Dana Peterson CSEP Acq dpetersondrsssicom 314 5534599 Illustrate a sample of Systems Engineering tools used on the Powered Trailer project to Resolve requirement issues Understand relationships between requirements ID: 934111
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Slide1
“A Systems Engineering Approach For Balancing Powered Trailer Requirements”
Dana Peterson (CSEP Acq)
dpeterson@drs-ssi.com
(314) 553-4599
Slide2Illustrate a sample of Systems Engineering tools used on the Powered Trailer project to:Resolve requirement issuesUnderstand relationships between requirementsPrioritize requirements
Get consensus on the best technology optionsProvide the best “balanced” overall solution
Purpose of Presentation
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INCOSE BRIEF @ DRS Technologies
Slide3Improve combined truck and trailer grade climbing and mobility in soft soil terrain conditionsProvide cargo and health status reporting over the C4I network
Provide limited trailer self-mobility for climbing aircraft/ship ramps under operator control
Provide on-board DC/AC export power for powering shelters and other equipment
Powered Trailer Project Goals
Powered Trailer
Focus is on Trailer Drive Technologies
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INCOSE BRIEF @ DRS Technologies
Slide4Requirements Traceability/ Rationale Matrix (RTRM)
N2
Diagram
Analytic Hierarchy Process (AHP)
Quality Function Deployment (QFD)
Morphological Analysis (MA)Architecture Views
Trade StudySensitivity Analysis
Affinity DiagramTree DiagramFishbone Diagram
Digraph
Blueprinting
Arrow Diagram
Matrix Diagram
Relations Diagram
Process Decision Program Chart
Flow Diagram
Context Diagram
Pugh Matrix
Specification
Sample SE Tools
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INCOSE BRIEF @ DRS Technologies
Slide5Systems Engineering Approach
Performance
Spec
User
Requirements
Requirements
Traceability/Rationale Matrix
(RTRM)
Requirement
Prioritization
QFD
House
Of Quality
Power Trailer
Design Alternatives
Mobility
Analysis
Trade Studies
-Performance
-Payload
-C-130 Transport
-R&M
-Cost
-Schedule
Technology
Options
Sensitivity
Analysis
Preferred
Solution
AHP
MA
Legend
AHP = Analytical Hierarchy Process
QFD = Quality Function Deployment
MA = Morphological Analysis
An Iterative Hierarchical Process That Provides the Best
Overall Requirements Balance
Slide6Many requirements in diverse functional areasA lot of stakeholders involved
Tools are needed to balance requirements and validate concept prior to project executionCost and schedule are receiving a lot more attention
Multi-Attribute Criteria Problem
Performance
Cost
Schedule
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INCOSE BRIEF @ DRS Technologies
Slide7Solution Synthesis is Becoming More Challenging
Design for Adaptability
Performance
Cost
Schedule
Design for Dynamic Value
Open Architecture
Modular Systems Approach
Design To Cost
Spiral Development
Rapid Response
Eco-Consciousness
People Resources
Company Mergers
Reorganization
Economic
Political
Cultural
Technology Advances
Part Obsolescence
Robust Design Techniques
Six Sigma
Agile Design
Security
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Slide8Prioritizing Requirements:Spiral 1, 2, 3 Evolution
Threshold Vs ObjectiveKey Performance Parameters Vs Key System Attributes Vs Additional Attributes
Tier Levels 1, 2, 3, 4Asking:
What Is Possible?
What Can Be Done Within Program Constraints and Current Technology?What Are The Tradeoffs?
Customers Now:
Provide Me With The Best Balanced Solution!
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INCOSE BRIEF @ DRS Technologies
Slide9RTRM Sample Sheet
(Transport & Trailer Requirements)
Statistics:
- Number of Requirement Paragraphs: 135 - Number of Stated Requirements: 250 - Requirements Needing Clarification: 20 (8%) - Number of Requirement Disconnects: 12 (5%)
Total Requirement Issues: 32 (13%)
RTRM Helps To Identify & Resolve Requirement Issues
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Slide10The N2 diagram
illustrates interfaces and relationships between system requirements, parameters, and metrics
System functions or elements are listed in the diagonal boxes
Interfaces and relationships are identified in the
off-diagonal boxes. Data flows in a clockwise direction between functions or elements
The next example illustrates a modified form of N2 where requirements have been listed in the diagonal boxes
System N
2 Diagram
Helps To Surface Interface Issues
N
2
Helps To Identify Interface Issues
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INCOSE BRIEF @ DRS Technologies
Slide11Example N2 Diagram
Mobility
Payload
Protection
Transportability
C4ISR/EW
Elec
Power
Supportability
GVW
Curb
Weight
Height
Mobility
%NO-GO <25
45-50 mph on 5% Grade
Payload: GVW
-CW-Crew
24” Ground Clearance Desired
Turning Radius of 25’
SA (FBCB2,
MTS)
Engine
Gen/ Alternator
Fuel Specifics
Diesel
80 gm/kWh
JP8 88 gm/kWh
Pwr to Weight Ratio
>
30 bhp/ton
See GVW
t/2h
≥ 1.20 for Stability
Payload
Suspension
Max Payload at 5100
lbs
Weight Trades
Essential Combat Configuration (ECC)
C2 Equip
Med
Equip
Weight Trades
Sustainment Supplies
for 3 Days
Weight Trades
Payload
to Curb Weight Ratio ≥ 0.5
H=76” for MPF
102” C-130
Protection
Protection for Crew
Vs. Weight
KE, MINE,
IED, Overhead
Ease of B-Kit
Armor R/R
Threat Types & Locations
Active Armor Protection
Armor
Repair Costs
Weight Trades
Integral Armor
GPK, CROWS,
Weapons
Transportability
(2) C-130,
CH-47, CH-53,
MPF
Operator Remote Control
Climbing Ramps
Trailers
18,000
lbs
(2) On C-130
12,000 lbs Desired
H=76”
for MPF 102” C-130
C4ISR/EW
Obstacle
Avoidance
Net-ready, C2, FBCB2, MTS
Silent Watch
(2 Hours)
RFID
C2
Equip Weight
C2 Equipment
Weight
Antennas
Elec Power
Hybrid Drive Option
15 kW
OB
10 kW Exp
Exp Power
Weight Trades
A-Kit
Vs
B-Kit
Supportability
Fuel Efficiency
60
ton-mpg
400 mile range
Stowage
Items
BII
Health Mgt.
CBM
+
A
0
=95%
MMBF=10,000
for Production
GVW
Acceleration
13,000
lbs Max.
Axel Loading
Not Specified
GVW: CW + Payload + Crew
Height Impacts Weight
Curb Weight
Weight Trades
Weight Trades
13,000
lbs Max.
Axel Loading
Not
Specified
Height Impacts
Weight
Height
Suspension
< 157.5
” for Berne Tunnel
Slide12Proven, effective means to deal with complex decision making involving multiple criteriaCaptures both subjective and objective evaluation measures
A hierarchal decomposition of requirements or goals is accomplishedPair wise comparisons of requirement attributes are made and relative scores computed for each leaf of the hierarchy
Scores are then synthesized yielding the relative weights at each leaf as well as for the overall model
A coherent assessment is reached when Inconsistency Ratio < 0.1 (http://people.revoledu.com/kardi/tutorial/AHP/Consistency.htm)
Analytical Hierarchy Process (AHP)
AHP Helps to Determine Relative Importance
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INCOSE BRIEF @ DRS Technologies
Slide13Model
Level 1
Mobility
Transportability
Survivability
C4IRS/EW
Power
Management
Supportability
Payload
Model
Level 2
GVW
Driver Vision
Stability
Speed
HP/ton
Operational Range
CW
Height 76in
Axle Loading
30 min Ready
CREW2.1
SD Weapon
CBRNE
Signature Mgt
Ballistics Protection
C3
SA
Net Security
Bus Architect
Power Buses
OB Power
Export Power
Electrical Storage
RAM
Health Mgt
HFE
O&S Cost
Commonality
Flatrack (3,200 lb)
Cargo (22,000 lb)
Model
Level 3
Fuel efficiency (ton-mpg)
Fuel Capacity
Armor Protection
LVOSS
Visual signature
Thermal signature
EM signature
Direct Fire
IED
Mine
Anti-tank
Blast Protection Seats
Crush resistant roof
Model
Level 4
Fuel Specifics
ECU Map
Legend:
GWV =Gross Vehicle Weight, CW = Curb Weight, C3 = Command, Control, Communications, SD = Self-Defense, SA = Situational Awareness, OB = On-Board, DVE = Driver Vision Enhancer, CBRNE = Chemical, Biological, Radiological, Nuclear Effects, IED =Improvised Explosive Device, LVOSS = Light Vehicle Obscuration Smoke System, LCC = Life Cycle Cost, UPC = Unit Production Cost
Requirements Model Breakdown
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Slide14Combinatorial Trade Study- Requirements Importance
Level 1 Requirements
– Per Customer Attribute Weights (weights can be modified for tradeoff purposes)
Mobility
0.14
Payload
0.20
Transportability
0.20
Survivability
0.10
C4ISR/EW
0.13
Power Mgt
0.07
Supportability
0.16
Total
1.00
Notes:
If Row and Column
are of equal importance then 1; minimize use of 1
If Row
more important than Column then 2
If Column more important than Row then 0
Only need to assess White pairs; Gray pairs are diagonal
or self-calculated
Level 2 Requirements-
Mobility
GVW
Drive
r Vision
Roll Stability
Top Speed
Hp/ton
Operating Range
Weighting
Normalized
Global
GVW
1
0
0
2
0
0
3
0.083
0.012
Drive Vision
2
1
1
2
1
2
9
0.250
0.035
Roll Stability
2
1
1
2
2
2
10
0.278
0.039
Top
Speed
0
0
0
1
0
0
1
0.028
0.004
Hp/ton
2
1
0
2
1
1
7
0.194
0.027
Operating
Range
2
0
0
2
1
1
6
0.167
0.023
Totals
36
1
0.140
Level 3 Requirements
- Operating Range
Fuel Efficiency
Fuel Capacity
Armor
Protection
Weighting
Normalized
Global
Fuel Efficiency
1
0
2
3
0.333
0.0078
Fuel
Capacity
2
1
2
5
0.556
0.0130
Armor
Protection
0
0
1
1
0.111
0.0026
Totals
9
1.000
0.023
Level 4 Requirements-
Fuel Efficiency
Fuel Specifics
ECU Map
Weighting
Normalized
Global
Fuel Specifics
1
2
3
0.750
0.0058
ECU Map
0
1
1
0.250
0.0019
Totals
4
1
0.0078
Analytical Hierarchy Process Snapshot
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INCOSE BRIEF @ DRS Technologies
Slide15There are many customersThere are stated and unstated requirements
QFD helps to prioritize requirements and their tradeoffsQFD makes invisible requirements and strategic advantages visibleQFD helps to define which improvements provide the most gain
QFD promotes Team Consensus
QFD provides a documented audit trail for decisions
Quality Function Deployment (QFD)
The “House of Quality” Captures the Voice of the Customer
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INCOSE BRIEF @ DRS Technologies
Slide16“House of Quality”
Interrelationships between Technologies
Technologies
(Voice of the Company)
Requirements/Desires
(Voice of the Customer)
Planning Matrix
-Requirements Importance -Percent Improvement Desired -Marketing Competition Assessment
Relationships between Requirements and Technologies
Prioritized Technologies
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Slide17Two meetings were conducted with shareholders to get consensus on the Powered Trailer “House of Quality”Body of MatrixCommon definition/scope for each requirement and technical attribute agreed to
Reinforced relationship values - by convention:(0-none, 1-weak, 3-moderate, 9-strong)Recognized the most important associationsSegregated positive and negative correlations, ensured they were mutually exclusive
Achieved Consensus, Consensus, ConsensusQFD was finalized via (2) additional WebEx conferences
Powered Trailer QFD Analysis
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INCOSE BRIEF @ DRS Technologies
Slide18Powered Trailer “House of Quality”
Slide19Powered Trailer “House of Quality”INCOSE BRIEF @ DRS Technologies
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Slide20(Excludes Technical Difficulty and Cost Factors)
QFD Relative Ranking
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INCOSE BRIEF @ DRS Technologies
Slide21Combining individual preferences to form a group utility function presents a problemThe use of averaged group preference data in product design optimization can lead to erroneous results
This problem may not always be self-evident in the analysis of complex systems and products
Arrow’s Impossibility Theorem
(A Word of Caution!)
Provides a Hierarchical Model For Doing Tradeoffs
Group Consensus Must Be Reached To Avoid This Problem
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Slide22Designed for multi-dimensional, non-quantifiable problem complexesExplores boundary conditionsInvestigates the total set of possible relationships and “configuration” alternatives
Rules out alternatives that are inconsistent or incompatible using cross-consistency assessment
Morphological Analysis
MA Ensures No Alternative is Overlooked
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Slide23Morphological Field Example:
75 cells or configurations (Zwicky, 1969, p. 118.)
3-Parameters: color, texture, size
Color
: 5 discrete values: red, green, blue, yellow, brown
Texture: 5 discrete values: smooth, serrated, rough, grainy, bumpySize: 3 discrete values: large, medium, small
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INCOSE BRIEF @ DRS Technologies
Slide24MA-Trailer Drive Alternatives
No.
Vehicle Output Energy Form
Trailer Drive
Consistency?
YES/NO
1
Mechanical
Mechanical
YES
2
Mechanical
Electrical
NO
3
Mechanical
Hydraulic
NO
4
Mechanical
ICE
NO
5
Electrical
Mechanical
NO
6
Electrical
Electrical
YES
7
Electrical
Hydraulic
NO
8
Electrical
ICE
NO
9
Hydraulic
Mechanical
NO
10
Hydraulic
Electrical
NO
11
Hydraulic
Hydraulic
NO
12
Hydraulic
ICE
NO
13
None
Mechanical
NO
14
None
Electrical
NO
15
None
Hydraulic
NO
16
None
ICE
YES
17
None
Hybrid Electric
YES
18
None
Hybrid Hydraulic
YES
(5) Drive Alternatives Remain in Trade Space
Vehicle Output
Energy Form
Trailer Drive Type
Mechanical
Mechanical
Electrical
Electrical
Hydraulic
Hydraulic
None
Internal Combustion Engine (ICE)
Hybrid Electric
Hybrid Hydraulic
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Number of Configurations or Alternatives
4 X 6 =
24
Ruled
out Combinations of Output Energy and Hybrid 3 X 2 =
06
18
Alternatives to
Investigate
→
Slide25ALT #1 Electric PTO -Electrical Power Take Off provided by the transport
ALT #2 HEV -Series Hybrid Electric Vehicle with ICE, generator, and battery packALT #3 HHV -Hybrid Hydraulic Vehicle with hydraulic power provided by an ICE driven power pack
ALT #4 Mechanical PTO
-Mechanical Power Take Off provided by the transport
ALT #5 ICE Drive -ICE (210 HP with 340 ft-lb torque) with conventional drive train
Powered Trailer Design Concepts
ICE = Internal Combustion Engine25
INCOSE BRIEF @ DRS Technologies
Slide26395/85 R20 XZL tiresCentral Tire Inflation System (CTIS)Pneumatic Anti-Lock Brake System (ABS)
Serial communications with transportControl of mobility assist and CTISReceipt of trailer health and cargo load status
Independent Suspension
Trailer bed basic design
Features Common To All Concepts
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INCOSE BRIEF @ DRS Technologies
Slide27ALT #1 Elect PTO
ALT #2 HEV
ALT #3 HHV
ALT #4 Mech PTO
ALT #5 ICE Drive
Architectural Views for
all Five Alternatives
Concepts
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Slide28Physical Characteristics
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Slide29ALT #1 Elect PTO Components
Detail Needed for Credible Cost & Schedule Estimates
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Slide30Cost Vs Key Requirements Met
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INCOSE BRIEF @ DRS Technologies
Slide31Trade Parameters
Requirement
Weightings
Alt #1
Elect PTO
Alt #2
HEV
Alt #3
HHV
Alt #4
Mech PTO
Alt #5
ICE
Drive
Mobility Assist
5
|
5
3
5
4
3
5
Self Mobility
3
|
3
0
5
4
0
4
Payload
4
|
4
5
4
4
5
4
Complexity (RAM)
2
| 4
4
2
2
5
3
Interoperability
4
|
4
3
4
1
2
4
Maturity
2
| 4
4
3
2
5
5
Commonality
3
| 2
4
4
1
1
2
Unit Prod Cost
4
|
4
4
1
1
5
3
Weighted Score
91
|103
98
|104
67
| 74
86
|105
103
|117
Normalized Score
1.36
|1.39
1.46
|1.41
1
| 1
1.28
|1.42
1.54
|1.58
Comparison of Alternatives
Weighting/Scoring 0-5 with 5 Best
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Slide32Understanding requirements; their relationships, and relative importance:Tools: RTRM, N2 Diagram, AHPGetting consensus on the best technology options for meeting customer needs:
Tools: QFD (House of Quality)Evaluating alternatives:Tools: AHP, MA, Architectural Views
Selecting the best alternative:Tools: Trade Study, Sensitivity Analysis
SE Tool Usage Summary
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INCOSE BRIEF @ DRS Technologies
Slide33SE Process Critical for Providing Best Balanced SolutionSE Tools Assist in:Understanding requirements and their relationships
Getting consensus on which technology options provide the greatest benefitsAssuring no viable alternative is overlooked
Performing meaningful tradeoffs and sensitivity analysisMaking decisions involving multiple attribute criteria
Conclusions
Capturing the Results in the Requirements Set
Reduces Program Execution Risks
Go to:
www.incose.org
for more information
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Slide34Questions ?
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