Download Power Supply for a Remotely Operated Vehicle

Power Supply for a Remotely
Operated Vehicle
May05-12
Project Plan
Client
Stealth ISR Engineering
Scott Morgan
Faculty Advisor
Dr. Ajjarapu
Team Members
Gettler, Jonathan EE
Ong, Tai EE
White, Adam EE
Yau, Wei EE
DISCLAIMER: This document was developed as a part of the requirements of an electrical and
computer engineering course at Iowa State University, Ames, Iowa. This document does not
constitute a professional engineering design or a professional land surveying document.
Although the information is intended to be accurate, the associated students, faculty, and Iowa
State University make no claims, promises, or guarantees about the accuracy, completeness,
quality, or adequacy of the information. The user of this document shall ensure that any such
use does not violate any laws with regard to professional licensing and certification
requirements. This use includes any work resulting from this student-prepared document that is
required to be under the responsible charge of a licensed engineer or surveyor. This document
is copyrighted by the students who produced this document and the associated faculty advisors.
No part may be reproduced without the written permission of the senior design course
coordinator.
April 30, 2017
Table of Contents
List of Figures......................................................................................................... iii
List of Tables .......................................................................................................... iv
Definition of Terms ..................................................................................................v
1.0 Introductory Materials ...................................................................................1
1.1 Abstract ........................................................................................................1
1.2 Problem Statement ....................................................................................1
1.2.1 General Problem Statement ............................................................. 1
1.2.2 General Solution Approach ............................................................... 2
1.3 Operating Environment..............................................................................2
1.4 Intended User and Use..............................................................................3
1.4.1 Intended Users .................................................................................... 3
1.4.2 Intended Uses ..................................................................................... 3
1.5 Assumptions and Limitations ....................................................................3
1.5.1 Initial Assumptions.............................................................................. 3
1.5.2 Initial Limitations ................................................................................. 4
1.6 Expected End Product and Deliverables ................................................5
1.6.1 Mobile Power Supply ......................................................................... 5
1.6.2 Test Results ......................................................................................... 6
1.6.3 Manual of Operations and Specifications ....................................... 6
2.0 Proposed Approach and Statement of Work ............................................7
2.1 Proposed Approach ...................................................................................7
2.1.1 Functional Requirements .................................................................. 7
2.1.2 Constraint Considerations ................................................................. 8
2.1.3 Technology Considerations .............................................................. 9
2.1.4 Technical Approach Considerations.............................................. 10
2.1.5 Testing Requirements Considerations .......................................... 11
2.1.6 Security Considerations ................................................................... 12
2.1.7 Safety Considerations ...................................................................... 13
2.1.8 Intellectual Property Considerations .............................................. 14
2.1.9 Commercialization Considerations ................................................ 14
2.1.10 Possible Risks and Risk Management .......................................... 14
2.1.11 Project Proposed Milestones and Evaluation Criteria ................ 15
2.1.12 Project Tracking Procedures .......................................................... 16
2.2 Statement of Work....................................................................................18
Table of Contents (continued)
3.0 Estimated Resources and Schedules .....................................................22
3.1 Estimated Resource Requirements ......................................................22
3.1.1 Personnel Effort Requirements ...................................................... 22
3.1.2 Other Resource Requirements....................................................... 23
3.1.3 Financial Requirements ................................................................... 23
3.2 Schedules ..................................................................................................24
3.2.1 Project Tasks Schedule ................................................................... 24
3.2.2 Project Deliverable Schedule ......................................................... 25
4.0 Project Team Information ..........................................................................26
4.1 Client Information: ....................................................................................26
4.2 Faculty Advisor: ........................................................................................26
4.3 Student Team Members:.........................................................................26
5.0
Summary ......................................................................................................27
6.0
References ...................................................................................................28
ii
List of Figures
Figure 1: Power Supply Diagram ................................................................ 5
Figure 2: Gantt Chart of Project Tasks ...................................................... 24
Figure 3: Project Deliverable Schedule ..................................................... 25
iii
List of Tables
Table 1: Definition of Terms ........................................................................ v
Table 2: Estimated Personal Effort for Fall 2004 Semester ....................... 22
Table 3: Estimated Required Resources ................................................... 23
Table 4: Estimated Project Costs .............................................................. 23
iv
Definition of Terms
Table 1: Definition of Terms
35 g /Hz full sine wave
Measure of vibration (g=9.8m/s 2 )
CDX plywood
Standard outdoor grade plywood
C value of a battery
The amount of current that a battery
can supply per 10 hour period
DC
Direct current
MIL-STD-704C
Military standard for electromagnetic
emissions testing for government
design
MIL-STD-810
Military standard for government
design
UAV
Unmanned aerial vehicle
2
v
1.0 Introductory Materials
The following subsections describe the project problem, operating
environment, intended user, intended use, assumptions, limitations, and
deliverables.
1.1 Abstract
Stealth ISR Engineering has requested a custom designed power supply
for a remotely operated vehicle. Currently, a simple system consisting of a
generator, batteries and a load all in parallel is being utilized by the client.
This system is consistently overcharging the client’s batteries causing the
batteries to fail in a short duration of time. The client would like a design
that limits and controls the charging current absorbed by the batteries. The
load should be primarily powered by the batteries, not the generator. The
team will design a power supply that regulates the charging current into the
batteries and provides a direct connection between the load and generator
for use when the battery voltage has dropped below a given threshold. The
final power supply will be more rugged than existing systems due to longer
battery life.
1.2 Problem Statement
The problem statement outlines both the general problem and general
approach to the problem solution.
1.2.1 General Problem Statement
Currently, electrical devices in remotely operated vehicles used by the
client are powered by a combination of a battery and a DC generator
connected in parallel. An engine turns the generator that charges the
battery. The load is directly connected to the battery, which is in turn
directly connected to the generator. The client has been having problems
with batteries being overcharged. The client would like a new system
designed that increases battery life by reducing overcharging and
overheating. The generator will only supply power to the load when battery
1
power is insufficient. At all other times, the generator should be solely
supplying power to the batteries for charging.
1.2.2 General Solution Approach
The client is going to be sending a gasoline engine and generator
combination to Ames. The design team will be responsible for taking the
output from that generator and supplying DC power at 12V, 5V and 3.3V.
Voltage from the generator will first be regulated to a constant voltage to be
determined. Direct voltage from the generator will vary significantly
depending upon the rotational speed of the engine, which will also vary
significantly during operation. Next, the current from the voltage regulator
to the batteries will be regulated to charge the batteries at the proper
current. Appropriate batteries will be chosen to supply necessary power to
the client’s load. A multiple voltage output unit will be connected to the
battery bank in order to supply the voltages specified by the client. The
output unit will consist of several DC to DC converters that will provide
different source voltages required by the client. Battery voltage will be
monitored during operation. If battery voltage falls below a set minimum,
then the regulated voltage from the generator will be used to replace the
power supplied by the batteries to the multiple voltage output unit. A switch
will open to prevent current from flowing through the output unit back to the
batteries.
1.3 Operating Environment
The power supply will be onboard a remotely operated vehicle subject to
varying temperature and extreme vibration. The client has specified that
the power supply shall be able to withstand temperatures from 125° to –37°
Fahrenheit. The power supply will be tested to withstand vibration on a 35
g 2 /Hz full sine wave for 1 hour by the client. The power supply should also
be rugged enough to withstand a 5 foot drop from a table onto a ¾” thick
sheet of CDX plywood.
2
1.4 Intended User and Use
Stealth ISR Engineering will use the power supply for the purpose of
providing power at 12V, 5V and 3.3V to electronics onboard a remotely
operated vehicle. The following information describes the intended user
and the intended uses.
1.4.1 Intended Users
Citing security concerns, Stealth ISR Engineering has decided to withhold
specific information regarding the final use and users of the power supply.
It seems reasonable to assume that users of this product will be properly
trained to handle such equipment.
1.4.2 Intended Uses
The power supply will be used by the client on an unspecified unmanned
aerial vehicle. The power supply will have to operate unspecified
electronics onboard the aircraft. The design team will develop a rugged
power supply in the event that the power supply will have to operate
mission critical systems.
1.5 Assumptions and Limitations
The assumptions and limitations outlined herein will be used in designing
the desired end product for the client.
1.5.1 Initial Assumptions
The following assumptions have been made regarding the power supply
design.
 The generator output voltage can be regulated while the generator is
operating between 2,500 and 13,000 rpm.
 Current flowing into the batteries can be regulated.
 Only one voltage will be used at a time from the power supply.
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 If the designed system will operate within specifications on the
surrogate engine and generator assembly being sent to the design
team by the client, the power supply will also operate within
specifications on the engine and generator that the client will actually
be using on the remotely operated vehicle.
 End users will have the proper training to maintain and install the end
product.
1.5.2 Initial Limitations
The following limitations will be part of the power supply design.
 The generator will be a brushless motor driven directly (1:1 gearing)
by a 4-cycle gasoline engine.
 The power supply will output the following voltages:
o DC 12 V +.4/-.2 V
o DC 5 V +.2/-.1 V
o DC 3.3 V +.1/-.05 V
 The power supply must be capable of supplying 150 watts continuous
power at DC 12 V.
 There shall be less than .05 Vrms noise in the output voltage.
 The power supply will have overvoltage and undervoltage protection
for voltages outside the acceptable range for more than 1 ms.
 The batteries must be capable of supplying the rated power for 15
minutes without being charged simultaneously by the generator.
 Emissions shall conform to MIL-STD-704C.
 The power supply shall conform to size and weight requirements to
be specified by the client as soon as possible.
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1.6 Expected End Product and Deliverables
The expected end product will be a prototype mobile power supply for use
in a UAV. Test results and a manual of operations and specifications will
also be delivered to the client. The mobile power supply will consist of all
electronics used from the generator output to the specified output voltages.
1.6.1 Mobile Power Supply
At this time, the design team expects the deliverable electronics to include
but not be limited to:
 A voltage regulator to regulate generator output.
 A current regulator to limit charging current to the batteries.
 A bank of batteries.
 Electronics to facilitate switching of load between the batteries and
generator directly.
 Overvoltage and undervoltage protection devices.
 DC to DC voltage converters to provide the specified output
voltages.
DC
Generator
Variable
Voltage
Voltage
Regulator
Fixed
Voltage
Current
Regulator
Fixed
Charging
Current
Batteries
Standard
Power
Source
Auxiliary
Power
Source
Switching
Logic
Buck DC
Converter
12
Vdc
Figure 1
Figure 1: Power Supply Diagram
5
5 Vdc
3.3
Vdc
1.6.2 Test Results
The deliverable test results will include all specifications of the performed
test and the results. The data presented in this document will clearly
display the success or failure of the project under the given tests. These
materials will be provided to the client as a bound document when the end
product is released.
1.6.3 Manual of Operations and Specifications
A manual of operations and specifications will also be delivered to the
client. Material in this document will consist of the hazards and warnings
associated with the power supply, as well as technical documents on the
components included in the design. This material may be presented as a
bound document for the client or may be a folder consisting of data sheets.
Any hazards or warnings associated with the power supply will be clearly
defined in the manual of operations.
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2.0 Proposed Approach and Statement of Work
The proposed approach and statement of work provide the team with a
plan of action for the remainder of the design period.
2.1 Proposed Approach
The following subsections will list, in detail where appropriate, the
requirements and considerations incorporated into the project. This section
will specify what the project is intended to do, as well as what the project is
not intended to do.
2.1.1 Functional Requirements
Functional requirements are intended to clearly define what the project
should and should not do.
 The power supply should output three nearly constant voltages.
o 3.3 Vdc with voltage variation within +.1/-.5V
o 5 Vdc with voltage variation within +.2/-.1V
o 12 Vdc with voltage variation within +.4/-.2V
 Each output voltage should have a voltage ripple of less than .05
Vrms. For the application of this power supply in a UAV, fluctuations
in voltage must be strictly maintained to assure no equipment
damage or power failures occur.
 The power supply should output 150 watts continuous power at 12
volts. The client has indicated that 150 watts may be unachievable at
the lower voltage levels, in particular the 3.3 volt and 5 volt levels,
due to the accompanying high currents. At these voltages the client
would like the team to “push the envelope,” allowing the supply to
produce as close to 150 watts continuous power as is reasonable.
 The circuitry of the project should contain circuit protection amenities.
For any unacceptable voltage the power supply is subject to for a
duration of more than 1ms, the circuit must have a protection system
incorporated to defend the system.
 The power supply should comply with the MIL-STD-704C. The power
supply must not cause interfere with other components on the UAV.
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 The design of the power supply should incorporate the use of
batteries that will supply the system rated current for a duration of 15
minutes. The application of the power supply will be used in an
environment where the generator may not be active, resulting in all
power requirements be supplied by the battery for a period of time.
2.1.2 Constraint Considerations
Constraint considerations are items that limit physical tolerances,
economical tolerances, or any other tolerance that affects the final form of
the end product.
2.1.2.1 Physical Strength
 The power supply will be incident to harsh environmental
conditions and must be able to operate under the following
conditions:
o Temperature range of 125° Fahrenheit to -37° Fahrenheit
o 5 temperature cycles of 1° every 5 minutes, as specified in the
MIL-STD-810
o Saturation in each extremis temperature for 15 minutes
 The power supply shall be designed to withstand vibrations of 35
G squared Hz full since wave for 1 hour. This vibration constraint
should comply with MIL-STD-810.
 The power supply shall withstand a 5 foot drop onto ¾” CDX
plywood, as specified by the client.
2.1.2.2 Weight and Dimensions
The designated area in the UAV will need to be shared between the
gasoline motor, generator, batteries, and power supply. These four
major components need to be designed with considerations of one
another to ensure maximum utilization of the available space.
Stringent weight constraints will also be applied to this project, as with
any aviation related project. These size and weight constraints are
currently unknown, although the client has indicated that specification
of these constraints will become available on or before September 24.
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2.1.2.3 Cost
The revenue for the project is $500. Consultation with the client may
result in more project revenue, as discussed in previous team-client
communications.
2.1.3 Technology Considerations
Several technologies will be used in the development of the power supply.
Technology considerations include available products that will save time
and money in the completion of the power supply as well as indicate areas
that should be researched before a selection can be made.
 Several semiconductor technologies are available for selection
research. Thyristors, transistors, and diodes are some of the
available products that may be selected. The high current capability
of the power supply indicates that MOSFET type devices may be a
good choice.
 The power supply will need to convert DC power to several different
voltages. Depending on the output voltage from the generator, there
are several types of converters to choose from. Research will need
to be completed on the following technologies:
o Buck Chopper
o Boost Chopper
o Buck/Boost Chopper
 The generator that will provide the link from mechanical power to
electrical power should also be researched. The client has specified
a brushless DC generator, although research on the excitation
voltage and operating RPM should be completed.
 Batteries for the back up capability of the power supply must also be
researched. Preliminary data from the client indicates dry cell
technology or gel cell technology are the two preferred products.
 Modeling of the generator or the choppers may require the use of
software such as Dymola or Spice. These software programs will aid
the necessary calculations and allow the team to more quickly and
efficiently solve the problem.
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2.1.4 Technical Approach Considerations
The technical approach considerations will allow the team to define the
methodologies that will be used in the completion of the power supply.
This section will display the approaches considered in the design process.
The design of the power supply should be divided into the following four
categories.
2.1.4.1 Generator Research and Analysis
The client will supply the team with a brushless DC generator and a 4cycle gasoline motor.
Research should be completed on the
horsepower characteristics of the motor corresponding to the RPM
necessary for the electrical requirements of the system. An excitation
voltage must be chosen to supply the proper electrical characteristics
while the RPM fluctuates from 2,500 to 13,000 RPM. Voltage
regulation from the output of the generator should also be researched
in this process. This approach will allow the team to build a firm
foundation of electrical supply from a mechanical process.
2.1.4.2 Battery Research and Selection
The capability of the power supply relies on the battery. The client has
specified existing problems with power supplies similar to the one the
team will be designing. Research will need to be completed on “c”
values of batteries as well as the other constraints listed in section
2.1.2. The team will complete battery selection after proper research is
completed and all criteria have been meet. Solving all battery issues is
a vital step in solving problems with existing designs used by the client.
Consequently, the batteries will be chosen before the remainder of the
power supply is designed.
2.1.4.3 Power Converter Design
The power converter design process can begin after proper research
has been completed on the above two topics. This step will allow the
team to analyze the proper type of converter to use.
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2.1.4.4 Protection and Reliability Circuitry
Designing protection and reliability circuitry will be the last design
steps. This approach will allow the team to collaborate the individual
pieces from above to form a finished product. Criteria specified by the
client, such as the overvoltage/undervoltage protection, will be
incorporated into this design. The reliability concerns included in this
circuitry will assure that all performance criteria have been met.
2.1.5 Testing Requirements Considerations
Testing considerations are a significant part of the power supply
design. It is important that the team test each component that is built
to assure the client that the power supply meets the given constraints.
Existing power supplies are an option for the client to purchase,
although they do not accommodate the features requested. Therefore,
the team’s end product should accommodate all the requested
features as well as perform equal to or better than existing power
supplies.
To effectively test the operation of the power supply, each component
will be built and tested individually. Afterwards, the completed system
will be tested as a whole.
The following items describe the
components to be tested and the tests that will be applied:
 The generator and voltage regulator should be tested under the
operating RPM range to assure that a proper voltage is achieved.
This will be accomplished by mounting the generator to the
motor. The voltage regulator will be connected to the generator
outputs. The RPM of the engine will then be varied while a digital
multimeter is used to record voltage output of the regulator.
 The batteries will be tested when fully charged. The batteries will
be the sole source of power to the power converter during the
test. A 150 watt continuous power load will then be connected to
the power converter at 12V DC. Voltages will be recorded every
3 minutes in order to verify that the batteries alone will supply
150 watts continuous power for at least 15 minutes.
 The power converters will be tested using a digital multimeter
and an oscilloscope to measure and record the voltage outputs
and the voltage ripple.
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 The protection and reliability circuitry will be tested by following
the operation procedure on the equipment while recording data
to compare with the individual specifications. This test cannot be
fully completed until a prototype has been constructed.
 The temperature, vibration, and radiated emissions will need to
be completed at Stealth ISR Engineering in Eagan, Minnesota.
Consultation with the client has indicated that any test that
cannot be completed at ISU can be completed at the client’s
laboratory. Results of these tests must comply with the MILSTD-810 and MIL-STD-704C.
All equipment tests must satisfy the specifications indicated by the
client, otherwise the test will be considered a failure.
2.1.6 Security Considerations
Security considerations for the power supply design will be considered in
two phases.
The first phase, or scope, of security is during the
development of the power supply. The second phase of security to be
considered is end product security.
There are several unknown security issues associated with the application
of the power supply. Stealth ISR Engineering has chosen to not share
confidential information with the design team and has indicated through
telephone conversations that confidential information will not be released
unless absolutely necessary for the project design. Assuming that the
client continues to withhold confidential information, the security
considerations of the project for the team are minimized.
Security considerations associated with the actual end product may include
issues related to patents. It is possible that the innovative design of the
power supply may lead to a patent. It will be important to not publicly
reveal, in detail, the design of the power supply components.
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2.1.7 Safety Considerations
Safety concerns will be a reoccurring theme throughout the design process
of this project. Safety considerations are most important in the use and
maintenance of the end product. Manufacturing and disposal safety
concerns are minimal. There are several different scopes throughout the
project. The scopes have been subcategorized on the following page.
2.1.7.1 Unmanned Aerial Vehicle Scope
Stealth ISR Engineering is liable for the safety of the operation of the
finished UAV. Several mechanical safety issues must be considered
from their industrial standpoint, as well as electrical safety issues. The
team will keep in mind the application of the power supply and will
incorporate circuitry into the design that will allow the power supply to
fail to a safe configuration. The client expects safety issues to be
clearly indicated to assure that a failure in the power supply will not
result in an unsafe condition for the aircraft or people operating the
vehicle.
2.1.7.2 Power Supply Scope
The team will need to design the power supply to be within acceptable
standards in terms of current ratings and radiated emissions. The
project will be capable of supplying large amounts of current and all
team members and faculty working on the project must use safe
practices around the power supply.
2.1.7.3 Initial Testing Scope
The team will be responsible for the initial testing of the power supply
in the ISU labs. It is important that the first users of the project are
aware of the safety concerns with the project (meaning that the initial
users must understand the operation of the system). The power
supply will provide large currents that will cause significant damage to
humans or surrounding equipment. Extreme caution should be used
when performing maintenance or trouble shooting any of the circuitry.
2.1.7.4 End User Scope
It is assumed that proper training will be issued to those that will
operate the UAV, as well as mechanics or technicians who will install
or maintain the power supply. Considerations incorporated into the
design of the power supply are as follows:
13
 Clear concise labeling of outlets and or switches will help users
of the end product become familiar with the functionality of the
project.
 Hazard indicators and warnings should be applied where
appropriate on the project indicating areas where extra safety
should be taken to avoid injury.
2.1.8 Intellectual Property Considerations
The senior design team will be investing many hours of personal effort into
this project. The team feels that it is important that they be properly
recognized for their efforts. Accordingly, the team will be careful regarding
what documents and ideas are made public, particularly on the design
team’s web page.
2.1.9 Commercialization Considerations
Commercialization considerations should be developed for the project.
Although the project is being designed for a specific application, the power
supply will have the ability to be a “stand alone” component used for other
applications. Proper documentation should be compiled for evidence of
individual thought that may be applied to the design of the power supply.
Patents are a possible outcome for the project, considering the wide
application that the power supply could apply towards.
2.1.10 Possible Risks and Risk Management
The design process of the power supply has several associated risks. The
team members need to accurately and honestly document all work
completed. All team members realize that there is a possibility that
someone will leave the project (internships, family issues, death, etc.).
The team’s strategy for managing risk is to properly document the work
completed so that new members may be added to the project and will have
the ability to begin work where previous members ended. The team will
also keep electronic documents of all materials including hard copies of
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documents. The project leader as well as the communication coordinator
will back up electronic materials.
2.1.11 Project Proposed Milestones and Evaluation Criteria
The project team has selected eight measurable milestones, listed below,
for use in evaluating this project. Each milestone is accompanied by a
weighted percentage which corresponds to component importance.
2.1.11.1 Measurable Milestones
 Problem Definition (18%)
o Problem Definition is the process of getting a clear picture of
what existing system the team is going to be given by the
client (input), and knowing what the client wants to be the
output of the final system to be once the designed hardware is
added to the existing system.
 Research (16%)
o Research is the process of getting the required background
knowledge to be able to make wise decisions when deciding
how to design the needed hardware for the client. Research
will be necessary in order to evaluate the use of potential
technologies.
 Technology Selection (18%)
o Technology selection is choosing the best possible technology
to give the client the power supply specified while staying
within the project budget.
 End-Product Design (18%)
o End-product design is comprised of the written specifications
and decisions on what hardware components will be used in
the end-product, and how those hardware components will be
assembled into a power supply for the client.
 Prototype Implementation (10%)
o Prototype implementation is the stage in which all parts have
been assembled into a working, testable product.
 End-Product Testing (10%)
o End-product testing is the process of taking the assembled
prototype and testing to see if it meets the client’s
requirements.
15
 End-Product Demonstration (10%)
o End-product demonstration is taking the final product,
including changes in the prototype made after testing, and
showing the client and faculty the product’s effectiveness.
2.1.11.2 Evaluation Criteria
After the completion of every milestone, the team will evaluate that
milestone. Each milestone will be rated on one of the following
categories:
o Expectations exceeded
120%
o Expectations met
100%
o Expectations almost met
70%
o Expectations not met
40%
o Milestone not reached
0%
The project as a whole will be evaluated by multiplying the weight of
each milestone by its evaluation percentage. The resulting number
multiplied by 100 will be the evaluation percentage for the whole
project. This percentage will be interpreted using the same scale used
for individual milestones above. Considering the magnitude of the
project, seventy percent will be considered a passing score.
2.1.12
Project Tracking Procedures
It is essential that the project team be able to track project success as well
as maintain the projected work schedule. The primary tracking procedure
that the team will use will be to frequently remove ourselves from the
details of the project and evaluate the completion of the end product. The
team will strive to meet project requirements, keep the project on schedule
and keep the project within budget.
2.1.12.1 Project Requirements Tracking Procedures
Project requirements will be tracked by intermittently evaluating current
tasks to ensure that they benefit the end project. A clear project
definition will help the team meet all requirements of the project.
2.1.12.2 Schedule Tracking Procedures
A main focus of the team is to keep on schedule. The use of a Gantt
chart will allow the team to assign a flexible schedule of events to the
16
subtasks that must be completed. It is important that realistic data and
concerns are incorporated into the schedule. The following is a list of
concerns that should be evaluated when making the schedule.
 Time required to order parts.
 Time required to replace or fix parts or circuits.
 Extra time required by underestimating the difficulty of a task.
 Extra time required in the event of team member illnesses.
2.1.12.3 Budget Tracking Procedures
The team has a five hundred dollar budget for the purchase of parts
and material. It is important that the project does not exceed this
amount, although in telephone conversations the client has indicated
that more money may be available. All purchases will be accurately
documented and a project balance will be logged throughout the
project. There are several factors that will allow the team to stay within
the provided budget. They are listed below.
 Minimize the shipping on parts orders by ordering multiple parts
in unison.
 Reuse any parts that are available within the department or from
previous projects.
 Handle all parts carefully, making sure no items are damaged.
 Use care when testing any circuitry so that additional parts and
time will not be required to fix testing errors (especially true when
the team will begin environmental testing and pushing the limits
of the components).
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2.2 Statement of Work
The statement of work section lists all tasks that the team needs to
complete during first and second semesters from September 2004 through
May 2005.
Task 1- Problem Definition
Task Objective: The goal for this project is to develop a power supply for a
small mobile mission system.
Task Approach: The team will research the problem in depth and
communicate with advisor as well as the client in order to thoroughly
understand how to avoid the existing problems with available power
supplies. Research resources will include but not be limited to, the internet,
textbooks, professors and other technical professionals in the field.
Task Expected Result: All the team members will fully understand the
project and be able to methodically solve design issues.
Task 2-Technology and Implementation Considerations and Selection
Task Objective: Use available technologies to design a cost effective
power supply for the client.
Task Approach: Team members will research through the internet and
catalogs, the available technology for system components.
Task Expected Result: A rugged and cost effective power supply design
for the client.
Subtask 2a- Power Output
Subtask Objective: Meet client’s design specifications for power
delivery.
Subtask Approach:
Use basic power equations to calculate
necessary currents at desired voltage levels, after determining the
horsepower abilities of the gasoline engine.
Subtask Expected Result: 150W continuous power output at 12Vdc
when the generator is being driven from 2,500 RPM to 13,000 RPM.
Subtask 2b-Generator Voltage Regulation
Subtask Objective: Use voltage regulation to control generator output
voltage.
Subtask Approach: Purchase or build a quality regulator.
Subtask Expected Result: Appropriate voltage for the batteries or DC
to DC power converters to use.
18
Subtask 2c-Battery Selection
Subtask Objective: Select batteries that meet the client’s size, weight,
and capacity requirements.
Subtask Approach: Choose the most cost effective batteries that
meet the above requirements and can be quickly charged.
Subtask Expected Result: The batteries will be able to supply full
rated load for 15 minutes without being simultaneously charged.
Subtask 2d- Battery Charging Current Limiter
Subtask
Objective:
Protect
batteries
from
being
overcharged/overheated.
Subtask Approach: The team will design or purchase components to
control the current entering the batteries.
Subtask Expected Result: The batteries will not overcharge or
overheat.
Subtask 2e- DC to DC Power Converter
Subtask Objective: Convert the generator and battery voltage level to
specified output voltages.
Subtask Approach: The team will be use Dymola software to create
DC to DC converters that meet the requirements.
Subtask Expected Result:
Output voltages within the client’s
specifications.
Subtask 2f- Overvoltage/Undervoltage Protection
Subtask Objective: Protect loads connected to the power supply from
overvoltage and undervoltage conditions.
Subtask Approach: Select technology that will protect and correct the
circuit if an overvoltage or undervoltage condition exists.
Subtask Expected Result: Circuit will automatically protect and
correct itself if voltage ratings are violated for more than 1 ms.
Subtask 2g- Switching Circuit
Subtask Objective: Create a switching circuit to apply generation
directly to load if the voltage in battery is low.
Subtask Approach: The team will research automatic switching
technologies, and choose the technology that best fits the given
situation.
19
Subtask Expected Result: The switching circuit will able to switch to
the generator if the battery voltage is below a specified threshold.
Subtask 2h- Noise Suppression
Subtask Objective: Determine if additional components are needed
to meet noise suppression requirements.
Subtask Approach: Use material from EE303, EE452, and various
Signals and Systems courses to evaluate circuit noise.
Subtask Expected Result: Total noise less than .05Vrms.
Subtask 2i- Temperature
Subtask Objective: Ensure that the system can withstand the client’s
specified temperature range.
Subtask Approach: The prototype will be sent to the client’s lab for
temperature testing. This test will be entirely completed by the client.
Subtask Expected Result: Circuitry will withstand conditions from
125° to –37° Fahrenheit and 5 temperature cycles of 1° every five
minutes.
Subtask 2j- Vibration
Subtask Objective: Ensure that the prototype can withstand vibration
specified by the client.
Subtask Approach: The prototype will be sent to the client’s lab for
temperature testing. This test will be entirely completed by the client.
Subtask Expected Result: The prototype will withstand a 35 g 2 /Hz full
sine wave for 1 hour during testing.
Task 3- End product Design
Task Objective: Use Dymola software to simulate and design the end
product.
Task Approach: Team will use techniques from EE 452 (Electrical
Machines and Power Electronic Drives) lab to complete the schematic.
Task Expected Result: Design that is ready for prototype implementation.
Task 4 – End product Prototype Implementation
Task Objective: Construct a product prototype.
Task Approach: Using parts that meet design constraints, construct a
prototype power supply.
Task Expected Result: A working prototype that can be tested.
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Task 5- End product Testing
Task Objective: Verify that the prototype will meet required specifications.
Task Approach: Use laboratory equipment to test the prototype for all
specifications. Testing will require the use of oscilloscopes, multimeters,
and an RPM gauge.
Task Expected Result: Rugged power supply that meets the client’s
needs.
Task 6 – End product Documentation
Task Objective: The team will compose a document for the end-user. This
will include; product information, part numbers, troubleshooting
suggestions, and maintenance schedules for the product.
Task Approach: The team will use the information acquired during the
design process to write the end-user manual.
Task Expected Result: The manual and specification document will be
given to the client with the prototype.
Task 7 – End product Demonstration
Task Objective: The team will plan a demonstration to present to the
faculty advisor and client in EE 491.
Task Approach: Schedule and prepare a product demonstration.
Task Expected Result: The demonstration should verify that the completed
prototype meets both client and class requirements.
Task 8- Project – Reporting
Task Objective: The designers will clearly report project status throughout
the duration of the project to the client, advisor and instructors.
Task Approach: The team will keep the client, advisor and instructors
informed by sending regular emails as outlined in the class notes. A report
will be developed when the project is completed.
Task Expected Result: All activities will be clearly documented throughout
the project duration. If necessary, anyone new to the project will be able to
be brought up to date by reviewing reporting done by the team throughout
the project.
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3.0 Estimated Resources and Schedules
When developing the power supply several factors need to be considered.
Resources, cost estimates and task schedules have to be planned in order
to use time and money efficiently. The following are the estimated
resources and schedules for the design team working on a Power Supply
for a Remotely-Operated Vehicle.
3.1 Estimated Resource Requirements
The following sections will cover the expected personal effort of each team
member, other resources requirements and financial requirements for the
project.
3.1.1 Personnel Effort Requirements
An estimate of the anticipated personal effort of each member of the team
is shown in Table 2. Our team will work mainly on tasks one, two and three
during the first semester. All other tasks will be completed during the
second semester. The team will be designing and testing a prototype.
Table 2: Estimated Personal Effort for Fall and Spring semesters
Team
Task Task Task Task Task Task Task Task
Total
Member
1
2
3
4
5
6
7
8
Gettler,
23
52
53
30
19
25
31
23
256
Jonathan
Ong, Tai 18
53
57
30
19
25
36
18
256
White,
25
50
53
30
19
25
29
25
256
Adam
Yau,
22
53
53
30
19
25
32
22
256
Wei
Total
88
208
216
120
22
76
100
128
88
1024
3.1.2 Other Resource Requirements
An estimated financial budget of materials to be purchased during the work
period in order to complete the project is shown in Table 3.
Table 3: Estimated Required Resources
Team
Other
Items
Cost
Hours
Hours
Parts and
Materials
a. Project Poster
15
0
$50.00
b. Project Parts
10
0
$500.00
Total
25
$550.00
3.1.3 Financial Requirements
This section covers the total financial resources required to conduct the
project for the entire year. Table 4 displays all costs anticipated for the first
half of the project, including include parts, materials and labor.
Item
Table 4: Estimated Project Costs
Without Labor
With Labor
Parts and Materials:
Project Poster
Project Parts
Subtotal
Labor ($10.30 per
hour):
Gettler, Jonathan
Ong, Tai
White, Adam
Yau, Wei
Subtotal
Totals
$50.00
$500.00
$550.00
$50.00
$500.00
$550.00
$0
$0
$0
$0
$0
$2636.80
$2636.80
$2636.80
$2636.80
$10547.20
$550.00
$10547.20
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3.2 Schedules
The key to a successful project is meeting deadlines. The team has
developed the following projected schedules for the completion of tasks
and subtasks through May 2005.
3.2.1 Project Tasks Schedule
The project will span the length of two semesters. The project schedule
begins in September and will end in early May. The chart on the following
page depicts the projected tasks and subtasks to be completed versus the
proposed project calendar.
Figure 2: Gantt Chart of Project Tasks
24
3.2.2 Project Deliverable Schedule
Figure 3 displays the team’s project deliverable schedule. This schedule
will cover the entire project (two semesters) and will help the team realize
when deadlines are approaching.
Figure 3: Project Deliverable Schedule
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4.0 Project Team Information
The project team is composed of four senior Electrical Engineering
students. The project sponsor is Scott Morgan of Stealth ISR Engineering.
With the guidance of the faculty advisor the team should be able to
successfully complete the Power Supply of a Remotely Operated Vehicle
on schedule. The following sections contain the contact information for all
directly involved persons.
4.1
Client Information:
Stealth ISR Engineering
Scott Morgan
215 Prescott St.
St. Paul, MN 55107
Phone: 651-210-6620 / 651-456-2304
Email: [email protected]
4.2
Faculty Advisor:
Dr. Venkataramana Ajjarapu
1122 Coover Hall
Ames, IA 50011-3060
Phone: 515-294-7687
Fax: 515-294-4263
Email: [email protected]
4.3
Student Team Members:
Jonathan Gettler
1407 Georgia Ave. #2
Ames, IA 50014
Phone: 515-460-2686
Email: [email protected]
Tai Ong
3507 Lincoln Way #21
Ames, IA 50014
Phone: 563-650-9073
Email: [email protected]
Adam White
112 S Hyland #4
Ames, IA 50014
Phone: 563-357-3542
Email: [email protected]
Wei Yau
4400 Westbrook Dr. #21
Ames, IA 50014
Phone: 515-451-9325
Email: [email protected]
26
5.0 Summary
Currently, the client supplies power to electrical devices in remotely
operated vehicles with a combination of a battery and a DC generator
connected in parallel, much like the system in an automobile. The load is
directly connected to the battery, which is in turn directly connected to the
generator. However, the client has been experiencing problems with
batteries being overcharged in this configuration. The senior design team
will develop a new system for the client to eliminate the overcharging
problem.
This project plan will serve as an outline of the activities to be performed by
the design team in the next eight months. Project tasks clearly define what
actions the design team must take to successfully complete the project.
The project schedule in the Gantt chart coordinates when the design team
must complete these project tasks. Using the preceding plan, the design
team is confident that the product delivered to the client in May will be a
complete success.
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6.0 References
1. Hart, Daniel W. Introduction to Power Electronics. New Jersey:
Prentice Hall, Inc. 1997
2. Hobbico Inc. “Surpass Series” Hobbico Inc. 1997-2004. 9/9/04.
<http://www.osengines.com/engines/surpass.html>
3. [email protected]. “B40 Series Motors” Hacker Brushless
Motors. 9/9/2004.
<http://www.hackerbrushless.com/motors_b40.shtml>
4. Karadsheh, Fares, et. al. “Multiple-Output, Variable-Output DC Power
Supply (Phase 2) May04-08” Iowa State University. 4/20/2004.
9/02/2004. <http://seniord.ee.iastate.edu/may0408/>
5. [email protected]. “Sullivan Products” Sullivan
Products. 2004. 9/08/2004. <http://www.sullivanproducts.com>
28