A Systems Engineering Approach For Balancing Powered

Report
“A Systems Engineering Approach For
Balancing Powered Trailer Requirements”
Dana Peterson (CSEP Acq)
[email protected]
(314) 553-4599
Purpose of Presentation
• Illustrate a sample of Systems Engineering
tools used on the Powered Trailer project to:
– Resolve requirement issues
– Understand relationships between
requirements
– Prioritize requirements
– Get consensus on the best technology
options
– Provide the best “balanced” overall
solution
INCOSE BRIEF @ DRS Technologies
2
Powered Trailer Project Goals
Powered
Trailer
• Improve combined truck and trailer grade climbing
and mobility in soft soil terrain conditions
• Provide 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
Focus is on Trailer Drive Technologies
INCOSE BRIEF @ DRS Technologies
3
Sample SE Tools
• Requirements Traceability/
Rationale Matrix (RTRM)
• N2 Diagram
• Analytic Hierarchy Process
(AHP)
• Quality Function Deployment
(QFD)
• Morphological Analysis (MA)
• Architecture Views
• Trade Study
• Sensitivity Analysis
•
•
•
•
•
•
•
•
•
•
•
•
•
Affinity Diagram
Tree Diagram
Fishbone Diagram
Digraph
Blueprinting
Arrow Diagram
Matrix Diagram
Relations Diagram
Process Decision Program Chart
Flow Diagram
Context Diagram
Pugh Matrix
Specification
INCOSE BRIEF @ DRS Technologies
4
Systems Engineering Approach
User
Requirements
Performance
Spec
Requirements
Traceability/
Rationale
Matrix
(RTRM)
Mobility
Analysis
Legend
AHP = Analytical Hierarchy
Process
QFD = Quality Function
Deployment
MA = Morphological
Analysis
AHP
Requirement
Prioritization
QFD House
Of Quality
Power Trailer
Design Alternatives
MA
Technology
Options
Trade Studies
-Performance
-Payload
-C-130 Transport
-R&M
-Cost
-Schedule
Sensitivity
Analysis
Preferred
Solution
An Iterative Hierarchical Process That Provides the Best
Overall Requirements Balance
Multi-Attribute Criteria Problem
• Many requirements in diverse functional
areas
• A lot of stakeholders involved
• Tools are needed to balance requirements
and validate concept prior to project
execution
• Cost and schedule are receiving a lot more
attention
Performance
INCOSE BRIEF @ DRS Technologies
6
Solution Synthesis is Becoming
More Challenging
Part Obsolescence
Technology
Advances
Reorganization
Cultural
Robust
Design
Techniques
Design for Adaptability
Spiral Development
Six Sigma
Political
Modular
Systems
Approach
Rapid
Response Open
Architecture
Performance
Security
Agile Design
Design To Cost
People
Resources
Design for Dynamic Value
Company
Mergers
Economic
Eco-Consciousness
INCOSE BRIEF @ DRS Technologies
7
Customers Now:
• Prioritizing Requirements:
– Spiral 1, 2, 3 Evolution
– Threshold Vs Objective
– Key Performance Parameters Vs Key
System Attributes Vs Additional Attributes
– Tier Levels 1, 2, 3, 4
• Asking:
– What Is Possible?
– What Can Be Done Within Program
Constraints and Current Technology?
– What Are The Tradeoffs?
Provide Me With The Best Balanced Solution!
INCOSE BRIEF @ DRS Technologies
8
RTRM Sample Sheet
(Transport & Trailer Requirements)
POWERED TRAILER
REQUIREMENTS TRACEABILITY/RATIONALE MATRIX (RTRM)
Source
78
Derived from The MSV at GCW must negotiate the 30% side slope. The
ORD lines companion trailer is assumed coupled to the truck. This
300 - 304
requirement must be met with either side of the vehicle facing
uphill. At what speed does this need to be meet? Definitely
need to check stability
x
Derived from The Mobility Rating Speed (MSR) and the Percent Go/No Go in
ORD lines soft soil for the MSV must be equal to or greater than the FCS
308 - 309
vehicle. Therefore, the trailer should provide equal performance.
We need to determine what the FCS requirement is.
x
79
80
81
30% Side Slope
Soft Soil Mobility
equal to or greater
than FCS
Central Tire Inflation ORD lines
System (CTIS)
329 - 337
FTTS will have
variable height
Program
charts
Comments/Requirements Rationale
Spiral Spiral Spiral 3 Draft Trailer Requirement based on FTTS ORD unless specified
1
2
Prod otherwise
Item Reqmt/Short
Description
The requirement is to be able to adjust the MSV/trailer tire
pressures to improve cross country mobility. The range of
parameters that must be considered are GVW to GCW, axle
locations, and terrain conditions.
109.62 inches raised (24 inch ground clearance) and 94.62
inches squatted (9 inch ground clearance). FTTS is 374.5
inches long and has a 96 inch width, with a 77 inch track? Note
that these dimensions are subject to change.
x
x
The FTTS-MSV from CW to GCW shall be capable of traversing a dry hard surface
side slope up to and including 30 percent. Side slope operation shall be performed
with either side of the vehicle facing up slope and without loss of stability or
malfunction
Soft Soil Traversing Characteristics. The FTTS-MSV (with companion trailer) shall
have equal or better Mobility Rating Speed (MRS) and percent GO/NO-GO than the
FCS.
The FTTS MSV and its companion trailer shall incorporate means to adjust tire
pressure to increase cross country mobility. The FTTS-MSV shall incorporate this
capability to allow the operator to adjust tire pressure.
Dimensions do not apply to the companion trailer, these are dimensions and
requirements for the FTTS prime mover. Variable height may however be required for
the trailer to meet transport requirements.
Statistics:
- Number of Requirement Paragraphs:
- Number of Stated Requirements:
- Requirements Needing Clarification:
- Number of Requirement Disconnects:
Total Requirement Issues:
135
250
20 (8%)
12 (5%)
32 (13%)
RTRM Helps To Identify & Resolve Requirement Issues
INCOSE BRIEF @ DRS Technologies
9
System N2 Diagram
• The 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
Helps To Surface Interface Issues
N2 Helps
To Identify Interface Issues
INCOSE BRIEF @ DRS Technologies
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Example 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:
GVWCWCrew
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
(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
Net-ready, C2,
FBCB2, MTS
Silent
Watch
(2 Hours)
RFID
C2 Equip
Weight
C2
Equipmen
t Weight
Antennas
15 kW OB
10 kW Exp
Exp Power
Weight
Trades
A-Kit Vs
B-Kit
Not
Specified
GVW: CW
+ Payload
+ Crew
Height
Impacts
Weight
Not
Specified
Height
Impacts
Weight
Transportability
C4ISR/EW
Obstacle
Avoidance
Elec Power
Hybrid Drive
Option
Supportability
Fuel
Efficiency
60 ton-mpg
400 mile
range
GVW
Acceleration
Curb Weight
Height
Stowage
Items
BII
13,000 lbs Max.
Axel Loading
Weight
Trades
Suspension
Health Mgt.
CBM+
Weight
Trades
13,000 lbs Max.
Axel Loading
A0=95%
MMBF=10,000
for Production
< 157.5”
for Berne
Tunnel
Analytical Hierarchy Process (AHP)
• Proven, effective means to deal with complex decision making
involving multiple criteria
• Captures both subjective and objective evaluation measures
• A hierarchal decomposition of requirements or goals is
accomplished
• Pair 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)
AHP Helps to Determine Relative Importance
INCOSE BRIEF @ DRS Technologies
12
Requirements Model Breakdown
Model
Level 1
Model
Level 2
Model
Level 3
Mobility






GVW
Driver Vision
Stability
Speed
HP/ton
Operational
Range

Fuel
efficiency
(ton-mpg)
Fuel Capacity
Armor
Protection


Transportability




CW
Height 76in
Axle Loading
30 min Ready
Survivability





CREW2.1
SD Weapon
CBRNE
Signature Mgt
Ballistics
Protection


LVOSS
Visual
signature
Thermal
signature
EM signature
Direct Fire
IED
Mine
Anti-tank
Blast
Protection
Seats
Crush
resistant roof








Model
Level 4


Power
Management
C4IRS/EW




C3
SA
Net
Security
Bus
Architect




Power Buses
OB Power
Export Power
Electrical
Storage
Supportability





RAM
Health Mgt
HFE
O&S Cost
Commonality
Payload


Flatrack
(3,200 lb)
Cargo
(22,000 lb)
Fuel
Specifics
ECU Map
Legend:
GWV =Gross Vehicle Weight, CW = Curb Weight, C3 = Command, Control, Communications, SD = Self-Defense, SA = Situational Awareness, OB = OnBoard, 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
INCOSE BRIEF @ DRS Technologies
13
Analytical Hierarchy Process Snapshot
Combinatorial 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
Driver Vision Roll Stability
Top Speed
Hp/ton
Operating Range
GVW
1
0
0
2
0
0
Drive Vision
2
1
1
2
1
2
Roll Stability
2
1
1
2
2
2
Top Speed
0
0
0
1
0
0
Hp/ton
2
1
0
2
1
1
Operating Range
2
0
0
2
1
1
Level 3 Requirements- Operating Range
Fuel Efficiency
Fuel Capacity
Fuel Efficiency
1
0
Fuel Capacity
2
1
Armor Protection
0
0
Totals
Weighting
3
9
10
1
7
6
36
Normalized
0.083
0.250
0.278
0.028
0.194
0.167
1
Global
0.012
0.035
0.039
0.004
0.027
0.023
0.140
Totals
Weighting
3
5
1
9
Normalized
0.333
0.556
0.111
1.000
Global
0.0078
0.0130
0.0026
0.023
Totals
Weighting
3
1
4
Normalized
0.750
0.250
1
Global
0.0058
0.0019
0.0078
Armor Protection
2
2
1
Level 4 Requirements- Fuel Efficiency
Fuel Specifics
ECU Map
Fuel Specifics
1
2
ECU Map
0
1
INCOSE BRIEF @ DRS Technologies
14
Quality Function Deployment (QFD)
• There are many customers
• There are stated and unstated requirements
• QFD helps to prioritize requirements and their
tradeoffs
• QFD makes invisible requirements and strategic
advantages visible
• QFD helps to define which improvements provide
the most gain
• QFD promotes Team Consensus
• QFD provides a documented audit trail for
decisions
The “House of Quality” Captures the Voice of the Customer
INCOSE BRIEF @ DRS Technologies
15
“House of Quality”
Requirements/Desires
(Voice of the Customer)
Interrelationships
between Technologies
Technologies (Voice of the Company)
Planning Matrix
-Requirements Importance
-Percent Improvement Desired
-Marketing Competition
Assessment
Relationships between
Requirements and
Technologies
Prioritized Technologies
INCOSE BRIEF @ DRS Technologies
16
Powered Trailer QFD Analysis
• Two meetings were conducted with shareholders to get
consensus on the Powered Trailer “House of Quality”
• Body of Matrix
– Common 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 associations
– Segregated positive and negative correlations,
ensured they were mutually exclusive
– Achieved Consensus, Consensus, Consensus
• QFD was finalized via (2) additional WebEx conferences
INCOSE BRIEF @ DRS Technologies
17
Powered Trailer “House of Quality”
+
-
3
9
9
9
3
1
3
3
9
3
3
3
3
9
1
3
3
9
9
3
9
3
3
9
9
9
9
3
3
3
1
3
3
1
3
1
3
3
1
1
1
1
1
1
1
1
9
1
9
3
3
3
3
3
3
3
3
3
3
3
3
3
1
1
3
1
9
3
9
3
1
3
1
1
1
Sensors
3
1
9
9
9
1
1
9
1
9
9
3
9
3
Standard serial bus
9
9
9
3
9
3
1
Auto ID Technology
9
9
9
3
Power Storage
3
1
3
Signature mgt.
Smart tie down
1
Applique armour
Configued Load SW
Cargo Tagging
Intelligent LHS
Adjustable Height deck
Steering
MIP
Dual Vs 3 Axles
Braking
Suspension
Umbilical
9
3
3
3
3
1
9
9
9
3
9
3
3
3
3
1
9
1
3
9
9
3
3
3
3
1
1
1
9
3
3
9
9
9
1
9
3
3
9
TECHNICAL DIFFICULTY(TD)
TD Normalized
COST FACTOR
Cost Factor Normalized
3
1.5
3
1.5
2
2
1
2
1.0 1.0 0.5 1.0
2
2
1
2
1.0 1.0 0.5 1.0
2
1.0
2
1.0
2
1.0
2
1.0
1
0.5
2
1.0
1
0.5
1
0.5
2
1.0
2
1.0
2
1.0
2
1.0
2
1.0
1
0.5
2
1.0
2
1.0
2
1.0
2
1.0
2
1.0
2
1.0
2
1.0
1
0.5
2
1.0
1
0.5
2
1.0
2
1.0
2
1.0
2
1.0
2
1.0
2
1.0
2
1.0
1
0.5
1
0.5
2
1.0
2
1.0
3
1.5
2
2
1.0 1.0
2
2
1.0 1.0
1
0.5
1
0.5
TECHNOLOGY PRIORITIES
PERCENTAGE OF TOTAL
504 73 95 89 354
12.7 1.9 2.4 2.2 9.0
0
0.0
90
2.3
45
1.1
39
1.0
150
3.8
469
11.8
75
1.9
237
6.0
323
8.2
125 77
3.2 2.0
110
2.8
15
0.4
33
0.8
80
2.0
11
0.3
29
0.7
489
12.4
186 197
4.7 5.0
63
1.6
Percentage of Total
9
3
9
9
3
9
9
9
9
Overall Weighting
1
1
Improvement Factor
1
9
9
3
9
3
9
3
9
3
1
3
9
9
9
3
3
PLANNING MATRIX
Customer Importance
3
1
3
9
Variable
1
Thermostat
ICE only
1
Continuous
Hybrid Propulsion
Power Mgt & Control
+
+
↑
Survivability Storage Tech.
Diagnostics/Prognostics
↑
Remote Operations Suspension Axles Steering Braking Cargo Handling
Wireless (RF)
↓
Electric PTO
Trailer
Requirements
PERFORMANCE
Maximize payload
4
Dash speed (deleted)
Minimize turning radius
3
Step up vertical obstacle
2
Fording
4
Cross trenches
3
60% longitudinal slope
4
30% side slope
4
Transportability - via surface
5
Transportability - via air
5
No mobility degradation
5
Range (fuel economy)
5
Self-charging system
2
Pwr & control from truck
3
Trailer has own brakes
5
Trailer provides export pwr
2
Enhanced survivability
2
Communicate with truck
5
"FTTS" Prime Mover Interoperability
5
9
"Current" Prime Mover Interoperability
3
9
Interface with flatracks/cargo
5
Auto self fuel
1
O&S COST RELATED
Maintenance Ratio 0.025
5
9
On-board fluid analysis
3
Embedded diag/prognostics
5
Fault isolation (deleted)
Configuration Commonality
4
3
Min.storage system maint. (deleted)
Reliability
5
9
ENVIRONMENTAL
(Temp/EMI/Vib/Shock/Corrosion)
4
9
Mechanical PTO
Customer Importance
None-towed only
↑
Propulsion
DIRECTION OF MOVEMENT
Technology Areas
4
0
3
2
4
3
4
4
5
5
5
5
2
3
5
2
2
5
5
3
5
1
1.00
0.00
1.50
1.50
1.15
1.30
1.25
1.00
1.50
1.20
2.00
1.30
1.00
1.25
1.00
1.25
1.20
1.30
1.00
1.10
1.25
1.10
4
0
4.5
3
4.6
3.9
5
4
7.5
6
10
6.5
2
3.8
5
2.5
2.4
6.5
5
3.3
6.3
1.1
3.1
0
3.5
2.3
3.6
3
3.9
3.1
5.8
4.6
7.7
5
1.5
2.9
3.9
1.9
1.9
5
3.9
2.6
4.8
0.9
5
3
5
0
4
0
5
1.40 7
1.10 3.3
1.20 6
0.00 0
1.25 5
0.00 0
1.20 6
5.4
2.6
4.6
0
3.9
0
4.6
4
1.30 5.2
4
129 100
3959
100
Powered Trailer “House of Quality”
INCOSE BRIEF @ DRS Technologies
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QFD Relative Ranking
100
90
80
70
60
50
40
30
20
10
0
QFD Relative Ranking
Suspension
ICE
Hybrid
Braking
Pwr Storage
Steering
Towed
LHS
Serial Bus
Auto ID
Adj. Deck
3 Axles
Umbilical
MIP
Elect PTO
Smart Tie
Mech PTO
Signature Mgt
Wireless
(Excludes Technical Difficulty and Cost Factors)
INCOSE BRIEF @ DRS Technologies
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Arrow’s Impossibility Theorem
(A Word of Caution!)
• Combining individual preferences to form a
group utility function presents a problem
• The use of averaged group preference data
in product design optimization can lead to
erroneous results
• This problem may not always be selfevident in the analysis of complex systems
and products
Group Consensus Must Be Reached To Avoid This Problem
Provides a Hierarchical Model For Doing Tradeoffs
INCOSE BRIEF @ DRS Technologies
21
Morphological Analysis
• Designed for multi-dimensional, nonquantifiable problem complexes
• Explores boundary conditions
• Investigates the total set of possible
relationships and “configuration” alternatives
• Rules out alternatives that are inconsistent
or incompatible using cross-consistency
assessment
MA Ensures No Alternative is Overlooked
INCOSE BRIEF @ DRS Technologies
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Morphological Field Example:
3-Parameters: color, texture, size
Color: 5 discrete values:
red, green, blue, yellow, brown
Texture: 5 discrete values:
smooth, serrated, rough, grainy,
bumpy
Size: 3 discrete values:
large, medium, small
75 cells or configurations
(Zwicky, 1969, p. 118.)
INCOSE BRIEF @ DRS Technologies
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MA-Trailer Drive Alternatives
Vehicle Output
Energy Form
Trailer Drive Type
No.
Vehicle Output
Energy Form
Trailer Drive
Consistency?
YES/NO
1
Mechanical
Mechanical
YES
2
Mechanical
Electrical
NO
Mechanical
Mechanical
Electrical
Electrical
3
Mechanical
Hydraulic
NO
4
Mechanical
ICE
NO
Hydraulic
Hydraulic
5
Electrical
Mechanical
NO
None
Internal Combustion
Engine (ICE)
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
Number of Configurations or Alternatives
4 X 6 = 24
13
None
Mechanical
NO
14
None
Electrical
NO
Ruled out Combinations of Output Energy and Hybrid
3 X 2 = 06
15
None
Hydraulic
NO
16
None
ICE
YES
17
None
Hybrid Electric
YES
18
None
Hybrid Hydraulic
YES
Hybrid Electric
Hybrid Hydraulic
18 Alternatives to Investigate→
(5) Drive Alternatives Remain in Trade Space
INCOSE BRIEF @ DRS Technologies
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Powered Trailer Design Concepts
• ALT #1 Electric PTO -Electrical Power Take Off
provided by the transport
• ALT #2 HEV -Series Hybrid Electric Vehicle with
ICE, generator, and battery pack
• ALT #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
ICE = Internal Combustion Engine
INCOSE BRIEF @ DRS Technologies
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Features Common To All Concepts
•
•
•
•
395/85 R20 XZL tires
Central Tire Inflation System (CTIS)
Pneumatic Anti-Lock Brake System (ABS)
Serial communications with transport
– Control of mobility assist and CTIS
– Receipt of trailer health and cargo load
status
• Independent Suspension
• Trailer bed basic design
INCOSE BRIEF @ DRS Technologies
26
Concepts
ALT #1 Elect PTO
ALT #2 HEV
Trailer
Trailer
200 Kw 300 vdc
mechanical
Transport
Control box/Inverter
Display
motor
System Controller DC-AC Inverter
12/24 vdc
for electronics,
trailer lights, etc.
pump
Control box/Inverter
motor
motor
Control box/Inverter
pump
12/24 vdc
for electronics,
trailer lights, etc.
radiator
Export Power
ABS
Display
System Controller DC-AC Inverter
radiator
Export Power
Operator Remote
Control Unit
Operator Remote
Control Unit
Note: Brake and CTIS lines not shown for clarity
Note: Brake and CTIS lines not shown for clarity
ALT #4 Mech PTO
ALT #3 HHV
Trailer
pneumatic
Trailer
pneumatic
Battery Pack 36 kW-hr
ICE Generator (25) 120 amp-hr batteries
Air tanks
ABS
fuel tank
Control box/Inverter
serial
CTIS
Transport
discrete
motor
CTIS
mechanical
Battery Pack 36 kW-hr
(25) 120 amp-hr batteries
Air tanks
serial
Steering actuator
discrete
Steering actuator
pneumatic
pneumatic
discrete
Pump/
motor
discrete
serial
Transport
Low pressure
reservoir
mechanical
ICE
serial
ABS
System Controller
High pressure accumulator
Display
System Controller
hydraulic
Display
12/24 vdc
for electronics,
trailer lights,etc.
12/24 vdc
for electronics,
trailer lights,etc.
Operator Remote
Control Unit
ALT #5 ICE Drive
Note: Brake and CTIS
lines to wheels not shown
for clarity
Note: Brake and CTIS
lines to wheels not shown
for clarity
Trailer
pneumatic
Generator
ICE
CVT
serial
Transport
ABS
mechanical
PTO
Display
Display
discrete
Transport
ABS
mechanical
Fuel
Tank
Display
Display
System Controller
Architectural Views for
all Five Alternatives
DC-AC Inverter
12/24 vdc
for electronics,
trailer lights,etc.
Export Power
Operator Remote
Control Unit
Note: Brake and CTIS
lines to wheels not shown
for clarity
INCOSE BRIEF @ DRS Technologies
27
Physical Characteristics
Wheel Drive
Suspension
ALT#1
Electric
PTO
ALT#2
HEV
ALT#3
HHV
ALT#4
Mech
PTO
ALT#5
ICE drive
4x2
4x4
4x2
4x2
4x4
Trailing Arm
Either Type
Either Type
Double A-Arm Double A-Arm
Length (in)
Width (in)
Deck Height (in)
Ground
Clearance (in)
Track (in)
280
96
51.5
328
96
51.5
285
96
51.5
280
96
51.5
328
96
51.5
18
81
18
81
18
79
18
81
18
81
Wheel Base (in)
Basic Bed (lbs)
192
5,745
192
5,745
201
5,745
192
5,745
192
5,745
Suspension &
Power Drive (lbs)
Flat rack (lbs)
6,625
9,800
5,155
4,875
7,570
3,200
3,200
3,200
3,200
3,200
Cargo Load (lbs)
22,000
22,000
22,000
22,000
22,000
Total Weigh-lbs
37,570
18.8 ST
40,395
20.2 ST
36,100
18.1 ST
35,820
18 ST
38,515
19.3 ST
ST = Short Ton or 2,000 lbs
INCOSE BRIEF @ DRS Technologies
28
ALT #1 Elect PTO Components
Detail Needed for Credible Cost & Schedule Estimates
INCOSE BRIEF @ DRS Technologies
29
Cost Vs Key Requirements Met
Cost Vs Key Requirements Met
$150K
HHV 85
Cost
per 1000 Units
$140K
HEV 95
$70K
ICE 85
$55K
Elec PTO 75
$40K
Mech PTO 60
$35K
Basic 45
0
10
20
30
40
50
60
70
80
90
100
Percent of Key Requirements Met
INCOSE BRIEF @ DRS Technologies
30
Comparison of Alternatives
Trade
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
Weighting/Scoring 0-5 with 5 Best
INCOSE BRIEF @ DRS Technologies
31
SE Tool Usage Summary
• Understanding requirements; their
relationships, and relative importance:
– Tools: RTRM, N2 Diagram, AHP
• Getting 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
INCOSE BRIEF @ DRS Technologies
32
Conclusions
• SE Process Critical for Providing Best Balanced
Solution
• SE Tools Assist in:
– Understanding requirements and their relationships
– Getting consensus on which technology options provide
the greatest benefits
– Assuring no viable alternative is overlooked
– Performing meaningful tradeoffs and sensitivity analysis
– Making decisions involving multiple attribute criteria
Go to: www.incose.org for more information
Capturing the Results in the Requirements Set
Reduces Program Execution Risks
INCOSE BRIEF @ DRS Technologies
33
Questions ?
INCOSE BRIEF @ DRS Technologies
34

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