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ADI-advancedSIS.pdf
ADI
APPLIED DYNAMICS
INTERNATIONAL
Understanding Advanced System
Integration Labs: Simulation-Centric
System Integration
“This paper examines how successful aerospace and defense
organizations are changing their processes to apply simulationbased testing, evaluation, and system integration in a manner
that changes the competitive playing field within the industry. ”
Understanding Advanced System Integration Labs:
Simulation-Centric System Integration
Executive Summary
In order to meet the
challenges of these complex
and highly interoperable
systems, the System
Modeling and simulation have become key tools for the development of advanced aerospace and
defense vehicles. Simulation techniques and tools have been adopted at numerous stages in
an advanced development process and enable design teams to develop their products faster,
cheaper, and better.
Integration Lab (SIL) has
become a key component in
the development process.
As the use of simulation has gained momentum and become a necessary core competency for
any serious aerospace and defense organization, proliferation of the use of electronic systems has
also emerged in parallel. An estimated 80% of new system capability and complexity is inserted
through the use and expanded role of electronic systems. Advanced embedded electronic systems
collect and share more data to obtain greater operational awareness. This operational awareness
provides greater power efficiency, higher performance (using various measures), improved safety,
and much more. In order to efficiently implement a vehicle electronic system architecture able
to collect and share this massive amount of operational data, the system makes increasing use
of vehicle networks. The resulting vehicle design includes tightly networked electronic systems
dependent on time and event synchronous interoperability.
In order to meet the challenges of these complex and highly interoperable systems, the System
Integration Lab (SIL) has become a key component in the development process. The SIL is a risk
reduction facility where the complete vehicle, including software and hardware, can be integrated,
tested and evaluated for both stand alone functionality and interoperability prior to building the
first production prototype. The SIL provides a vehicle test facility that is a cross between a pure
simulation and the final system.
The SIL is a simulation-based tool with a proven track record of providing immense cost savings.
Performing system integration on a highly complex aerospace or defense vehicle is a very costly
activity with great potential for schedule delays and cost overruns.
Applied Dynamics has worked closely over the past several decades with leading aerospace and
defense companies to define and implement a highly effective simulation-centric development process. Simulation-centric development is a rapidly emerging approach for collaborative simulationbased design, testing, and integration that provides greater control over the development program,
reduces program risk, and has enabled those who embrace the concepts to obtain competitive
advantage in the aerospace and defense market.
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APPLIED DYNAMICS
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Introduction
This paper examines how successful aerospace and defense organizations are changing their processes to apply simulation-based testing, evaluation, and system integration in a manner that
changes the competitive playing field within the industry. Historically, aerospace and defense
companies have been organized with “stovepipes” between different functional groups. These
stovepipes are being eliminated and cross organizational processes are driving competitive advantage. Although space-technology-oriented illustrations are used throughout this paper, these
techniques are being applied in all areas of the aerospace and defense industry including military
modernization, and commercial aerospace.
Adding Simulation to the Design Process
“Prior to the use of simulation
and modeling, the “build and
break” approach to system
design was very slow and
costly.”
In a traditional system development approach the development process begins by defining requirements contained in a requirements document. The requirements document provides a tool for
managing the design of a complex system. From the requirements document, a textual design
specification is created. Ideally, the design specification provides complete documentation of
all aspects of the system design. The system design will evolve over the duration of the design
phase of the project. As the design specification becomes increasingly detailed, the design of
each subsystem begins to impose requirements for how that subsystem interfaces with other
subsystems in the vehicle. These imposed interface requirements are fed back and folded into the
requirements document.
Requirements Definition
Design Specification
Prototyping & Integration
A Traditional System Development Approach
Prior to the use of simulation and modeling the development of a vehicle required prototypes be
iteratively designed, built, tested, and re-designed. This “build and break” approach to system
design was very slow and costly.
ADI
In an effort to achieve more cost effective development programs, modeling and simulation
emerged as a method to reduce the number of iterations. Simulation provided a way to mathematically model each subsystem, or component within each subsystem, and iterate the mathematical representation to produce a superior design. Simulation became the preferred technique
for finding an optimal design for each subsystem. Upon completing the simulation and modeling
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activities the design was documented in the design specification. Although the design continued
to be largely textual, the use of simulation and modeling resulted in a better design and enabled the
development program to reduce the number of prototypes required to reach the final product.
Simulation
Model
Prototyping & Integration
Requirements Definition
Subsystem Design Spec.
Simulation in the Design Stage
“The resulting vehicle design
includes tightly networked
electronic systems, dependent on time and event synchronous interoperability, and
providing an immense level of
system complexity.
As simulation repeatedly demonstrated value through its ability to reduce development cost and
provide superior design, simulation tools became more capable and more widely used. The various segments of the simulation tool industry became increasingly competitive as aerospace and
defense companies made the shift away from in-house developed simulation tools toward bestin-class commercial tools. As the use of simulation gained momentum and became a necessary
core competency for any serious aerospace and defense organization, proliferation of the use of
electronic systems also emerged in parallel.
An estimated 80% of new system capability and complexity is now inserted through the use
and expanded role of electronic systems. Advanced embedded electronic systems collect and
share more data to obtain greater operational awareness. This operational awareness is used to
provide greater power efficiency, higher performance (using various measures), improved safety,
and much more. In order to efficiently implement a vehicle electronic system architecture able to
collection and share this massive amount of operational data, the system makes increasing use of
vehicle networks. The resulting vehicle design includes tightly networked electronic systems, dependent on time and event synchronous interoperability, and providing an immense level of system
complexity. This increased complexity has resulted in two trends.
The first trend is the move away from the textual design specification. Simulation is now used to
obtain an optimal design using a range of mathematical techniques. Today simulation models and
solid models provide a digital design specification for the vehicle. Feeding the design back into a
textual requirements document is a needless and onerous task. Efficient development programs
are abandoning the textual design specification in areas where the design is well-specified through
the use of simulation or solid models. The second trend is the increased use of the system integration lab.
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The System Integration Lab
It is only in recent years that aerospace & defense programs and companies have shown across the
board recognition of the importance of the System Integration Lab (SIL) and its role in the success
of a vehicle or weapon system program. The SIL has become a required component of any serious
defense program. As a result, defense contractors including Northrop Grumman, BAE Systems,
Raytheon, General Dynamics, and Lockheed Martin have made recent SIL facility investments.
A SIL is a risk reduction facility where software and hardware can be integrated, tested and evaluated for both stand alone functionality and interoperability prior to being fielded or flight tested.
The SIL is used to create a vehicle or weapon system test facility that is a cross between a pure
simulation and the final system. The SIL uses as many real vehicle subsystems as is technically and
economically feasible. Real control units, avionics, navigation systems, mission computers, flight
controls, and environmental control systems are connected in the SIL. Real-time simulation is used
to provide the functionality of those components of vehicle or weapon system operation that are
difficult or costly to bring into a lab such as aerodynamics, six degrees-of-freedom motion, extreme
temperatures, and low-gravity conditions.
The System Integration Lab
Simulation
Model
Electrical Interfaces &
Databuses
Simulation
Model
TCP/IP-based
Simulation Control
Simulation
Model
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PC-based
Test Interface
The SIL enables the vehicle to be tested around the clock, through a range of normal and extreme
operating conditions in a very cost effective manner. By connecting real electronic systems across
representative electrical and electronic interfaces to realistic representations of the vehicle, nearly
all aspects of the vehicle complexity can be tested and exercised using production vehicle electronic systems.
A well-designed SIL also provides a platform for future technology insertion. New technology can
be fully tested and certified in the SIL before it is ever installed in the vehicle for flight test.
The SIL is a simulation-based tool with a proven track record of providing immense cost savings.
However, performing system integration on a highly complex system is a very costly activity with
great potential for schedule delays and cost overruns. In order to reduce the risk and cost of system integration those most experienced in the use of a SIL are taking a collaborative approach that
starts well before the SIL.
Efficient, Collaborative Integration
“There are numerous
approaches to ensure supplier intellectual property is
protected”
Early examples of system integration took the approach of tasking a team to prepare the SIL for
production prototype delivery. This job included the development of all simulation models required
in the SIL, implementation of those models on real-time simulation computers, and readying the
simulation computers to have production electronic system prototypes plugged into the lab. This
approach had numerous pitfalls.
The integration team is rarely in a position where they are best qualified to develop the SIL simulation models. For example, if Pratt & Whitney Rocketdyne is supplying the rocket engine and the
engine controller then Pratt & Whitney Rocketdyne is in the best position to deliver an accurate
simulation model for the rocket engine. Historically it was very difficult to convince suppliers and
contractors to deliver simulation models to the SIL. The position of the contractors and suppliers
was that simulation models were part of their intellectual property and by supplying these models
they were at risk of having this intellectual property made available to competitors.
Program managers and lead system integrators have learned through years of experience that
in order to have a successful system integration phase of the program, all simulation models
required in the SIL must be included in the supply contract deliverables list. There are numerous
approaches to ensure supplier intellectual property is protected but if simulation models are not
included in the deliverables list then suppliers will resist. The most successful programs have
taken things one step further.
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Simulation
Model
Simulation
Model
Electrical Interfaces
& Databuses
Simulation
Model
TCP/IP-based
Simulation Control
Simulation
Model
Simulation Models &
Virtual Prototypes
Design Groups
& Suppliers
“By requiring suppliers and
design teams to deliver
simulation models at one or
more stages of maturity, the
SIL commissioning activity
can begin very early in the
program”
PC-based
Test Interface
System Integration Lab
Collaborative System Integration
As a means of further reducing program risk and enabling the system integration activity to be
parallelized, suppliers and design groups are required to deliver a real-time simulation “virtual prototype” and any necessary simulation models well-ahead of the production prototype integration
activity. These virtual prototypes are intended to behave identically to the final production prototype but:
• virtual prototypes do NOT need to be built using flight-worthy electronics
• virtual prototypes do NOT need to meet the final physical requirements (size, dimensions,
weight)
• virtual prototypes do NOT need to meet requirements such as power consumption, noise,
vibration, EMI, etc
Virtual prototypes are delivered for the purpose of spiraling incrementally toward the final fullyintegrated SIL. Virtual prototypes enable interoperability issues to be discovered very early in the
program at a point where the program cost implications can be minimized. Virtual prototypes
are typically built using commercial computer equipment such as PCI-based systems. As stated
above, virtual prototypes are “intended to behave identically to the final prototype”. However, it
must be recognized that various versions of the virtual prototype will be delivered as the design is
finalized, the performance is improved, and interoperability issues are resolved.
By requiring suppliers and design teams to deliver virtual prototypes and simulation models at one
or more stages of maturity, the SIL commissioning activity can begin very early in the program.
As the program progresses, early virtual prototypes are replaced with increasingly accurate virtual
prototypes and finally with production prototypes. This incremental approach to system integration ultimately results in shorter development schedules and reduced program cost.
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Virtual System Integration
When the SIL is first commissioned with a collection of virtual prototypes and simulation models
the lab is made up of numerous computers executing a collection of simulation models and embedded code. The most successful system integration projects have raised the questions:
• “Could I take this collection of simulation models and code, connect them appropriately,
and simulate the complete vehicle in non-real-time?”
• “If I could, what benefits would this provide to the system integration project?”
The answer to the first question is yes. The process of building this non-real-time simulation using
the simulation models and code from the SIL is referred to as building a “Virtual System Integration
Lab (VSIL)” and the use of a VSIL can provide numerous benefits to a development program.
Virtual System Integration Lab
Simulation
Model
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Developing a VSIL enables the vehicle integrator and suppliers to work in a manner far more efficient than the traditional approach to system integration. The VSIL allows program management to
place a virtual vehicle on the computer of every development team member early in the program.
The VSIL improves the communication of technical requirements and subsystem interfaces and
enables suppliers to assess the interoperability of their supplied subsystem earlier in the development program. In order to successfully implement a VSIL the integrator must take special care to
ensure that each supplier’s intellectual property is protected.
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The VSIL provides an ideal tool for training new members of the development team on vehicle
architecture, system behavior, and the SIL test language. In addition, the VSIL provides a powerful
tool for performing embedded software functional test.
The VSIL also provides a powerful tool for program management. The VSIL can be used to evaluate
supplier designs and adherence to system requirements. The VSIL allows program management
to assess a supplier’s simulation-based design capability early in the development program. Most
critically, the VSIL provides a tool to substantially reduce the load on the SIL facilities. Real-time
simulation projects and the complete suite of test cases can be developed away from the expensive SIL facilities. The VSIL provides substantial program cost savings and greatly reduces program
risk. For a more in-depth discussion on VSIL techniques and technology refer to the whitepaper
“System Integration Labs – Dramatic Cost Reduction using a VSIL”.
Simulation Centric Development
Combining formal requirements management, simulation-based design, the use of a virtual system
integration lab, and virtual prototypes all feeding into a system integration lab creates a highly
efficient, collaborative development process known as simulation-centric development. Simulation-centric development minimizes the duplication of effort and minimizes overall program risk by
enabling design teams and suppliers to test their vehicle subsystem in-context with the rest of the
vehicle at various stages of development. As each development group increments the maturity
of their design the maturity and complexity of the associated simulation models is incremented.
System simulations are shared amongst design teams to provide each team or team member with
a VSIL version of the vehicle. The VSIL vehicle can be used to exhaustively test and evaluate each
subsystem for stand-alone functionality and interoperability early in the program.
Simulation
Model
Electrical Interfaces
& Databuses
Simulation
Model
TCP/IP-based
Simulation Control
Simulation
Model
Requirements Definition
VSIL
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PC-based
Test Interface
System Integration Lab
Efficient Simulation-Centric Development
Design Groups
& Suppliers
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Simulation
Model
As designs mature, the VSIL simulation models are transferred to real-time simulation computers
and become virtual prototypes. Identical models are used during VSIL testing and virtual prototype
development. This approach eliminates duplication of effort, reduces the risk of finding interoperability problems in the SIL, and reduces the cost of implementing virtual prototypes.
Once the virtual prototype version of the SIL is integrated, the integration team can begin taking
the real-time simulated vehicle through a range of test scenarios. Stand-alone or interoperability
problems found during virtual prototype testing are fed back to the appropriate design team(s) allowing design changes to be made in a cost-effective manner.
Next, production prototypes are inserted in the SIL as they become available. Because the lab is
first commissioned using virtual prototypes, integrating the production prototypes is a simple matter of unplugging the virtual prototype and replacing it with the production prototype.
Simulation-centric development is an approach that minimizes the effort and risk associated with
the complete system integration exercise and provides the only cost-effective approach for tackling a highly advanced vehicle program.
The Rise of a Simulation Model Portability Standard
Simulation-centric development is a collaborative approach for aerospace and defense vehicle
development that is highly dependent on the ability to move simulation models between various stages of the development program, amongst various suppliers and development program
participants, and to various simulation computers platforms. A common, standardized simulation
model interface will increase the ease of working with potentially hundreds of simulation models
developed by disparate design teams. Although battlefield simulation model standards such as
HLA have been successfully developed and adopted industry-wide, to date there is no simulation
model portability standard that is appropriate for system integration.
In the early 1990’s the European Space Agency (ESA) recognized the need for a standard to
ensure portability between simulation platforms. This initial effort was called SMP1. SMP1 was
ultimately limited by the lowest common denominator of the simulation platforms for which it was
required to support.
Later the ESA launched the SMP2 initiative with the goal to move beyond the limitations of SMP1
and to define a standard that could be embraced by system integration labs of today and tomorrow. Unfortunately, SMP2 has not been widely embraced. A significant shortcoming of SMP2 is
that it only offers an object-oriented interface standard. The object-oriented restriction poses a
problem because of the predominance of procedural embedded code and procedural code-based
simulation modeling tools such as The MathWorks Simulink. As a result, SMP2 is not actively used
in the aerospace and defense industry.
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APPLIED DYNAMICS
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Defining a Simulation Model Portability Standard
A simulation model portability standard that meets the needs of the commercial aircraft, military
vehicles and weapons systems, and space programs could trigger significant advancements with
regard to the industry’s ability to work collaboratively.
Tools for Simulation-Centric Development
Applied Dynamics has work closely with major aerospace and defense companies and organizations including Boeing, Pratt & Whitney Rocketdyne, Raytheon, NASA, U.S. Navy, U.S. Air Force,
U.S. Army, General Dynamics, BAE Systems, Rolls-Royce, Honeywell, Gulfstream, and many more
to support system integration activities and real-time simulation. Over the past ten years vehicles
have become more complex and system integration has become more costly. In an effort to help
our customers become increasingly efficient we’ve developed and evolved the ADvantage Framework set of tools for simulation-centric development.
The ADvantage Framework supports popular commercial simulation modeling packages (Simulink,
SystemBuild, etc), various operating systems & compilers, and commercial-off-the-shelf computer
hardware to provide a software toolset that reduces the cost of implementing simulation-centric
development. ADvantage enables various simulation model types and embedded software coding
languages to be brought together to build a VSIL. As development progresses, ADvantage enables
the non-real-time VSIL to be quickly converted to real-time virtual prototypes, and later virtual
prototypes to be swapped out with production prototypes. The ADvantage Framework includes a
full test environment, a complete suite of test interaction capability, and sophisticated data logging
and analysis services.
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10
The ADvantage Framework has been field-proven on many of the most demanding aerospace &
defense programs including Boeing’s 787 Trent jet engine and aircraft braking projects, the Vertical Motion Simulator (VMS) at NASA Ames, the Army’s new FCS NLOS-C military ground vehicle
development, and Gulfstream’s G550 luxury aircraft integration lab, and has been used to develop
subsystems within NASA’s Space Shuttle Program and the International Space Station Program.
For more information on the ADvantage Framework refer to:
http://www.adi.com/products_sim.htm
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APPLIED DYNAMICS
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Applied Dynamics International, Inc.
World Headquarters
3800 Stone School Road
Ann Arbor, MI 48108-2499
USA
Applied Dynamics International, Ltd.
European Headquarters
1450 Montagu Court
Kettering Venture Park, Kettering
Northhamptonshire, NN15 6XR, UK
Telephone: 734.973.1300 x219
Facsimile: 734.668.0012
email: [email protected]
www.adi.com
Telephone: +44.1536.410077
Facsimile: +44.1536.410019
email: [email protected]
©2007 by Applied Dynamics International. All rights reserved. Version 1.0
ADvantage, ADvantageDE, ADvantageVI, and ADvantage Framework are trademarks of Applied Dynamics International.
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