Requirements Flow Down - University of Colorado … · Web viewA full-wave bridge rectifier is preferred, as it will is more efficient than a half-wave rectifier. The rectifier is

Colorado Space Grant Consortium

GATEWAY TO SPACE FALL 2010

DESIGN DOCUMENT

Lightning Rod

Written by: Christopher Bennett, Matthew Dickinson, Jesse Ellison, Matthew Holmes,

Trevor Luke, Sushia Rahimizadeh, Alex Shelanski

October 5th, 2010Revision A/B

Revision Log

Revision Description DateA/B Conceptual and Preliminary Design Review 10/5/10

Table of Contents

1.0 Mission Overview……………………………………………………………………….........42.0 Requirements Flow Down………………………………………………………………........53.0 Design…………………………………………………………………………………….......64.0 Management………………………………………………………………………................125.0 Budget……………………………………………………………………………………….146.0 Test Plan and Results………………………………………………………………………..147.0 Expected Results…………………………………………………………………………….15

Gateway to Space ASEN 2500 Fall 2010

1.0 Mission Overview

1.1 Statement The mission of Team Lightning Rod is to send Zeus, a cubic balloon satellite built from foam core and equipped with two electromagnetic generators, to an altitude of thirty kilometers and harness the vibrational and rotational energy experienced during its ascent and descent. A microcontroller will measure the amount of energy the electromagnetic generators produce. By analyzing the data collected, team Lightning Rod will determine if future spacecraft will be able to utilize energy generated by vibrational and rotational motion as additional alternative energy sources.

1.2 Goal and Background

The goal of this mission is to determine if vibrational and rotational energy can be harnessed as supplemental energy sources for future spacecraft. If this mission is successful, future spacecraft will be able to utilize these additional sources of energy, thereby providing their projects with increased security and protection from complications due to power failure. One of the most common reasons for spacecraft failure is power loss. Most satellites rely on stored battery power and solar energy to power their systems. Batteries are not ideal because they do not last infinitely and can only be recharged when solar panels receive direct sunlight. Solar panels limit the spacecraft because they must be large enough to provide energy. Thus, solar panels add a heavy weight restriction to the spacecraft. Also, solar panels are fragile and break easily when the satellite encounters debris or atmospheric turbulence. Solar panels are particularly vulnerable when the rectangular body of the solar panel extends out from the satellite and is narrowly attached to the structure. Because satellites are limited in their ability to power systems, energy supply is the satellites most important system. If power fails, all other systems fail. Thus, additional sources of power are greatly needed. The energy harnessed from vibrations and rotations is not expected to be enough to fully power all satellite systems. Nonetheless, it would prolong the life of a satellite and prevent mission failure.

The idea of generating power from vibrations was researched by students at the University of Southampton in England. The students developed a micro scale vibrational generator that was capable of powering wireless sensors. Although the design was only experimented on an air compressor, they stated in a journal that was submitted to the Journal of Micromechanics and Microengineering that they believe similar and suitable vibrations could be found in airplanes as well. In a book called Energy Harvesting Technologies by Shashank Priya and D. J. Inman, it was also discussed that there is an observed increase in power generation as generators increase in size. Considering that the generator developed by team Lighting Rod will be subjected to an environment comparable to airplanes and that its design is larger than the design developed at the University of Southampton, and thus more efficient, team Lightning Rod anticipates that the vibrational generator they develop will produce more power.

By testing two generators that harvest the energy from rotational and vibrational motion, team Lightning Rod will analyze the efficiency of the designs and determine if either design could be used to generate energy for future spacecraft. Research can be found on similar instruments that

Team Lightning Rod Page 4 of 16 October 4th, 2010

priceja, 10/08/10,

Great, it’s clear and concise

priceja, 10/08/10,

If you’re claiming that your system is better, it would be good to have some sort of ratio. It would be interesting to compute the energy you can capture and compare it to some solar panel data vs weight for both systems

priceja, 10/08/10,

Do you have a reference for this?

priceja, 10/08/10,

I’m glad you have background in here showing that you have done research and aren’t just choosing designs out of thin air


were developed for the purpose of non-aerospace applications, which will serve as the basis for the initial developments for the rotational generator. Students at the Imperial College in London also developed an energy harvester for powering wireless sensors using the rotations of the harvester's environment to create a dynamic magnetic field. As they stated in a paper titled Wireless Sensor Node Using a Rotational Energy Harvester with Adaptive Power Conversion, they sought a compliment to vibrational energy harvesting technology in order to maximize the potential of a given mechanical system's ability to gather energy. Their design consists of a mass atop a rotational disk that is offset from the center. Team Lightning Rod chose to arrange their magnets uniformly on the outer edges of the disc for the purpose of maintaining higher rotational speeds.

2.0 Requirements Flow Down

The requirements flow down is designed to portray how the requirements relate to the objectives and the goal. The goal is derived from the mission statement. Then, the level 0 requirements are the mission objectives. The mission objectives are derived exactly from the goal and mission requirements presented by Space Grant. Finally, each objective has several requirements underneath it that explain how it will accomplish the objective. The requirements are considered level 1 requirements on the flow chart. In the chart, the name of the objective or requirement is in the left column, the middle column has the specific objective or requirement, and the far right column shows where that specific goal or requirement is referenced.

The goal of team Lightning Rod is to send a balloon satellite equipped with two electromagnetic generators to an altitude of thirty kilometers to determine if the kinetic energy from vibrational and rotational motion can be harnessed as supplemental energy source for future spacecraft.

Objective Mission Objectives Level 0 ReferenceO1 Fly a satellite to 30 km Goal (G)O2 Keep the internal temperature of the satellite above -10 degrees Celsius Goal (G)O3 Keep the overall weight of the satellite below 850 g Goal (G)O4 Fly a Cannon Camera and the HOBO datalogger on the satellite Goal (G)O5 Capture and store vibrational energy using the vibrating electromagnetic generator Goal (G)O6 Capture and store rotational energy using the rotating electromagnetic generator Goal (G)O7 Compare the results of the rotational generator and the vibrational generator to see

which one is most effectiveGoal (G)

Requirements Objective 1 Requirements Level 1 ReferenceO1.R1 Satellite Zeus will be attached to a helium weather balloon that will carry it up to

30 km.O1

O1.R2 Satellite Zeus will be attached to the balloon on a piece of rope that will run directly through the center of the satellite.

O1

O1.R3 Satellite Zeus will be kept stable on the rope by using washers and clips. O1

Requirements Objective 2 Requirements Level 1 ReferenceO2.R1 Satellite Zeus will be kept above -10 degrees by using an electric heater that will

be created by Team Lightning Rod and will be powered using 9V batteries.O2

O2.R2 Satellite Zeus will have ½ inch foam insulation to keep the Satellite above -10 degrees Celsius

O2

O2.R3 Satellite Zeus will also have no holes to contain the heat in the satellite. O2


Chris Koehler, 10/11/10,

Excellent.

priceja, 10/08/10,

Good format, easy to read, but make sure that your requirements say “shall” instead of “will”


Requirements Objective 3 Requirements Level 1 ReferenceO3.R1 Satellite Zeus will be less than 850 grams by keeping a very meticulous budget

that keeps track of the weight of every piece of equipment that will be on the satellite.

O3

Requirements Objective 4 Requirements Level 1 ReferenceO4.R1 Satellite Zeus will fly the Cannon camera to capture photos of near space. O4O4.R2 The camera on Satellite Zeus will be programmed ahead of time so that it will

work independently of all other electronics during the flight.O4

O4.R3 The HOBO datalogger will be a standalone item in the satellite that will measure the internal temperature, external temperature, and relative pressure.

O4

O4.R4 The HOBO datalogger information will then be used to determine the satellites position at certain times during the ascent and descent of the satellite.

O4

Requirements Objective 5 Requirements Level 1 ReferenceO5.R1 The electromagnetic generator will have magnets that vibrate across a copper coil

as the satellite vibrates, thus producing an electric current.O5

O5.R2 The created energy will then be held in a capacitor. O5O5.R3 The amount of energy in the capacitor will be constantly measured and recorded

by the data storage device on the microcontroller.O5

Requirements Objective 6 Requirements Level 1 ReferenceO6.R1 The electromagnetic generator will have magnets that rotate across copper coils

as the satellite rotates around the flight string, thus producing an electric current.O6

O6.R2 The created energy will be held in a capacitor. O6O6.R3 The amount of energy in the capacitor will be constantly measured and recorded

by the data storage device on the microcontroller.O6

Requirements Objective 7 Requirements Level 1 ReferenceO7.R1 After Satellite Zeus is retrieved, the data from the two generators will be uploaded

onto a computer for analysis.O7

O7.R2 The data results will be documented as a function of time and also in reference to the information retrieved by the HOBO datalogger so that the best results at the relative moments of the flight will be known.

O7

3.0 Design

3.1 Concept

Utilizing principles defined by modern electromagnetic theory, two generators on-board Zeus will produce electricity derived from the mechanical oscillations of eight neodymium magnets near a fixed copper coil per generator. The vibrations will move the magnets, inducing a magnetic flux across the copper coil, as described by Faraday's Law. The magnetic flux across the copper coil will drive a current. The force on the charges from the magnetic field will oppose the change in magnetic flux and drive the current in the coil, according to Lenz's law.

Zeus will feature two electromagnetic generators. One will harness the vibrational energy, the other with capture the rotational energy. Each will be connected to a separate electrical load that will be monitored by a microcontroller. The load seen by the generators will be in the form of a capacitor bank. The bank will have a limited capacity, thus will be monitored and emptied when


priceja, 10/08/10,

The HOBO doesn’t measure, it just records what the sensors measure


filled. Each time the bank is emptied the micro-controller will register the dump. This data will be used to calculate the total energy created. There are four components that will be considered in the model design of the vibrational generator: a magnetic field, a coil, a vibrating mechanism, and an electric circuit (or load). A coil made of copper will be set fixed to the frame of the spacecraft and inside a set of randomly oscillating magnets. There will be two sets of magnets, four square neodymium magnets of alternating polarity for each set, each placed near one side of the copper coil. The vibrating mechanism, in the form of spring metal, will support the bidirectional movement of the magnets, which together will create a magnetic flux when experiencing an acceleration of force. The ends of the coil will be connected to a circuit capable of accumulating the power generated, as well as manipulating the current as desired to support the objectives of the experiment. Rubber stoppers will be placed on the generator structure to limit the magnets oscillation by contact between rubber and magnet, thereby preventing damage to the magnets and structure. The rotational generator will use the same electric laws, but will have a different method of creating the moving magnetic flux. There will be eight copper coils a ranged in a circular pattern fixed to the body of the satellite. Above the coils there will be a free spinning disk with a pattern of magnets in the same configuration as the coils along the edge. The disk with spin with a semi-random motion in relation to the fixed coils creating the moving flux that then drives a current in the coils. The coils will be connected in parallel and then to a electrical load identical to that used by the vibrational generator.

For the duration of the flight, energy will be harvested from the local environment via the generators and stored into a custom designed capacitor bank. Diodes will be used to regulate the direction of a dynamic current flow produced by the generator. A rectifier will be implemented in order to ensure a single output polarity, as well as a direct current instead of an alternating current. A full-wave bridge rectifier is preferred, as it will is more efficient than a half-wave rectifier. The rectifier is to be designed with 4 diodes arranged in a “diode bridge” configuration that will feed the load. The load will be a single capacitor bank for each generator. A capacitor bank will be constructed by connecting ten tantalum capacitors is parallel. This construction technique is known as multi miniature capacitor bank, or MMC bank. A MMC bank was chosen partly because of the robustness of tantalum capacitor. Due to the fact that the MMC will be subject to low pressure and extreme temperature, it must be built to withstand a large amount of abuse. The other factor that determined the construction technique was the low capacitance of tantalums for their cost. Many small capacitors in parallel are much more cost effective when compared to a single high capacitance tantalum capacitor. To solve the issue of the generators possibly over charging the MMC and damaging it, the voltage will be constantly monitored. When it reaches a set point, the bank will be shorted and the energy stored will be dumped. When this occurs, the microcontroller will make note within the data timeline. A relay will be used to short out the MMC and dump the energy.

The data associated with the generator will be continuously recorded for the duration of the flight and stored on a separate data storage device. The information that will be stored onto the micro-controller will include the data from all of the sensors accept for temperature and humidity. Team Lightning Rod will analyze the temperature and humidity data using the HOBO’s “Boxcar” program and analyze the generator data using Mathematica. The team will also match data from both the HOBO and Microcontroller Data Storage on a single timeline and determine any existing correlations.


priceja, 10/08/10,

For example…

priceja, 10/08/10,

Is this because someone on your team has experience with Mathematica?

priceja, 10/08/10,

Do you have a system in place such that none of the energy recordings will be lost? I’m thinking if it’s vibrating a lot and the cap is close to full, if the data points are being taken too far apart you could lose some of the highest levels of energy because you will record a 0 when the cap is reset.How is the capacitor bank going to be emptied?


3.2 Plan

Team Lightning Rod ordered many of its necessary hardware components including magnets from Magnet4less.com, spring steel from McMaster.com, a microcontroller and a development board from SparkFun, and capacitors, relays, and switches, an LDO regulator, and a data storage device from mouser.com. Provided hardware from Space Grant and The ITLL consisted of aluminum tape, anti-abrasion washers, Canon camera, foam core sheets, heater, HOBO, hot glue, and plexi-glass. Items that still need to be purchased include: nine volt batteries, double A batteries, 30 gauge copper wire, machine screws, and rubber bumpers. Now that plexi-glass has been attained, Team Lightning Rod will cut the plexi-glass and form the basic structure of the two generators. After creating the structures of the generators, the plexi-glass will be attached to the machined spring steel using machine screws. The magnets will then be attached on the end of the spring steel, and the copper wire will be placed between the magnets. This will be the vibration generator for Zeus. Similarly to the vibration generator, plexi-glass for the rotational generator will be cut and magnets will be fixed into their respective locations. A bearing will insure that the generator is free to turn and will connect the two circles of plexi-glass housing magnets together. The generators will then need to be tested to make sure that the conceptual design works, and necessary alterations will be made to create as efficient of a generator as possible. The next system that will be created will be the structure of Zeus. To begin constructing the structure, Team Lightning Rod will cut foam core into the 2-dimensional cube pattern. Then, the 2-dimensional cube pattern will be transformed into a 3-dimensional cube. The holes for the string attachment will be cut and the string attachment will be added to the cube through two washers, a tube, and the paper clips. Testing of the cube’s durability will ensue with the Whip Test, Drop Test, and Kick Test. Once the structure is known to have a durable design, Team Lightning Rod will assemble all electronics according to the functional block diagram. Finally, the constructed project will be tested with a Cold Test and a vibration test to make sure that everything is insulated and working properly. The Team will then make necessary changes, place contact information and an American flag on Zeus, and then launch it.

3.3 Diagrams and Drawings



Would like to see how these two diagrams fit together. First one is interesting but should show what is coming into the analog ports for example.

priceja, 10/08/10,

This would be much easier to read in bulleted or table format as far as the hardware goes


Rotational Generator



Great drawings but need to have labels and dimensions would help.

priceja, 10/08/10,

Sensors attached to the HOBO?


Vibrational Generator

3D Isometric View



Unfolded View



Dimensions


2D Unfolded with Dimensions

4.0 Management

Team Lightning Rod will be managed by Trevor Luke. Each member holds a vital role in the project and all members will contribute to construction and finalization of the satellite Zeus and its components. Each team member is assigned a formal role and assistant duties to ensure that not only one person is working on each aspect of the satellite. Finalization of Zeus is estimated to occur two weeks before launch. All of the roles of team members are detailed in the charts given below:

4.1 Organizational Chart

NAME TITLE ADDITIONAL RESPONSIBILITIESJESSE ELLISON ELECTRONICS HEAD DRAFTING/DESIGNMATT HOLMES BUDGET HEAD PROGRAMMING ASSISTANT/

DOCUMENTATIONMATHEW DICKINSON

STRUCTURE CO-HEAD TESTING ASSISTANT

CHRIS BENNETT STRUCTURE CO-HEAD PRESENTATION COLLABORATORTREVOR LUKE TEAM LEADER TEAM SCHEDULING/

COMMUNICATIONS/ DOCUMENTATION

ALEX LOUIS TESTING HEAD FILMSUSHIANS RAHIMIZADEH

PROGRAMMING HEAD MISSION DESIGN


priceja, 10/08/10,

You need dimensions of everything, not just the box


ALL ALL TEAM MEMBERS WILL ASSIST IN EVERY ASPECT OF THE PROJECT.

4.2 Flow Chart

4.3 Schedule

Complete proposal and presentation and submit online—Due 9/16 by 7:00 amFill out order form and order hardware—9/23 at 11:30 Team meeting-10/4 at 3:00Cut out generator structures-10/4Wrap copper coils-10/4Write presentation-Due 10/5 by 7:00Team meeting-10/5 at 3:00 pmTest structure—10/5 to 10/8Assemble magnets and spring steel for vibrational generator-10/5Complete construction of vibrational and rotational generators—10/8Team meeting-10/10 at 2:00 pmTest and adjust generator design to optimize voltage-10/10Assemble and wire satellite—10/10 to 10/15Complete the wiring of satellite—10/16Team meeting-10/17 at 2:00 pmProgram satellite hardware—10/17 to 10/22Final Construction Completed—10/23Team meeting-10/24 at 2:00pmFinal Testing—10/24 to 10/29Project Finished—10/30Buffer Week—10/31 to 11/5Finish Critical Design Review-11/2Launch—11/6



Yeah, your formatting could be better.

priceja, 10/08/10,

Easier to follow in a table


Write final presentation-11/30Finish Analysis and Final Report- 12/4Team video due-12/4

5.0 Budget



6.0 Test Plan and Results

Prior to the flight, team Lightning Rod will test the payload to make sure that it will convert the kinetic energy from the vibrational and rotational motion to electrical energy. These tests will consist of shaking the generators and simulating the real life events the satellite will experience on its flight. The generators will be attached to an oscilloscope, which will determine if the generator will produce a significant amount of energy from motion. After the team determines that the generators will work, Team Lightning Rod will test the integrity of the satellite and its ability to withstand extreme temperatures and collisions. For the cold temperature testing, the team will place the balloon satellite and the payload into a cooler of dry ice and let it sit there until it reaches a temperature of -80 degrees Celsius, which to what it is expected to be at an altitude of 30 km. The dry ice will be handled with gloves and tongs, and will be contained in a styro-foam chest with a loosely fit lid. To test its ability to withstand collision, the test team will subject the prototype structure to a battery of tests that will simulate its descent after the balloon


priceja, 10/08/10,

Are you going to turn your payload on? This is the purpose, to make sure that everything works with just your heater

priceja, 10/08/10,

What will you do if they don’t produce enough energy?


pops. For these tests, the team will fill the balloon satellite structure with rocks to replicate the weight of the actual satellite. The test team will do a whip test, in which the team will attach the prototype to a string, similar to the one used on launch day, and swing it around in circles. This will test both the ability of the structure to endure the whipping motion after burst as well as the structures ability to maintain a good hold onto the flight rope. The team will make sure that the swinging will be directed away from any person and in a secluded environment. In performing this test, the team will vary the length of the string to determine the satellite’s ability to grip the string as acceleration changes. The test team will perform a series of drop tests. In these tests, the team will drop the structure from varying heights to determine if the satellite will withstand the ground collision on landing. The test team will also conduct a series of drop tests with the satellite payload included to examine the affects of violent forces on the generators. From these tests, the team will analyze the structural weaknesses of the satellite and fix them before launch day. The testing team will also test the camera to make sure that the timing chip is operating properly. The first test will be at room temperature. The team will place the camera on a table and turn on the timing chip to make sure that it works without additional parameters. Then the team will also test the camera’s ability to take pictures in a cold environment. The team will place the camera in a cooler of dry ice to simulate the temperatures experienced at 30 km above sea level, minding the safety precautions that may accompany the handling of dry ice. After testing the structural integrity of Zeus, the electronics and programming heads will conduct a series of functional tests. These tests will evaluate the payload’s ability to operate as an integrated system. The first of the functional tests will be done under stable electrical conditions to see if the system can operate for 120 minutes, which is 30% longer than expected flight time. Then the system will be tested under low and high voltage conditions. Each test that involves the payload in any way will be subject to a test of the data retrieval abilities of the system. The structure team will collect the data from these tests and analyze it to determine necessary adjustments in the structures design.

7.0 Expected Results

Team Lightning Rod expects to have a very large amount of data to interpret results from. First, it is expected that the vibrational generator will generate a measurable amount of power. The data acquired will be matched to that of an external accelerometer to verify the power generated. We expect similar results from the rotational generator but possibly more power harvested. The voltages on the capacitor banks for each of the generators will be measured by the microcontroller every second. Team Lightning Rod expects that there will be an increase in the power generated when the balloon passes through the more turbulent parts of the atmosphere. The vibrational generator will generate a peak amount of power just after burst, it is expected. The performance of the generators should be semi impervious to environmental factors. One possible effect would be that of the temperature. There might be a slight power increase when the temperature is at its' lowest due to a decrease in the resistance of the copper wire in the coils and thus less energy lost to heat.


priceja, 10/08/10,

This is the first mention of an accelerometer, how does it fit in?

priceja, 10/08/10,

What does this mean, do you have a general number?

priceja, 10/08/10,

If you’re doing these tests with your payload and the structure is weak, what happens if your payload breaks? Have you built time into the schedule for any rebuild/repair time?

priceja, 10/08/10,

Will the mass be distributed and attached in the same manner as you anticipate that your real components will be?

Documents

Requirements Flow Down - University of Colorado … · Web viewA full-wave bridge rectifier is preferred, as it will is more efficient than a half-wave rectifier. The rectifier is