANSI/EIA- 632 (Processes for Engineering a System) Defense acquisition s Integrated Defense Acquisition, Technology and Logistics Life Cycle Management Framework 3
Requirements Development and Qualification Has been extended to include phased development strategies. 4
Model Driven Systems Engineering Complete System Definition Capture in System Model Concept of Operations System requirements System behavior System structure Component interaction (I/O) Verification, Validation, and Qualification tasks and methods Relevant relationships between all the above Consistency in documentation Multiple views of the System (Textural and/or Graphical) 5
Advanced Arresting Gear Environment Washington 6
Challenges of an Aircraft Carrier A typical airport has a runway over a mile, an aircraft carrier has less than 800 feet. On a carrier, the runway moves with the waves. On a carrier, the hot, wet, salty environment is destined to corrode any equipment. On a carrier, there are stringent equipment requirements Space limitations Rigorous shock and vibration standards Strict electromagnetic interference and compatibility requirements On a carrier, equipment is repaired and maintained by 19 year olds working 12 hour shifts. 7
Advance Arresting Gear Naval Air System Command (NAVAIR) and General Atomics (GA) have taken the challenge to develop a new arresting system that will take aircraft carriers into the 21 st century The AAG program Has completed a technology demonstration phase Was designated ACAT II at MS B in October 2004 Is currently in System Development and Demonstration Has Low Rate Initial Production slated for October 2009 The team is jointly applying a Model Based Approach to manage the Advance Arresting Gear system definition. 8
AAG System Model Development NAVAIR Stakeholder Requirements identified, collected, and defined to develop Operational Capability Document (OCD) Chose CORE as the CASE tool to manage system technical requirements and produce System Specification part of Request for Proposal (RFP) Performance Requirements Constraints External System Interfaces Verification Methods for all requirements Model Provided as GFI Traceability to OCD System Functional and Physical Architecture Data Item Flow from External Systems Modified in transition to Capability Design Description (CDD) 9
AAG System Model Development (cont.) General Atomics Required to use A CASE tool, chose CORE to take full advantage of GFI system model Developed physical and functional representation at the subsystem and component level Derive Performance Requirements Derive Design Constraints Define Internal Interface Requirements Define Internal Data flow Flow Down of System Constraints (i.e. reliability, maintainability, and human factors) 10
AAG Physical Hierarchy SYS.1 Advanced Arresting Gear System SYS.1.1 Cross Deck Pendant Subsystem SYS.1.2 Energy Absorber Subsystem SYS.1.3 Dynamic Control Subsystem SYS.1.4 Drive Fairlead Subsystem SYS.1.5 Power Conditioning Subsystem SYS.1.6 Prime Power Subsystem SYS.1.7 Workstation Management Subsystem SYS.1.8 Thermal Management Subsystem SYS.1.9 Shock Absorber Subsystem SYS.1.2.1 Electric Motor SYS.1.2.2 Mechanical Brake SYS.1.2.3 Purchase Cable Drum SYS.1.2.4 Water Twister SYS.1.7.1 Air Boss Display SYS.1.7.2 Arresting Gear Operator Control Station SYS.1.7.3 HealthMAP SYS.1.7.4 Retract Operator Control Station SYS.1.7.5 Supervisory Control Server 11
AAG System Model Development (cont.) System Model used by General Atomics to Ensure flow down and traceability to procurement specification Enabled traceability to trade studies and design analysis Functional Baseline for Initial FMECA Produced: System Specification Subsystem Specifications Components Specifications Software Requirements Specifications Test and Evaluation Plans 12
AAG Test Program The AAG program has applied a cohesive integration and test strategy to verify the engineering development of the system. Component, subscale, and prototype level to verify concepts, validate the developmental arrestment model, and reduce risks Integration and reliability testing will reduce risk through integration of major components Environmental tests to ensure the system is qualified for the intended operational environment System level tests at Jet Car Test Site and Remote Aircraft Landing Site 13
AAG Test Documentation For the AAG program, The overall test strategy is captured Test and Evaluation Master Plan (TEMP) The developmental test framework is captured in the Test Evaluation Plans (TEP) in accordance with test strategy Detailed procedures are captured in the individual test directives Developmental tests will be documented in a series of test reports 14
Associating Requirements to Verification Methods REQUIREMENT IDENTIFICATION REQUIREMENT IDENTIFICATION (Function, Performance Index, Constraint) (Function, Performance Index, Constraint) VERIFICATION VERIFICATION METHOD METHOD SELECTION SELECTION ANALYSIS ANALYSIS INSPECTION, DEMONSTRATION, INSPECTION, & DEMONSTRATION, TEST & TEST TD Qualification Analysis System Simulation Engineering Analysis Reliability Analysis SDD Qualification Analysis System Simulation Engineering Analysis Reliability Analysis SDD Inspection Test SDD Controls / HealthMAP Software Software Unit Test Software Integrated Test SDD Prototype Subsystem & Component Tests SDD Integration & Extended Reliability Tests SDD Fairlead Tests & JCTS Commissioning SDD JCTS Functional & Performance Demonstration Tests SDD RALS Functional & Performance Demonstration Tests SDD Maintainability Tests Environmental Qualification Tests Humidity, Salt Fog, Shock, Vibration, Rain UE, Rain CE, Solar Radiation, Icing, Fluid Contamination, Sand & Dust, EMI, Extreme Temperatures Preparation For Delivery / Shipment Model Based Approach Developed the Test Plans and Specification Qualification Section 15
Map of Elements for Test Planning Requirement Requirement Functions, performance indices, interface, links, and constraints verified by Verification Method(s) Verification Method(s) i.e. Environmental Qualification, Functional Demonstration satisfied by Verification Event(s) Verification Event(s) constrains, allocated to, traces to, exhibited by Test Articles Test Articles ~ Component uses configuration defined by assigned to Test Configurations Test Configurations Test Procedures Test Procedures Responsible Responsible Organizations Organizations Instrumentation, facilities, and support equipment Test management, Test Directive, procedures, i.e. test director, reliability personnel, safety personnel, training, FRACAS process, environmental representative safety processes, security processes, reporting requirements, environmental requirements, installation requirements Schedule Schedule ~ Attribute 16
Lessons Learned Aggressive development schedule reduced adherence to : Bottom to top test plan development, Integration test plans completed before component requirements (and verification plans) fully developed Program leveraged integrated tests for the verification of a majority of the component requirements Through the process of assigning requirements to verification methods, the need for a substantial integrated test was clear Many requirements of component tests not achievable at component level due to design parameters beyond test fixture capability Integration test phase expanded to include additional major components of the system for risk reduction 17
Conclusions The model-based approach increases confidence that the system design solution is on track to meet requirements Discipline of the model-based approach ensures that performance capability and reliability are designed into the system early Development of the TEPs provided the program and stakeholders early visibility of the derived requirements, the planned verification, and the resources required Managers, design engineers, systems engineers, test engineers, logistics, etc. all contributed to the same product baseline Early identification of verification requirements provided better scheduling and resource budgeting 18