Team Members:Project Leader: Stephen Visalli (ME)Randy Cicale (CE)Laurence DeWitt (EE)Stephen Ray (CE)Ian Shelley (EE)Christopher Stilson (EE)
Coordinator: Dr. Alan Nye (ME)Advisor: Dr. Mercin Lukowiak (CE)
Kate Gleason College of EngineeringJames E Gleason BuildingRochester Institute of TechnologyRochester NY, 14623-5604Attn: Stephen VisalliPhone: 315-796-5602E-mail: [email protected]
ABSTRACT:P06010 is a project involving an unmanned surveillance vehicle (USV). A
robotic vehicle, (i.e. radio controlled) will be designed and constructed. Global Positioning System (GPS) will be used to move the vehicle through waypoints on a course, while a camera takes photographic surveillance at specific locations along the route. The information provided in this package is for preliminary design review. All information and designs within this package is the sole property of the team members specified above, and is not to be used without their expressed written consent.
A summary description of what the product (project) is.
The mission of this project is to allow for an automated constant surveillance system utilizing an unmanned vehicle, GPS, and photographic feedback.
1.2 Scope Limitations
A description of what features the product shall contain and/or what constraints are placed on the project.
2.1 Cost of final design should not exceed $2000.002.2 This project is not designed to provide professional quality photographic surveillance.
2.2.1 Bit Rate shall be no higher than: 38.4kbps2.3 Streaming video will be obtained2.4 The vehicle shall not be designed for use on any surface other than dry pavement (or similar)2.5 Battery life shall be no less than one hour
1.3 Stakeholders
A list of all groups that will in some way interact with the product. These include customer, user, service personnel, sales, manufacturing and other engineering groups.
3.1 Team members3.2 Senior Design coordinator – Dr. Alan Nye3.3 Sponsors – To Be Determined (TBD)
1.4 Key Business Goals
A discussion of financial measures of success, such as profit, return on investment, payback period, net present value, etc.
4.1 Provide a sub-$2000 package for surveillance market4.2 Obtain sponsorship for parts over $200.
1.5 Financial Analysis
Detailed financial analysis that itemizes development costs, manufacturing costs, sales volume, cash flow, etc.
5.1 Private companies/institutions shall be propositioned for donation of parts and/or money due to the lack of a project sponsor5.2 Minimize cost when selecting components/materials5.3 Detailed analysis
The vehicle shall appeal to individuals or companies interested in
6
mobile security and surveillance
7
1.7 Secondary Markets
A description of other customer groups that could be reached with minor modifications of the product design.
This design should appeal to surveillance interests of the US military
1.8 Success Qualifiers
A list of critical performance parameters that make the product interesting enough for a customer to consider the product for purchase.
8.1 Technical 8.1.1 Establish communication between GPS and vehicle at 900MHz frequency with variable data rate8.1.2 Establish two way communication between vehicle and remote computer8.1.3 Provide a Graphical User Interface (GUI) program on remote computer
8.1.3.1 Shows car location8.1.3.2 Images8.1.3.3 Ability to change waypoints 8.3.1.4 Manual override
8.1.4 Determine GPS error within 2 meters8.1.5 Minimize error to within 2 meters using a best fit line of scattered data points. 8.1.6 Provide photographic feedback at a resolution of 1.2GB constantly 8.1.7 FCC limitations - none
8.2 EconomicAdhere to financial analysis as described in section 5.0
8.3 Performance Attributes8.3.1 The vehicle shall demonstrate its ability to navigate through waypoints using GPS. The course will be predetermined and will be square in shape with 90 degree turns. The distance will be less than the size of S-Lot and the vehicle speed will be approximately 3-5 mph. The vehicle will take a photograph of an item placed at each waypoint and send back to remote computer before moving to the next waypoint.8.3.2 The vehicle shall provide reliable data transfer with usabledata, where reliable indicates that all data is safely transmitted from one location to the other using standard error checking schemes.
8.4 Schedule or Time Attributes8.4.1 Concept Peer Review – Week 68.4.2 Preliminary Design Review with Report – Week 108.4.3 Prototype Completion – Week 158.4.4 Test, Debug Completion – Week 178.4.5 Comprehensive Design Review with report – Week 20
8
1.9 Success Winners
A list of critical performance parameters that are likely to lead the customer to choose your product over that of the lead competition.
9.1 The components of the vehicle should be “off-the-shelf” components, easily accessible and readily available9.2 The vehicle should be ready for sale to prospective buyers by the end of Senior Design II9.3 The team should be able to produce an additional vehicle within two weeks, given the necessary materials and components
1.10 Innovation Opportunities
Features, performance levels, and technologies in the base product design that could be significantly improved in an effort to produce significantly greater sales.
10.1 The vehicle should be designed for use on various types of surfaces (i.e. grass, sand, snow)10.2 The vehicle should be able to provide constant photographic feedback via streaming video10.3 The vehicle should be able to correct for real-time changes in GPS coordinates10.4 The vehicle should be able to correct for obstructions in its path10.5 Adapt system for use on a RC-helicopter
1.11 Formal Statement of WorkThe team shall provide one fully functional and complete USV prototype byMay 24, 2006. This prototype will fulfill the objectives as described in the Needs Assessment.
AgreedBy: Stephen Visalli: (Design Team Member)By: Randy Cicale: (Design Team Member)By: Ian Shelley: (Design Team Member)By: Steven Ray: (Design Team Member)By: Laurence DeWitt: (Design Team Member)By: Christopher Stilson: (Design Team Member)
9
2 CONCEPT DEVELOPMENT
2.1 BackgroundITT Industries was interested in being a sponsor for this project from its
conception. After the project was initiated and approved by RIT, ITT sent a revised project proposal which modified the original proposal, but in general was very similar. This new proposal was accepted by the team. During week four of RIT’s Fall Quarter, further discussions with ITT representatives resulted in their proposal of a completely new project, scrapping the current one. Project time constraints and the team’s interest in the current project resulted in ITT terminating its sponsorship with the team.
The concept development phase began with a brainstorming session, followed by discussion among the group members to narrow the objective list down to only the best ideas. Once the final selection of concepts and features had been made, assembly drawings were created.
2.2 Conceptual Level Design DrawingsIn order to visualize the USV and better assess the viability of ideas originated
during the brainstorming session, the team participated in a group-drawing session.During this session, each member began drawing his idea of the USV system.After a few minutes, the members exchanged drawings with each other and made additions to the next one.
2.3 Project DiagramAfter completing the group drawings in notebooks, a project diagram evolved. As
seen in the Project Diagram, appendix 7.1, the vehicle will have connected to it a camera system, GPS module, and a Field Programmable Gate Array (FPGA) for communication. A remote computer will be used to input the coordinates of the desired location. The current and desired locations will be interpreted using the GPS, so that the servos can be controlled. The servos will be on and off to allow movement of the vehicle in its desired direction. While this is occurring, photographic surveillance from a small camera mounted on the vehicle will record pictures, which are then sent to the remote computer station via wireless transmission.
2.4 Objective TreesAn extremely useful tool in project management is the objective tree. This gives
a better understanding of the project or various aspects of the project through a graphic approach. With this in mind, objective trees have been developed for the project’s budget, success qualifiers of the project, the control of the GPS, and the surveillance system. These are shown in appendices 7.3-7.6.
10
2.5 Quality Function Deployment (QFD)Another useful tool is the “House of Quality” or QFD model. This method
identifies the importance of each objective and specification of the project. This is the basis of our feasibility assessment, or how well a given component meets our desired specifications. It serves as a form of design criteria, and enables the listing of objectives in order of criticality. As seen in Figure 2.1, the following is a list of the design objectives in order of importance:
Order of Importance (Iteration #1):1. Price ($)2. Transmission Rate (kbps)3. Battery Life (hr)4. Steps to Input Coordinates (#)5. Speed of Vehicle (ft/sec)6. Image Quality (kb)7. (Tie) Battery Power (V), GPS Error (ft), Aesthetics of Car (%), Durability (%)8. GPS Frequency (MHz)9. Size of Assembly (LxWxH), (ft)
Revised (Iteration #2) Order of Importance:1. Price ($)2. Transmission Rate (kbps)3. Battery Life (hr)4. Steps to Input Coordinates (#)5. Speed of Vehicle (ft/sec)6. Image Quality (kb)7. Battery Power (V)8. GPS Frequency (MHz)9. GPS Error (ft)10. Size of Assembly (LxWxH), (ft^3)11. Durability (%)12. Aesthetics of Car (%)The first iteration of this QFD yielded a four-way tie for 7th place. A revised
analysis follows. After re-evaluating certain customer requirements, different values were assigned to various metrics. The Relative Importance (Room 3) is an average of the three entities: 1. Production, 2. Sales and Marketing, 3. Customer/End User. Our top priority is the metric with an Absolute Importance equal to 1.00, which is Price in dollars. Therefore our main objective is to create a system as cost efficient as possible. We also note that the next most important metric is the transmission rate of data in kbps. Obtaining a low-cost transceiver is a high priority based on these two facts. Battery life is the third most important metric, according to this method. One issue that must be addressed is that battery life and battery power are strongly related, but does this mean we can simply add more batteries to the vehicle? GPS frequency is one of the lowest in importance in this method; however, we must not ignore this because we do not want interference with other frequencies including the wireless transmission and image relay. Size of the vehicle does not seem to be a major issue at this point. It will be a factor, though when mounting components, since the camera must be able to take a picture of a
11
certain view, based on the GPS location. There must be enough room to mount everything, but not too much so that we are wasting materials, space, and creating a heavy vehicle. Aesthetics of the vehicle is the least important. We are looking for function over form. This revised list is generally agreed upon by the team members, and will be used when making design decisions as well as purchasing decisions.
12
Figure 2.1: QFD Model
13
3 Feasibility Assessment
3.1 Feasibility of the Project3.1.1 This project’s proposal meets the requirements for a RIT Multidisciplinary Engineering Design Project and has been approved by RIT ME faculty.3.1.2 This project’s timeline corresponds to that of a twenty-week-long project from conception to completion and review. See the project Gantt chart for details on this timeline.3.1.3 Since this project does not have a major sponsor, cost of components and materials will be minimized as much as possible. Private sponsorship from suppliers will be utilized as much as possible, including the Field Programmable Gate Array (FPGA). See the project financial analysis for more information.3.1.4 All of the components that will be included in the system have shown to be winners of the Pugh’s method of feasibility. By using our engineering knowledge, the team has compared various models or choices for selection. The Pugh’s method has shown to be very important as a decision tool, as the components selected in theory will work the best.3.1.5 The resources available begin with a vast knowledge of engineering curriculum, with two Computer Engineers, three Electrical Engineers, and one Mechanical Engineer.
3.2 Feasibility ProcessThe process to form a formal feasibility assessment began by answering some
general questions regarding the technical, economic, market, scheduling, and performance feasibility of each design. Each design was assigned a rating between 0 and 5 for each of the questions. This rating represents the feasibility of the design with respect to the question posed. A base model design was given a rating of 3.0 for each question, on which the other designs were based on. A rating of zero means that the design is much worse than the base model, while a five signifies that the design is much better than the base model. This is the basis of Pugh’s Analysis of Feasibility. The “expert” responsible for a given component completed the Pugh’s method, which then was reviewed by the remaining team members. The following section presents the questions by which the concepts were judged, as well as explanations of the ratings the team assigned to the components
3.3 Feasibility Analysis for Components3.3.1 Base-plate
The base plate must be light, yet strong enough to allow mounting of the various components. A thin 1/8” sheet of aluminum is ideal, though high pricing
14
of raw materials may force us to use steel. This sheet-metal can be shaped and finished using RIT facilities and tooling, which will be performed by the team Mechanical Engineer. See Figure 3.10-3.12 for Finite Element Analysis (FEA) for deflection and stress using ANSYS™ software.
Figure 3.1: Pugh’s Method – Base-plate
3.3.2 Drive-train The drive-train must be free of as much energy loss as possible, therefore the lower the number of linkages or mechanisms present, the better. For this reason, the chain-driven system was not feasible. There would be too many moving parts, increasing cost, complexity, and reducing performance. See figure 3.2 for Pugh’s method of feasibility.
Evaluate each additional concept against the baseline, score each
attribute as: 1 = much worse than baseline
concept 2 = worse than baseline 3 = same as
baseline 4 = better than baseline 5= much better
than baselineAl
umin
umAl
umin
um
Stee
lSt
eel
Com
posit
eCo
mpo
site
Woo
dW
ood
Material Availability?Material Availability? 3.0 3 1 4 Strength?Strength? 3.0 3 4 1 Finish?Finish? 3.0 2 4 2 Easy to process?Easy to process? 3.0 3 2 4 Time to process?Time to process? 3.0 3 2 3 Aesthetic appeal?Aesthetic appeal? 3.0 2 5 1 Cost of material?Cost of material? 3.0 4 1 5 Mean ScoreMean Score 3.0 2.9 2.7 2.9
Normalized ScoreNormalized Score100.0
%95.2
%90.5
%95.2
%
15
Figure 3.2: Pugh’s Method – Drive TrainEvaluate each additional
concept against the baseline, score each attribute as: 1 = much worse than baseline
concept 2 = worse than baseline 3 = same as baseline 4 = better than baseline 5= much
better than baseline 1 se
rvo
for e
ach
1 se
rvo
for e
ach
whee
lwh
eel
2 se
rvos
, opp
osite
2 se
rvos
, opp
osite
co
rner
sco
rner
s
2 se
rvos
, Cha
in2
serv
os, C
hain
Dr
iven
Driv
en
2 se
rvos
, Bel
t2
serv
os, B
elt
Driv
enDr
iven
2 Se
rvos
, 22
Serv
os, 2
ca
ster
sca
ster
s
Skill to manufacture?Skill to manufacture? 3.0 3 1 1 3 Access to necessary tooling?Access to necessary tooling? 3.0 3 2 2 3 Cost of Materials?Cost of Materials? 3.0 2 2 2 3 Cost of Purchased Components?Cost of Purchased Components? 3.0 4 3 3 3 Time to assemble?Time to assemble? 3.0 4 2 2 3 Time to order parts?Time to order parts? 3.0 3 2 2 3 Time to manufacture parts?Time to manufacture parts? 3.0 2 2 2 3 Multiple Technologies Needed?Multiple Technologies Needed? 3.0 3 3 3 3 Back-up with engineering Back-up with engineering calculations?calculations? 3.0 2 1 2 3 Performance?Performance? 3.0 2 2 2 1 Ability to be used on various Ability to be used on various surfaces?surfaces? 3.0 2 3 3 1 Mean ScoreMean Score 3.0 2.7 2.1 2.2 2.6
Normalized ScoreNormalized Score100.0
%90.9
%69.7
%72.7
%87.9
%
3.3.3 CameraAfter deciding to use a CMOS camera, the type of camera to be used had
to be considered. The obvious choice was to go with some type of wireless since we do not want any type of cable running off our vehicle. First was whether we would want to have a still camera or a video camera. Once we made that decision I made a Pugh’s Method chart to see which wireless video camera would be the best for our use. It can be seen in Figure 3.3. After comparing the units, the one that showed the best results was the CMOS color 1/3”, camera (Part Number: CM1201).
16
Figure 3.3: Pugh’s Method – Camera
Evaluate each additional concept against the baseline, score each attribute as: 1 = much worse than baseline
concept 2 = worse than baseline 3 = same as baseline 4 = better than baseline 5= much
better than baseline CMOS
B/W
(1/4
")CM
OS B
/W(1
/4")
CMOS
Col
or (1
/3")
CMOS
Col
or (1
/3")
CMOS
B/W
(1/2
")CM
OS B
/W (1
/2")
B/W
CCD
B/W
CCD
High
Pow
erHi
gh P
ower
Distance rangeDistance range 3.0 3 3 1 3 Battery needBattery need 3.0 3 3 2 2 Color cameraColor camera 1.0 3 1 1 3 Cost of Purchased Components?Cost of Purchased Components? 4.0 3 2 1 1 SizeSize 3.0 3 3 3 2 Different channelsDifferent channels 3.0 3 3 5 5 ResolutionResolution 3.0 3 3 4 4 Deg of viewing angleDeg of viewing angle 3.0 3 3 3 3 Additional 1 (Future Use)Additional 1 (Future Use) Additional 2 (Future Use)Additional 2 (Future Use) Mean ScoreMean Score 2.9 3.0 2.6 2.5 2.9
Normalized ScoreNormalized Score95.8
%100.0
%87.5
%83.3
%95.8
%
3.3.4 Global Positioning System (GPS)After deciding to use GPS, the type of receiver to be used had to be
considered. We could either use a handheld commercial model or a GPS module. Considering the price of commercial models and the difficulty associated with interpreting the data, it was determined that using a model would be the best solution. With a module, we can process the data either through RS-232 or TTL logic. After a quick internet search, several possible GPS modules were found. In order to determine the best model to use, a Pugh’s Method chart was constructed. It can be seen in Figure 3.4. After comparing the units, the one that showed the best results was the Polstar Technologies PMB-248.
17
Figure 3.4: Pugh’s Method – GPS
Evaluate each additional concept against the baseline, score each attribute as: 1 = much worse than baseline
concept 2 = worse than baseline 3 = same as baseline 4 = better than baseline 5= much
better than baseline
PMB-
248
PMB-
248
PMB-
238
PMB-
238
EM-4
01EM
-401
PGM
-102
PGM
-102
Sufficient Skills?Sufficient Skills? 3.0 3 3 3 Sufficient Software?Sufficient Software? 3.0 3 3 3 Ease of UseEase of Use 3.0 2 2 2 Cost of Materials?Cost of Materials? 3.0 3 3 3 Cost of Device?Cost of Device? 3.0 3 2 2 SizeSize 3.0 3 2 3 Integrate into system?Integrate into system? 3.0 2 1 2 AccuracyAccuracy 3.0 3 1 1 Acquisition TimeAcquisition Time 3.0 3 1 2 Power SupplyPower Supply 3.0 3 2 3 Mean ScoreMean Score 3.0 2.8 2.0 2.4
Normalized ScoreNormalized Score100.0
%93.3
%66.7
%80.0
%
3.3.5 Field Programmable Gate Array (FPGA)Since Eastman Kodak offered to provide the team with a Virtex 4 FPGA,
each device in that family was compared, and a Pugh’s Method chart was constructed. It can be seen on the next page titled “Table 1: FPGA Pugh’s Method”. After comparing the different devices the ML403 showed the best results.
18
Figure 3.5: Pugh’s Method – FPGAEvaluate each additional
concept against the baseline, score each
attribute as: 1 = much worse than baseline concept 2 = worse than baseline 3 =
same as baseline 4 = better than baseline 5= much
better than baseline Virte
x 4M
L401
Evu
alVi
rtex
4ML4
01 E
vual
Ki
tKi
t
HC12
Micr
ocon
trolle
rHC
12 M
icroc
ontro
ller
Virte
x 4
ML4
02 E
vual
Virte
x 4
ML4
02 E
vual
Ki
tKi
t
Virte
x 4
ML4
03 E
vual
Virte
x 4
ML4
03 E
vual
Ki
tKi
t
6800
068
000
Mirc
oCon
trolle
rM
ircoC
ontro
ller
Sufficient Student Skills?Sufficient Student Skills? 3.0 2 3 3 3 Processing PowerProcessing Power 3.0 2 2.5 5 2 MemoryMemory 3.0 1 3 5 1 Available LogicAvailable Logic 3.0 2 2.5 2.7 1 I/O PortsI/O Ports 3.0 1 3 3 1 Interface with extra memoryInterface with extra memory 3.0 1 3 3 1 Simulation of ModelsSimulation of Models 3.0 1 3 3 1 Cool Technology for Excitement?Cool Technology for Excitement? 3.0 1 3 4 1 CostCost 3.0 2 3 3 2 Cost of ComponentsCost of Components 3.0 1 3 3 1 Mean ScoreMean Score 3.0 1.4 2.9 3.5 1.4
Normalized ScoreNormalized Score100.0
%46.7
%96.7
%115.7
%46.7
%
3.3.6 TransceiverMost transceivers are chips only, and require an antenna, impedance
matching, memory if full duplexing is not available, power supplies, and data communication. I/O ports are not explicitly available and useful data is not directly available. The table below shows some parameters of popular wireless protocols.
Table 3.1: Parameter Comparison of Various Wireless ProtocolsWi232 Zigbee WiFi
Freq 902-928 MHz 902 MHz or 2.4 GHz 2.4 GHzOutdoor Range 4000 ft 500 ft 300-500 ftIndoor Range 400 ft 30-60 ft 50-75 ft
Evaluate each additional concept against the baseline, score each attribute as: 1 = much worse than baseline
concept 2 = worse than baseline 3 = same as baseline 4 = better than baseline 5= much
better than baseline Wi2
32 D
evel
opm
ent
Wi2
32 D
evel
opm
ent
Kit
Kit
Wi2
32W
i232
Zigb
eeZi
gbee
WiF
iW
iFi
Blue
Too
thBl
ue T
ooth
Sufficient Student Skills?Sufficient Student Skills? 3.0 1 1 1 1 Wireless Transmission DistanceWireless Transmission Distance 3.0 3 2 2 1 Power PerformancePower Performance 3.0 3 1 2 2 I/O PortsI/O Ports 3.0 2 2 2 2 CostCost 3.0 2 2 2 2 Useful Raw Data ExtractionUseful Raw Data Extraction 3.0 2 2 2 2 AvailabilityAvailability 3.0 3 0 2 2 Data RateData Rate 3.0 3 2 5 2 Development TimeDevelopment Time 3.0 2 2 2 2 Mean ScoreMean Score 3.0 2.3 1.6 2.2 1.8
Normalized ScoreNormalized Score100.0
%77.8
%51.9
%74.1
%59.3
%
3.3.7 Servo MotorsMotors play a key role in this project. They will be the components that
drive and steer the vehicle along its predetermined course. The theory behind a motor is rather simplistic when looked at broadly. Simply, the motor transfers electrical energy to mechanical energy. A controlled voltage will be applied to the motor to spin it in a certain direction and speed. A positive voltage spins the motor in a forward direction while a negative voltage will spin the motor in a reverse direction. Also note that the higher the voltage sent to the motor, the faster it will spin. This vehicle will require the use of 4 strategically selected motors
20
Many factors need to be considered when selecting a motor. The most important is that the motor is powerful enough to move the vehicle. Any motor that does not meet the required torque specification was immediately eliminated from the running. The next concern is power consumption and efficiency. The more power that is required, the more sources that need to be added to the vehicle increasing weight which will then require more torque. To avoid this potentially never-ending cycle, we will only consider the most efficient motors and take the required voltage into consideration. Voltage and torque have a direct relationship when it comes to motors, so the small size of the vehicle ensures that we will, in fact, not need high-output motors.
Figure 3.7: Pugh’s Method – Servo Motors
Evaluate each additional concept against the baseline, score each
attribute as: 1 = much worse than baseline concept 2 = worse than
baseline 3 = same as baseline 4 = better than baseline 5= much better
3.3.8 WheelsWheels are extremely important in the operation of this project. They are, in
some way, used in nearly every vehicle that moves across land. The availability of wheels is infinite and abundant with varying diameters, widths, and tread patterns.
Initially there was only one concern when selecting a wheel and that was diameter. The bigger the wheel, the faster the vehicle would move and the more clearance it would have. This remains the main concentration, but others need to be considered.
Large wheel diameter allows for the vehicle to overcome small obstacles, such as rocks, on the parking lot surface. We don’t need much clearance, but with a 5” tall tire, we have enough to clear small rocks and objects on the surface. Also, as the wheel gets
21
bigger, the vehicle will move faster. A 5” tire will yield about 5mph at 263RPM at the motor.
Tire width is important for traction and accuracy. We want a wide tire so that the vehicle is not pushed or guided off course by irregularities in the pavement surface such as cracks and height changes. The tire we will be using is 2.25” wide.
Tread pattern played a small role in wheel selection, but it just so happened that one of the best wheels we found has a very aggressive tread pattern. This will increase traction even when the rotational torque on the wheels is at its highest.
Figure 3.8: Pugh’s Method - Wheel
Evaluate each additional concept against the baseline, score each attribute as: 1 =
much worse than baseline concept 2 = worse than baseline 3 = same as
baseline 4 = better than baseline 5= much better than baseline
The information below summarizes the various characteristics of the device: Diameter = 5.0" Width = 2.25" Weight = 5.10 oz. Hubs = 6mm (HUB-05) Motor = Any 6mm output shaft (GHM-01 thru -04)
3.4 Pugh’s Method vs. Weighted MethodPugh’s method is a good way to compare a set of concepts or components. The
weighted method takes this type of analysis and also takes into account the individual design specifications by weighting them. In general, the weighted method produced similar results compared to the Pugh’s method. The camera produced almost identical results, so we will move forward with the CM1201 camera unit. The drive-train analysis also proved very similar, so we will have one servo motor for each wheel. The weighted method also confirms the use of the PMB-248 GPS board; again, it is very close to the Pugh’s method. Adding the weighted aspect to the transceiver proved that Zig-Bee, Bluetooth, and WiFi are poor choices. The clear winner in this component category is the Wi232 Development Kit. As for the base-plate, aluminum is our winner, since it is strong, readily available, and easy to process. Its only drawback is the price per pound of aluminum compared to that of steel or wood. Clearly a composite would be a poor choice since it is not readily available, and is expensive. Having both methods of analysis enables us to confirm, or question the feasibility of a certain component or design concept. We will continue to use this information when purchasing the components and creating our prototype.
3.5 Major Project RisksThe following is a list of possible major project risks. All will be or have been
analyzed to determine further if they pose a significant risk to the project outcome.1. Regulations: There are no FCC-related limitations or approvals needed for this design. All parts with communication aspects are “off-the-shelf”. 2. Safety: S-Lot on the RIT campus will be reserved through Campus Safety before commencing with testing of the vehicle. Proper safety equipment (i.e. cones, caution tape) will be utilized when testing the vehicle.3. Health: Proper precautions will be enforced during the fabrication, assembly and testing of the vehicle. This includes observing proper techniques and guidelines of the shop when machining the base-plate. 4. Economic: Running over-budget is a major risk. Risks associated with the destruction of system components, or the entire system is credible. A backup plan should be devised in the event that total destruction has occurred before testing has completed. How will purchases be made for needed supplies? A purchase request form will accompany discussion with the team members. Before any components are purchased, the team must agree democratically to make the purchase.5. Technical Questions: What is the preferred language for the software correction algorithms? Is there any flexibility in the sensor measurement requirements? Are there any weight requirements that need to be considered? Are there any temperature requirements that need to be considered? Are there any force or vibration requirements that need to be considered? Should the USV be designed to account for future generations with onboard data acquisition and processing capabilities (i.e. space requirements for additional hardware)? Is there a power supply limitation that needs to be accounted for when designing the USV?
3.6 Finite Element AnalysisA finite element analysis was conducted of the base-plate using ANSYS™ FEA
software. After modeling the base-plate, the four corners were constrained in all degrees of freedom, representing each of the four wheels. Since the wheels will connect to the shafts on the servo motors, and the motors will be fastened to the plate, the simplified model is a credible approximation. A total estimated force on the base-plate of 20 lbf was used in loading the plate. This was estimated from the sum of the weights of each component that will be attached to the vehicle, and includes a factor of safety of two. The weight of the circuit boards and hardware is minimal, even negligible. The majority of the weight of the vehicle (not including wheels) will be from the battery packs. The material determined most feasible for the base-plate is aluminum, and a piece has been located locally for purchase, in the form of an alloy 5052. This has a modulus of elasticity of 10.2x10^6 psi and a Poisson’s Ratio of 0.33. The analysis resulted in a Von Mises stress of 28.8 ksi and a shear stress of 14.3 ksi. Also, the resulting displacement is only 0.034 inches. This confirms that our thin sheet of aluminum will easily hold up under even the most extreme of load conditions. ANSYS™ plots are shown below.
24
Figure 3.10: ANSYS FEA – Deflection
25
Figure 3.11: ANSYS FEA – Von Mises Stress
26
Figure 3.12: ANSYS FEA – Shear Stress
27
28
4 Preliminary Design
4.1 Camera4.1.1 Background
Digital cameras have become extremely common as the prices have come down. One of the drivers behind the falling prices has been the introduction of CMOS image sensors. CMOS sensors are much less expensive to manufacture than CCD sensors.
Both CCD (charge-coupled device) and CMOS (complimentary metal-oxide semiconductor) image sensors start at the same point -- they have to convert light into electrons. One simplified way to think about the sensor used in a digital camera is to think of it as having a 2-D array of thousands or millions of tiny solar cells, each of which transforms the light from one small portion of the image into electrons. Both CCD and CMOS devices perform this task using a variety of technologies.
The next step is to read the value (accumulated charge) of each cell in the image. In a CCD device, the charge is actually transported across the chip and read at one corner of the array. An analog-to-digital converter turns each pixel's value into a digital value. In most CMOS devices, there are several transistors at each pixel that amplify and move the charge using more traditional wires. The CMOS approach is more flexible because each pixel can be read individually.
CCDs use a special manufacturing process to create the ability to transport charge across the chip without distortion. This process leads to very high-quality sensors in terms of fidelity and light sensitivity. CMOS chips, on the other hand, use traditional manufacturing processes to create the chip. Because of the manufacturing differences, there have been some noticeable differences between CCD and CMOS sensors. CCD sensors, as mentioned above, create high-quality, low-noise images.
CMOS sensors, traditionally, are more susceptible to noise. Because each pixel on a CMOS sensor has several transistors located next to
it, the light sensitivity of a CMOS chip tends to be lower. Many of the photons hitting the chip hit the transistors instead of the photodiode.
CMOS traditionally consumes little power. Implementing a sensor in CMOS yields a low-power sensor.
CCDs use a process that consumes lots of power. CCDs consume as much as 100 times more power than an equivalent CMOS sensor.
CMOS chips can be fabricated on just about any standard silicon production line, so they tend to be extremely inexpensive compared to CCD sensors.
CCD sensors have been mass produced for a longer period of time, so they are more mature. They tend to have higher quality and more pixels.
Based on these differences, you can see that CCDs tend to be used in cameras that focus on high-quality images with lots of pixels and excellent light sensitivity. CMOS sensors traditionally have lower quality, lower resolution and lower sensitivity. CMOS sensors are just now improving to the point where they
29
reach near parity with CCD devices in some applications. CMOS cameras are usually less expensive and have great battery life.
4.1.2 SpecificationsCM-1201 series cameras are worlds smallest yet most powerful wireless
camera of its kind. New high power 1.2 GHz technology provides 1000ft range of transmission with solid stability and will not be interfered by crowded 2.4GHz signals. Great for portable video surveillance or for hobbies. The camera and the built-in transmitter only uses about 150mA of power and operates for up to 8 hours on 9 V battery.
Listed Specs:CM-1201: (Color) - Up to 1000 feet ( Clear line of sight )- Resolution: Color, 5 Lux, 330 TV line- 9V DC, 150mA (lasts up to 8 hours on 9V batt)- 0.8" x 0.8"x .75"- Viewing angle: 60 deg- Includes base station
The key feature of this camera is that it can be completely separate from the design itself. It can operate on its own battery, wireless connection and receiver. All we will need to do is plug it in to our computer to take still captures. It makes something that could have been very difficult to integrate very easy to do so.
4.2 Global Positioning System (GPS)The Global Positioning System (GPS) unit is an integral part of our
project. By using this technology we can construct a vehicle that can navigate an area automatically. GPS is a constellation of 27 Earth-orbiting satellites (24 in operation and three extras in case one fails). The U.S. military developed and implemented this satellite network as a military navigation system, but soon opened it up to everybody else. A GPS receiver's job is to locate four or more of these satellites, figure out the distance to each, and use this information to deduce its own location. This operation is based on a simple mathematical principle called tri-lateration. Tri-lateration is accomplished by knowing the distance from the GPS unit to a few satellites orbiting the Earth. The GPS receiver figures this distance by analyzing high-frequency, low-power radio signals from the GPS satellites. Better units have multiple receivers, so they can pick up signals from several satellites simultaneously.
30
Figure 4.1: GPS Satellites
4.2.1 Selecting a GPS Module
After deciding to use GPS, the type of receiver to be used had to be considered. We could either use a handheld commercial model or a GPS module. Considering the price of commercial models and the difficulty associated with interpreting the data, it was determined that using a model would be the best solution. With a module, we can process the data either through RS-232 or TTL logic. After a quick internet search, several possible GPS modules were found. In order to determine the best model to use, a Pugh’s Method chart was constructed. It can be seen on the next page titled “Table 1 – GPS Pugh’s Method”. After comparing the units, the one that showed the best results was the Polstar Technologies PMB-248.
4.2.2 Polstar Technologies PMB-248
The information below summarizes the various characteristics of the device.
PMB-248 High Sensitivity GPS Receiver Module with 12 Parallel Satellite-Tracking Channels Key Specifications/Special Features:
Characteristics o Built-in Sony's 4th generation CXD2951 GA-4 dedicated single chip for
31
GPS o Built-in WAAS/EGNOS demodulator o 12 parallel satellite-tracking channels for fast acquisition and
reacquisition o Low power consumption and ultra mini size (32 x 32mm) o Built-in rechargeable battery for memory and RTC backup o Supports NMEA 0183 V2.2 data protocol o Enhanced algorithms providing o superior navigation performance in urban, canyon and foliage
environments o For car navigation, marine navigation, fleet management, o AVL and location-based services, auto pilot, personal navigation or
touring devices, tracking devices/systems and mapping devices o Optional: 1PPS output (Hardware setting)
Properties: o Receiver: tacking up to 12 satellites, L1, 1575MHz, C/A code o Accuracy:
Position: two DRMS approximately 2m, WAAS support Velocity: 0.1m/second without SA imposed Time: +/-1u second
o Acquisition time: Cold start: 40 seconds (average) Warm start: 33 seconds (average) Hot start: 2 seconds (minimum)
o Sensitivity: Acquisition: -139dBm Tracking: -152dBm
o Dynamics: Altitude: 18,000 (maximu) Velocity: 500m/sec ond (maximum) Acceleration: +/-4g (maximum)
o Navigation update rate: once per second o Serial port: RS-232 and TTL output o Baud rate: 4800bps (9600bps, 19200bps, 38400bps optional) o Output message: NMEA 0183 V2.2 GGA, GSV, GSA, RMC (VTG,
GLL optional) o Datum: WGS 84 o Power supply: DC 5V +/- 5% o Power consumption (typical): 80mA at 5V o LED function: power on/off and navigation o Operating temperature: -10 to +70 degrees Celsius o Storage temperature: -40 to +100 o degrees Celsius o Humidity: 5% to 95% o Antenna type: built-in patch antenna
32
Main Export Markets: Worldwide
Primary Competitive Advantages: Packaging Price Product Features Product Performance Prompt Delivery Quality Approvals Reputation Service Small Orders Accepted
What makes this unit particularly useful is that it has 12 parallel satellites-tracking channels. In the explanation of how GPS works, it was explained with 4 satellites. The more that is added the more precise the values will be. This unit also has very low power consumption and is very small for its capabilities. This is particularly important when considering the size of the vehicle should not be very large. The PMB-248 is accurate up to 2 meters of the actual location which is one of the best of the non-military grade units. We have decided to use a location smaller than the size of the S parking lot, but large enough so that 2 meters will not significantly affect the vehicles abilities to navigate through the course. Another important aspect of this module is the acquisition time. The quicker it can acquire the location, the better and more efficient the vehicle can work. If the chip has been active for awhile, shutdown, and then turned back on, it could calculate the GPS position in 2 seconds. The PMB-248 was also chosen because it has both TTL and RS-232 outputs which are easy to work with. The outputs of the GPS unit will be inputted to the FPGA and then the data will be processed. Based on the coordinates, we can adjust the motors of the vehicle and travel in a certain direction. If the current GPS location is further from the desired GPS location, then the motors will be adjusted again to go in a newer educated direction.
4.3 FPGAFPGA Evaluation Board – Virtex 4 ML403
The Field Programmable Gate Arrays (FPGA) unit is a key component to our project. An FPGA is a semiconductor device containing programmable logic components and programmable interconnects. The programmable logic components when programmed duplicate the functionality of basic logic gates (and, or, for, and not), or more complex structures ranging from simple combinational functions to complex state machines. Due to the structure of the programmable interconnects; allow the logic blocks of the FPGA to be connected in any why that is needed by the designer. So in effect the FPGA is a one-chip programmable breadboard.
33
Figure 4.2: Un-segmented FPGA Routing
34
Figure 4.3: Switch Block Topology
However FPGAs tend to be slower then the application-specific integrated circuit counterparts, and are unable to handle the most complex designs, and draw more power. In order to program the FPGA, first a hardware description language (HDL) design is made. Once the design is made, it is then compiled into a netlist. The netlist is then fitted to the actual FPGA architecture, using a process called place and route. The final step takes the result from the place and route process to configure the FPGA.
Figure 4.4: Programmable logic design process
After deciding to use an FPGA, the type of FPGA kit to be used had to be considered. Since FPGA chips come ball grid array surface mount packages a Printed Circuit Board (PCB) would have to be made. Since making a PCB would exceed the project budget and time allowance an FPGA evaluation kit was the best solution.
35
Figure 4.5: Ball Grid Array Package
Figure 4.6: ML403
36
Table 4.1: SpecificationsDevice Family Support Virtex-4 FX
Key Features Xilinx Devices: XC4VFX12-FF668-10C
Vitex-4 FX12 12,312 Logic Cells 36 Block RAM/FIFO w/ECC (18 kbits each) 648 Total Block RAM (kbits) 4 Digital Clock Managers (DCM) 160 Max Differential I/O Pairs 32 XtremeDSP™ Slices 1 PowerPC Processor Blocks 2 10/100/1000 Ethernet MAC Blocks 5,017,088 Configuration Memory Bits 320 Max SelectIO
IIC EEPROM Connectors and Interfaces: 4 SMA Connectors (Differential
Clocks), 2 PS/2 Connectors (Keyboard/Mouse), 2 Audio (In/Out, Microphone/Head Phone), RS-232 Serial Port, 3 USB Ports (2 Peripheral/1 Host), PC4 JTAG, DB 15 VGA Display, 10/100/1000 RJ-45 Ethernet Port, 64 Bit User Expansion Connector, General Purpose I/O: Buttons and LEDs
Display: 16 x2 Character LCDTargeted Application Markets: Industrial, Telecom/Datacom, Medical,
Military/Aerospace Applications: Data Transmission and Manipulation, Digital
Video, Embedded Microprocessor, Bus Interface, High Speed Design, Telecom/Datacom
What makes the ML403 kit useful, is that it contains a PowerPC core inside the FPGA. Having the PowerPC core in the FPGA makes this FPGA better for embedded micro processing, data transmission and manipulation, and bus interfacing. Building the PowerPC core into the FPGA came at the price that there is less open logic available in this device. However the available logic will be more then enough to meet the needs of this project.
37
Figure 4.7: Feature set for the Virtex 4 family
4.4 TransceiverA Transceiver is a device capable of both transmitting and receiving data
wirelessly. Being a transceiver and having this dual capability, cross communication can be made between two stations.
Numerous parameters determine what type of wireless device is necessary for a given application. Duplexing is one such parameter; this is the ability of the device to transmit and receive data at the same time. The Baud Rate is the rate at which data is transmitted. Power performance is also a very important factor when dealing with wireless communication; it is very dependent on the implementation.
The wireless communication of the vehicle is one of the integral parts of this project. Therefore, the parameters of the wireless solution is paramount. The protocol must match or exceed the specifications of the project to ensure ease and accuracy of operation.
The figure below is the Wi232 transceiver board, but also demonstrates a typical transceiver board.
Figure 4.8: Wi.232 Transceiver Board
Many of the protocols are similar as far as implementation, useful data, and student skills are concerned. This project’s specifications greatly determine which protocol is to be used.
38
Blue Tooth can first be eliminated because it only transmits past about 10 ft. This project needs at the very least 500 ft of reliable transmission. WiFi and Zigbee therefore do not have the best transmissions either since at best they transmit up to 500 ft.
The Wi232 solution transmits well beyond 1000 ft outdoors and is therefore a very attractive protocol. The Wi232 is mostly equivalent to the other solutions in most parameters, but the manufacturer produces an engineering development kit. This kit is the chosen device for the project because of its ease of development. Largely most important deciding factor is that the development kit already includes RS232 and USB I/O ports as well as computer software. The board also includes an impedance matched antenna with proper power levels already established. This development board takes all the busy work out of the transceiver design and allows the team to concentrate on the true design of the project.
The Wi232 development kit is seen in the figure below.
Figure 4.9: Wi.232 Transceiver Development Board1 – Antenna2- Transceiver Board3 – RS232 Connector4 – USB Connector5 – Power Supply
39
6 – Development BoardThe various transceiver solutions are very similar in nature, but certain
parameters such as I/O ports, transmission range, and power performance spread the field.
The Wi232 solution is selected for two major reasons: data range and development time/student skills. The Baud Rate in this case is sufficient and therefore not a huge disadvantage. The transmission distance allows for flexibility in the project’s GPS analysis while the development board takes care of all the intermediate steps that are not a large part of the project’s goals.
4.5 Servo MotorsFigure 4.10: Servo Motor
The information below summarizes the various characteristics of the device. Weight = 9.92 oz Reduction = 19:1 Stall Torque = 225.64 oz-in Length (motor and gear) = 87.37mm Length (shaft only) = 19.30mm Diameter (shaft) = 6.0mm Outside Diameter = 36.0mm Current (at 12v no load) = 380mA Current (at 12v locked shaft) = 3.8A
There will be four of these motors driving the vehicle providing ample torque to move the vehicle from a stop, up hills, and while turning. The wheels used will be 2.5” in diameter yielding a top speed of roughly 2mph.
4.6 Drive-train DesignThe drive-train will consist of four servo motors, one for each wheel.
These motors will be coupled with a wheel designed to fit on the motor’s shaft. Before selecting the motor, a few calculations had to be made. The minimum necessary torque on the shaft had to be determined, to ensure that the vehicle would move forward. Also, once a motor was selected with the above calculation in mind, we checked to make sure we weren’t spending too much money on a motor that is much more powerful than necessary.
Some assumptions were made in these calculations, which have been taken into account when selecting the servo motor and wheel set up. First, the vehicle is assumed to be on level ground, although, the vehicle will be used in S-Lot of RIT, which has a gradual slope to it. Second, the calculations include a friction force between a vehicle tire and asphalt. Third, the asphalt is dry. When testing, we will make every effort to test on dry pavement. Fourth, the vehicle weight of 20 lbs is an over-estimate, yet allowing for a factor of safety. In this case, a factor of safety would allow the vehicle to travel faster, and keep the motors from burning out.
Figure 4.11: Calculating Torque on a Rotating ShaftSource: http://pergatory.mit.edu/2.007/Resources/calculations/motorcalc/motorcalc.html#torque
From the figure above, we calculate the minimum torque necessary to overcome rolling resistance as 4.5 in-lb per motor. The first servo motor examined is a 12Vdc motor with a stall-torque (max) of 14.10 in-lb. This is more than enough to power the vehicle, using the theory described above.
This Bill of Materials is preliminary, and is subject to change. Suppliers may change if the same item is found to be cheaper at a supplier other than what is listed. Assembly numbers are shown, based on the part number of the first item included. For example, A20 is the servo-motor assembly, which is part 20. Subsequent parts in the assembly are numbered appropriately, to keep the assembly in the 20-29 sub-set. The retail price and “our” price are both present so that we can keep track of how much money will be spent out of pocket, as well as the overall cost of the package. Although the raw material for the base-plate will be purchased, the finished product will be manufactured in-house.
6.0 Schedule and Gantt Chart
The Gantt chart below shows how concurrent engineering took place throughout the first 10 weeks of design. This enabled us to be more efficient by multi-tasking to accomplish milestones. The Peer Review of week six provided feedback that was analyzed, and resulted in a few minor specification and documentation revisions, but no major design changes.
Planning for the rest of the project has been initiated, with milestones outlined. We will begin the process of ordering certain parts on 11/14/05, and will continue to do so as suppliers on the BOM become agreed on by the team. The team will continue to work on the vehicle throughout the winter quarter, in effort to develop the prototype by 4/2/06. Testing and debugging will commence at this point, and is scheduled to be completed by 4/30/06. Necessary changes and finishing touches will be made in order to be fully prepared for the Comprehensive Design Review by 5/15/06.
43
Figure 6.1: Gantt Chart
44
45
7 Appendices
7.1 Project Diagram
46
7.2 Program Flowchart
47
7.3: Objective Tree: Financial Analysis
Financial Analysis
Electrical Computer and Communication
Expense (Approx.)Mechanical
Servo Motors (4)
$200.00
Camera Unit $100.00
GPS Board$30.00
Baseplate$20.00
FPGA$500.00
Wheels$20.00
Transceiver Unit
$200.00
Hardware/Other$15.00
Wiring/Other$20.00
Laptop Computer$1000.00
48
7.4 Objective Tree: GPS System
Control Vehicle Using GPS
Activate Servo Motors Transfer and Receive
GPS Data
Report in GUI
Manually Override Vehicle
End RunChange Vehicle
DirectionInterpret GPS Coordinates
Input GPS Coordinates
Input New GPS Coordinates
GUI
GUI
Button on GUI
Transceiver
Field Programmable Gate Array (FPGA)
49
7.5 Objective Tree: Success Qualifiers
50
Success Qualifiers
Technical Performance Schedule/Time Attributes
Communication with GPS at 900 MHz
Two way communication with variable data rate
Graphical User Interface (GUI)
Navigate through 4 waypoints in parking lot
Photograph correct image at each waypoint
Repeatability – Navigate Course 3X
Concept Peer Review – Week 6
Preliminary Design Review with report – Week 10
Test, Debug Completion – Week 17
Comprehensive Design Review with report – Week 20
GPS Error Definition
Vehicle Location Display Change Waypoints
Image Depiction Window Manual Override Button
Photographic data relay at 1.2GB resolution
Data Transferred Securely
GPS Error Correction
Prototype Completion – Week 15
Video/Photographic Surveillance
Communication with Camera
Display Picture/Video on Laptop
Compress Image
Transmit Image
TransceiverField Programmable Gate Array
(FPGA)Laptop
Computer
GUI
7.6 Objective Tree: Surveillance
51
7.7 Weighted Method – Camera
Evaluate each additional concept against the baseline, score each
attribute as: 1 = much worse than baseline concept 2 = worse than
baseline 3 = same as baseline 4 = better than baseline 5= much
Evaluate each additional concept against the baseline, score each
attribute as: 1 = much worse than baseline concept 2 = worse than
baseline 3 = same as baseline 4 = better than baseline 5= much
better than baseline1
serv
o fo
r eac
h wh
eel
1 se
rvo
for e
ach
whee
l
2 se
rvos
, opp
osite
2 se
rvos
, opp
osite
co
rner
sco
rner
s
2 se
rvos
, Cha
in D
riven
2 se
rvos
, Cha
in D
riven
2 se
rvos
, Bel
t Driv
en2
serv
os, B
elt D
riven
2 Se
rvos
, 2 c
aste
rs2
Serv
os, 2
cas
ters
Rela
tive
Wei
ght
Rela
tive
Wei
ght
Skill to manufacture?Skill to manufacture? 3.0 3 1 1 3 6%Access to necessary tooling?Access to necessary tooling? 3.0 3 2 2 3 4%Cost of Materials?Cost of Materials? 3.0 2 2 2 3 15%Cost of Purchased Components?Cost of Purchased Components? 3.0 4 3 3 3 13%Time to assemble?Time to assemble? 3.0 4 2 2 3 9%Time to order parts?Time to order parts? 3.0 3 2 2 3 9%Time to manufacture parts?Time to manufacture parts? 3.0 2 2 2 3 11%Multiple Technologies Needed?Multiple Technologies Needed? 3.0 3 3 3 3 4%Back-up with engineering calculations?Back-up with engineering calculations? 3.0 2 1 2 3 4%Performance?Performance? 3.0 2 2 2 1 11%Ability to be used on various surfaces?Ability to be used on various surfaces? 3.0 2 3 3 1 15% Weighted ScoreWeighted Score 2.6 2.4 1.8 1.8 2.3
Normalized ScoreNormalized Score100.0
%92.5
%69.2
%70.8
%91.7
%
53
7.9 Weighted Method – FPGA
Evaluate each additional concept against the baseline, score each
attribute as: 1 = much worse than baseline concept 2 = worse than
baseline 3 = same as baseline 4 = better than baseline 5= much
better than baselineVi
rtex
4ML4
01 E
vual
Kit
Virte
x 4M
L401
Evu
al K
it
HC12
Micr
ocon
trolle
rHC
12 M
icroc
ontro
ller
Virte
x 4
ML4
02 E
vual
Kit
Virte
x 4
ML4
02 E
vual
Kit
Virte
x 4
ML4
03 E
vual
Kit
Virte
x 4
ML4
03 E
vual
Kit
6800
0 M
ircoC
ontro
ller
6800
0 M
ircoC
ontro
ller
Rela
tive
Wei
ght
Rela
tive
Wei
ght
Sufficient Student Skills?Sufficient Student Skills? 3.0 2 3 3 3 11%Processing PowerProcessing Power 3.0 2 2.5 5 2 3%Memory Memory 3.0 1 3 5 1 5%Aviable LogicAviable Logic 3.0 2 2.5 2.7 1 14%I/O PortsI/O Ports 3.0 1 3 3 1 16%Interfacing with extra memoryInterfacing with extra memory 3.0 1 3 3 1 16%Simulation of ModelsSimulation of Models 3.0 1 3 3 1 14%Cool Technology for Excitement?Cool Technology for Excitement? 3.0 1 3 4 1 3%CostCost 3.0 2 3 3 2 3%Cost of componentsCost of components 3.0 1 3 3 1 16% Weighted ScoreWeighted Score 3.0 1.3 2.9 3.1 1.3
Normalized ScoreNormalized Score100.0
%43.2
%97.3
%105.0
%42.3
%
54
7.10 Weighted Method – GPS
Evaluate each additional concept against the baseline, score each
attribute as: 1 = much worse than baseline concept 2 = worse than
baseline 3 = same as baseline 4 = better than baseline 5= much
better than baselinePM
B-24
8PM
B-24
8
PMB-
238
PMB-
238
EM-4
01EM
-401
PGM
-102
PGM
-102
Rela
tive
Wei
ght
Rela
tive
Wei
ght
Sufficient Skills?Sufficient Skills? 3.0 3 3 3 10%Sufficient Software?Sufficient Software? 3.0 3 3 3 5%Ease of UseEase of Use 3.0 2 2 2 13%Cost of Materials?Cost of Materials? 3.0 3 3 3 13%Cost of Device?Cost of Device? 3.0 3 2 2 13%SizeSize 3.0 3 2 3 13%Integrate into systemIntegrate into system 3.0 2 1 2 13%AccuracyAccuracy 3.0 3 1 1 8%Acquisition TimeAcquisition Time 3.0 3 1 2 3%Power SupplyPower Supply 3.0 3 2 3 13% Weighted ScoreWeighted Score 3.0 2.8 2.1 2.5
Normalized ScoreNormalized Score100.0
%91.7
%68.3
%81.7
%
55
7.11 Weighted Method – Servo Motors
Evaluate each additional concept against the baseline, score each
attribute as: 1 = much worse than baseline concept 2 = worse than
baseline 3 = same as baseline 4 = better than baseline 5= much
