Systems Engineering For Professional Engineers
Transcript of Systems Engineering For Professional Engineers
Systems Engineering
For
Professional Engineers
Stanley N. Hack, D.Sc., PE
November 12, 2012
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PRESENTATION GOALS
• Define Systems Engineering.
• Explain why stakeholders require Systems
Engineering to be an integral part of the
engineering process.
• Provide an understanding of why Systems
Engineering is an important component of all
engineering work.
• Clarify who performs the Systems Engineering
tasks.
• Illustrate the Systems Engineering Process.
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PRESENTATION SCOPE
• Overview of Systems Engineering:
o Systems Engineering definition.
o Systems Engineering stakeholders.
o Systems Engineering goals.
o Definition of Systems Engineer.
• Deeper dive into the Systems Engineering
Process using simple examples:
o My barn.
o Indy car.
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SYSTEMS ENGINEERING DEFINITION
Systems Engineering is a structured process that incorporates a
multidisciplinary team to develop systems from concept
development through their entire life cycle. Systems Engineering
considers the business and the technical needs of all stakeholders
to result in quality, useful, and sustainable products.
• International Council on Systems Engineering (INCOSE), 1999
Systems Engineering integrates all the disciplines and specialty groups into a team effort forming a structured development process that proceeds from concept to production to operation. Systems Engineering considers both the business and the technical needs of all customers with the goal of providing a quality product that meets the user needs.
• IEEE Standard for Application and Management of the Systems
Engineering Process, 1994
An interdisciplinary, collaborative approach that derives, evolves, and verifies a life-cycle balanced system solution which satisfies customer expectation and meets public acceptability.
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SYSTEMS ENGINEERING DEFINITION
Systems Engineering is a structured process that incorporates a
multidisciplinary team to develop systems from concept
development through their entire life cycle. Systems Engineering
considers the business and the technical needs of all stakeholders
to result in quality, useful, and sustainable products.
• MIL-STD-499A, Engineering Management, 1974
A logical sequence of activities and decisions that transforms an operational need into a description of system performance parameters and preferred system configuration.
• MIL-STD-499B, Engineering Management, 1994
An interdisciplinary approach that encompasses the entire technical effort, and evolves into and verifies an integrated and life-cycle balanced set of system people, products, and process solutions that satisfy customer needs.
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SYSTEMS ENGINEERING DEFINITION
Systems Engineering is a structured process that incorporates a
multidisciplinary team to develop systems from concept
development through their entire life cycle. Systems Engineering
considers the business and the technical needs of all stakeholders
to result in quality, useful, and sustainable products.
• The Engineering Design of Systems, Dennis M. Buede, 2000
The objective of Systems Engineering is to provide a system that accomplishes the primary objectives set by the stakeholders, including those objectives associated with the creation, production, and disposal of a system.
• A Practical Guide to SysML, Friedenthal, Moore, and Steiner, 2012
Systems Engineering is a multidisciplinary approach to develop balanced system solutions in response to diverse stakeholder needs. Systems Engineering includes the application of both management and technical processes to achieve this balance and mitigate risks that can impact the success of the project.
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IMPORTANT DEFINITIONS
System An integrated composite of elements (components, subsystems, modules,
people, and processes) that interact with one another and with their
collective external environment to provide a capability that achieves a set of
common objectives via the accomplishment of a set of tasks.
System of Systems A collection of task-oriented or dedicated systems that pool their resources
and capabilities together to create a new, more complex system which
offers more functionality and performance than simply the sum of the
constituent systems. System members of a System of Systems interact
with one another via interfaces that are external to each system member.
Decomposition A process of dividing components, processes, and problems into an
inclusive hierarchical set of simpler components, processes, and problems.
Model Any incomplete representation of reality. A model is an abstraction
constrained by fidelity and performance.
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A SHORT HISTORY OF SE
• Concepts of Systems Engineering have been traced back to the
early 1900’s at Bell Labs.
• The term Systems Engineering dates to the early 1940’s at Bell
Labs.
• The RAND Corporation was founded in 1946 by the US Air
Force. It created Systems Analysis, which is an important
aspect of today’s Systems Engineering.
• Systems Engineering as we know it today was first taught at
MIT in 1950.
• The US Department of Defense entered the world of Systems
Engineering in the late 1940s with the initial development of
missiles and missile-defense systems.
• Formation of the International Council on Systems Engineering
(INCOSE) in 1990.
Sources: 1) The Engineering Design of Systems, Models, and Methods, Dennis M. Buede, 2000
2) www.incose.org
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SE STAKEHOLDERS
• Customer Stakeholders
o Executives
o Users
o Maintainers
• External Stakeholders
o Inspectors
o Neighbors
o Government
o Vendors
o Prime Contractor
o Subcontractors
• Internal Stakeholders
o Executives
o Engineering Disciplines
o Architects
o Manufacturing
o Quality Assurance
o Sustainment and Support
o Training
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SYSTEMS ENGINEERING GOALS
The Systems Engineering Process must answer the following:
• What is to be engineered (designed / developed / built / studied / analyzed /
modified …)?
• How will the engineering be performed?
• Who is to perform the engineering tasks?
• When will the engineering tasks be performed?
• What is the cost of the engineering?
• When is the engineering finished? How do we know this?
Systems Engineering tasks are often integrated into the tasks of the lead
engineer or project manager. These tasks can be performed informally or
in a highly documented formal fashion resulting in a large quantity of
artifacts (documents). The required formality of the Systems Engineering
Process is directly dependent upon the level of a project’s complexity. The
design and construction of a pole barn (our example) requires no Systems
Engineering as an independent activity. The design and construction of a
nuclear power plant requires an extremely high level of formality in its
System Engineering Process.
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Most engineers have performed at least some aspects of Systems
Engineering as integral parts of their design and development activities.
Very large development efforts, such as developing an airliner or
designing a nuclear power plant, depend on Systems Engineering as
an independent discipline to manage the program technically. There is
something for all engineers to learn by understanding the Systems
Engineering Process.
• Informal Systems Engineering
o Often performed by engineering team members who support multiple
technical tasks.
o Results in artifacts (documents) that are integrated into the project’s
documentation package.
• Formal Systems Engineering
o Often performed by a team of engineers who are dedicated to the
Systems Engineering tasks.
o Results in a large number of dedicated artifacts (documents).
o Provides a means of tracing requirements throughout all aspects of a
system’s life-cycle.
THE SYSTEMS ENGINEER
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SYSTEMS ENGINEERING PROCESS
To understand the Systems Engineering Process via
an example, let’s build a barn and consider designing
an Indy car.
• First, we will look at the components of the Systems Engineering
Process.
• Second, we will apply each of the process components to building
the barn.
• Show limited examples applying the Systems Engineering
Process to the design of an Indy car.
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SYSTEMS ENGINEERING PROCESS
“V” Model
From: K. Forsberg and H. Mooz, The relationship of systems engineering to the project cycle, Engineering Management Journal, 4(3), 36-43, 1992
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“SIMILAR” Process • State the Problem
• Investigate Alternatives
• Model the System
• Integrate
• Launch
• Asses Performance
• Re-Evaluate
The significance of the SIMILAR Process
is the incorporation of re-evaluation
feedback loops at every step. Note that
the feedback loops encompass the
present step and all previous steps. This
use of constantly re-evaluating introduces
concepts of the Agile Development
Paradigm into the Systems Engineering
Process.
SYSTEMS ENGINEERING PROCESS
A. T. Bahill and B. Gissing, Re-evaluating systems engineering concepts using systems thinking, IEEE
Transaction on Systems, Man and Cybernetics, Part C: Applications and Reviews, 28 (4), 516-527, 1998
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Apply tailored process to each of
the Life Cycle Functions
From: Systems Engineering Fundamentals, Defense Acquisition University Press, 2001
SYSTEMS ENGINEERING PROCESS
“V” Model
“SIMILAR” Process
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US Government acquisitions depend on Technical Management (SE),
Business Management, and Contract Management.
ENGINEERING PROGRAM PROCESS
US Government
Technical
Reviews and
Artifacts (software system
development)
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STAKEHOLDER REQUIREMENTS
Stakeholder
Requirements
BARN
• Requirements:
o Shall be of sufficient size to hold three
automobiles and include a workshop.
o Shall have sufficient height to house an
automobile lift.
o Shall provide entry/exit access for three
automobiles.
o Shall meet all codes.
o Shall support applicable snow loads.
o Shall be attractive.
• Constraints:
o Budget.
o Location.
INDY CAR
• Requirements:
o Shall meet all formula requirements.
o Shall have top speed of 230+ mph.
o Shall have a forward acceleration of 1.0 G.
o Shall brake with a deceleration of 3.0 G.
o Shall have a lateral acceleration of 4.0 G.
o Shall consume no more than 1.75 liters/km
of fuel at maximum speed.
• Constraints:
o Budget.
o Laws of physics!
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System
Requirements
SYSTEM REQUIREMENTS
• Stakeholder:
o Shall be of sufficient size to hold three
automobiles and include a workshop.
o Location.
o Shall have sufficient height to house
an automobile lift.
o Shall provide entry/exit access for
three automobiles.
o Shall meet all codes.
o Shall support applicable snow loads.
o Shall be attractive.
o Budget.
BARN
• System Requirements:
o Size and layout.
o Height.
o Building, foundation, and
roof type.
o Materials.
System requirements are derived from stakeholder
requirements and constraints, or they are added to fill voids.
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System
Requirements
SYSTEM REQUIREMENTS
TRADE STUDIES and ANALYSES
Trade Trade Space
Building Type • Post and beam (Pole Barn)
• Stick-built on footers
• Stick-built on piers
Roof Structure • Beam and rafters
• Truss
Roof Type and Pitch • Gable – 12/6, 12/4 (12/6)
• Hipped – 12/6, 12/4
• Lean-To
Siding Material • Wood – board and bat, plywood (T1-11)
• Vinyl
• Steel
Roof Material • Shingles
• Steel
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SYSTEM ARCHITECTURE
Architecture • System Design
• Topology
• Behavior
• Interfaces
• Component Definitions
System Design and Architecture
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VERIFICATION AND VALIDATION PLAN
Verification and
Validation Plans
Verification – Did you build what you planned to build?
– Does the system meet the System Requirements?
Validation – Does the system do what it is supposed to do?
– Does the system meet the Stakeholder Requirements?
Test Plan – The Verification and Validation Test Plan is often
considered to be the most important document
developed within the Systems Engineering Process. It
defines when the project is finished.
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Verification and
Validation Plans
VERIFICATION AND VALIDATION PLAN
Indy Car Validation Plan • The following tests shall be made during
test run at racing speeds of at least 10 laps
on a 2.5 mile oval track:
o Top speed shall be measured at the end
of the straight-a-ways using a Model xxx
speed radar and shall exceed 230 mph.
o Maximum lateral acceleration shall be
recorded by a Model xxx accelerometer
and shall exceed 4.0 G.
• The following tests shall be made during
threshold braking from a speed of at least
150 mph:
o Maximum braking deceleration shall be
recorded by a Model xxx accelerometer
and shall exceed 3.0 G.
Indy Car Verification Plan • Engine horsepower shall be measured
using a Model xxx dynamometer and
shall exceed xx HP.
• Suspension travel at the front wheels
shall be measured using a Model xxx
caliper and shall be in the range of xx
to xx cm.
• Turning radius of a full circle traveled
under steering lock in both directions
shall be measured with a Model xx tape
measure and not exceed xx m.
• Front wing area shall be measured with
a Model xx tape measure and shall not
exceed xx cm2.
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COMPONENT REQUIREMENTS
Component and
Module
Requirements
BARN
• Posts – material, strength
• Beams – material, strength
• Rafters – material, strength
• Trusses – size and pitch
• Siding – material, color
• Roofing – material, color
• Overhead Doors – material, color
• Entry Doors – material, color
• Windows – type, size, material, color
• Soffit – material, color
• Fascia – material, color
• Trim – material, color
Note: All components are commercial
off-the-shelf (COTS)
INDY CAR
• Chassis
• Suspension
• Brakes
• Body
• Engine
• Transmission
• Controls
• Maintenance
Note: Most components are custom built for
this application. Their requirements are
derived from the system requirements
and are derived through considerable
analyses and trade studies.
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COMPONENT DESIGN
Component and
Module Design
• Specify commercial off-the-shelf (COTS) and purpose-built components.
• Design purpose-built components.
• Design modules and subsystems (interconnected collections of components).
• Barn Example
o Specify poles based on loading.
o Design nail-laminated poles.
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COMPONENT UNIT TEST PLANS
Component and Module Test Plan
Unit Test Plan for Each Component, Module, Subsystem
• Develop test procedure
• Specify test fixtures
• Specify test stimulation inputs
o Specify source of inputs
o Develop models to provide input stimulation
• Specify expected outputs
o Specify output sinks (data recorders, etc.)
o Develop models to predict expected outputs
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BUILD AND ASSEMBLE COMPONENTS
Component and
Module Build and
Assemble
BARN
• Posts
• Overhead Door
• Entry Doors
• Windows
INDY CAR
• Chassis
• Suspension
• Brakes
• Body
• Engine
• Transmission
• Controls
• Jack System
• Monitoring Computer
• Telemetry System
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Component and
Module Unit Test
UNIT TEST
BARN
• Posts – by inspection
• Overhead Door
o Inspection
o Range of motion
o Spring tension
• Entry Doors
o Inspection
o Range of motion
• Windows – by inspection
INDY CAR
• Formula Rules
o Inspection
o Dimensions
o Weights
o Specifications
• Chassis
o Dimensions
o Flex
• Engine – dynamometer testing
o Specs (HP, max RPM, etc.)
o Endurance
o Size and weight
• Etc.
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SYSTEM INTEGRATION
System
Integration
• Barn – build it
• Indy Car
o Assemble car
o Connect all interfaces
System Integration is the assembly phase of building a system. For
complex systems, such as a commercial aircraft, this is often the first
opportunity to verify that all unit tested components fit as architected.
For a commercial aircraft, System Integration is the building out of the
air frame with the system components such as engines, wiring
harnesses, hydraulic lines, control systems, seats, …
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VERIFICATION AND VALIDATION
System
Verification and
Validation
Verification – Perform formal Verification Test Plan.
– Did you build what you planned to build?
– Does the system meet the System Requirements?
Validation – Perform formal Validation Test Plan.
– Does the system do what it is supposed to do?
– Does the system meet the Stakeholder Requirements?
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Operational Tests
OPERATIONAL TESTS
Operational tests are sometimes included in the
Systems Engineering Process. Often, they occur
after Stakeholder Acceptance. The are generally in
situ evaluations of systems in their operational
environments. Faults uncovered during operational
tests are generally corrected under warranty.
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STAKEHOLDER ACCEPTANCE
Stakeholder
Acceptance
Stakeholder acceptance is a contractual event. A well
executed System Engineering Process results in the artifacts
necessary to satisfy the technical aspects of a contractual
obligation. In other words, the System Engineering Process
answers the question: When is the engineering finished?
$$
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SUMMARY
• All engineers perform Systems Engineering tasks at some
level of formality.
• The level of formality of the Systems Engineering Project is
directly related to the size and complexity of the project.
• Regardless of the formality level taken, the Systems
Engineering Process must answer the following:
o What is to be engineered (designed / developed / built / studied /
analyzed / modified …)?
o How will the engineering be performed?
o Who is to perform the engineering tasks?
o When will the engineering tasks be performed?
o What is the cost of the engineering?
o When is the engineering finished? How do we know this?
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QUESTIONS?
?