Stabilized Experiment Platform for Near Space Research

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Stabilized Experiment Platform for Near Space Research

Abstract: Many universities, private, and government organizations regularly conduct near space research

using weather balloons as an inexpensive means to reach the upper atmosphere. A stabilized platform

attached to the weather balloon would greatly broaden the types of science payloads carried on-board for

atmospheric scientists and other researchers. This project focuses on the development of a platform thatcan be oriented in a selected direction and maintain that direction for the duration of the experiment by

compensating for the motion of the balloon and any other attached payloads.

Introduction: The NevadaSAT program at the University of Nevada, Reno provides a test platform for

students and other members of the academic community to perform research in the upper atmosphere.

The current NevadaSAT launch configuration consists of a weather balloon connected to a parachute

followed by the communication and science/student payloads, all connected by string. Using string to

connect to the anchor (balloon) allows a prohibitively high rotation rates (over 360/sec) and pitch angles of

up to 45 (Poe, 2008), thus restricting the types of experiments possible to experiments that either sample

very fast (camera) or are direction-independent. A stabilized platform that compensates for the rotation andswing of the payloads would allow experiments requiring a measuring device, camera, or antenna to be

oriented in a specific direction to be conducted. Atmospheric scientists commonly collect data in two ways;

by using aircraft and weather balloons to collect atmospheric samples and by using satellites to view the

production of greenhouse gasses and measure solar radiation reflected off the Earth. By attaching a

payload with sensors, that are normally restricted to satellites, to a weather balloon atmospheric scientists

could collect all the necessary data in one experiment. Atmospheric scientists that track the production of

greenhouse gasses would benefit the most from a less expensive alternative to satellites that they could

conduct entirely themselves.

A previous attempt to build a stabilized platform for balloon based experiments was done by UNR Masters

student Blake Poe. His stabilized platform was able to orient to 23 of the selected direction with a greatly

reduced rotation rate and pitch angle than is typically experienced in a balloon flight. Poesmethod used

two motors and a gimbal structure to counter the motion of the balloon, thus maintaining the desired

orientation. The platform was anchored to the balloon by a single string which greatly complicated the

system (as noted previously) by not providing a reactive mass for the induced torques of the motors.

This project will attempt to create a stabilized platform capable of meeting the previously set design

requirements while operating in the actual conditions found in a typical balloon launch.

Instead of controlling the reactive motion with motors, the proposed method is to rigidly attach to the

balloon. The balloon has a significantly larger moment of inertia than the proposed payload and is a very

effective reactive mass. Being able to react against the balloon allows the use of a powered gimbal deviceto better compensate for the motion of the balloon.

Objective: This project will improve upon the design requirements outlined in Poes Masters thesis while

subject to the actual rotation rate and pitch angle of a typical balloon flight. The payload shall maintain 15

from desired azimuth and elevation, capable of 360/sec spin rate (all axes), total mass of less than 3 kg,

and operate at an external temperature of -60C. This project will have three key milestones. First, the


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construction and field testing of a sensor payload capable of measuring the motion of the balloon during a

typical balloon launch. Second, design and construct a platform capable of operating within the constraints.

Finally, using the stabilized platform, develop a control algorithm to meet the design requirements.

Plans for Research: The three key milestones are divided into smaller tasks as described below.

Balloon Motion Sensor Payload: The sensor payload will have an onboard microprocessor, six-axis

gyroscope/accelerometer, digital compass, data logger, GPS, and a motor to put a torque on the balloon.

The sensor payload will then be flown on multiple balloon missions to collect data. This milestone will be

broken up into the following subtasks:

1) Research components to find those suited for high altitude deployment and meet accuracy requirements.

2) Construct a housing to rigidly attach to the balloon and protect the other components.

3) Conduct test flights with measuring device.

4) Write a computer program that can interpret data and determine the design constraints.

Stabilized Experiment Platform Construction: Once the design constraints are known, the designing and

construction of the stabilized experiment platform will begin. This second milestone is broken in thefollowing subtasks:

1) Create a test platform capable of replicating flight conditions in the laboratory.

2) Design and construct a prototype capable of meeting design constraints and design requirements.

Control Algorithm Development and Testing: Using the developed stabilized platform, the control system

can be developed to accurately and efficiently maneuver the stabilized platform to maintain a desired

orientation. This task is split up into the following subtasks:

1) Design control algorithm for controlling platform motion.

2) Test platform in lab, and tune as necessary to meet design criteria.

3) Conduct test flight(s) on actual balloon mission.

Timetable:

Construct payload to measure balloon motion: AugustSeptember 2012

Collect data of balloon motion: September 2012

Design platform, build platform: NovemberDecember 2012

Develop and optimize platform controller: JanuaryFebruary 2013

Laboratory Testing of Prototype: FebruaryMarch 2013

Flight Testing: MarchApril 2013

Compile and Disseminate Results: May 2013

Plans for Dissemination of Results:This work will be presented at the GURA symposium and have a

poster displayed on the University of Nevada, Reno Campus.

Qualification of Student:Worked in Engineering Robotics Lab for 18 months and has constructed 20+

payloads and participated in 12 balloon launches. Previously conducted research by student has provided

experience with microcontrollers and necessary programming skills for this project. Students emphasis in

dynamics and aerodynamics in coursework will aid in designing of prototype.


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Budget:

MicrocontrollerPayload will require a microcontroller to perform all in flight calculations and control servos.

$200

Platform Construction MaterialThe platform will need to be robust enough to protect components from multiple landings and the

low temperatures of the upper atmosphere. The frame will be constructed mainly from aluminumand insulating foam.

$200

ServosThe platform will require servos to move the payload to counter the motion of the balloon andattached payloads.

$100

SensorsThe platform will require a 3 axis gyroscope, 3 axis accelerometer, and GPS.

$200

Electrical EquipmentThe platform will require electrical components such as a max stream radio, batteries and basicelectrical components (wire, resistors, ect.).

$300

Parachutes

The payload will need a parachute to control the rate of descent after the balloon pops.

$100

Weather BalloonsWeather balloons filled with be used to carry and test the payload.

$200

HydrogenUsed to fill weather balloons.

$100

GasolineFor transportation to launch and landing locations

$100

Total $1500


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April 5, 2012

To Whom It May Concern:

I wish to express my strong endorsement for the application of Andrew Smith, who seeks a supportunder the UNR GURA program. Mr. Smith is pursuing a B.S. degree in Mechanical Engineering and I am

very eager to support his application for this opportunity and honor, and contribute to his success in this

proposed endeavor. I have known him since 2010, when he began involvement in extracurricular high-

altitude ballooning activities. Since then, he worked with me on a GURA research project on the use of

Dropesondes (small airborne sensors dropped from aircraft to measure the weather) in parachute research.

Additionally, he has been employed to assist in our related ballooning research. He is planning to attend

graduate school here at UNR, and he would be an excellent choice for a GURA award.

Mr. Smith is a non-traditional student in that he comes from a successful (and continuing in the

National Guard) military background. He is pro-actively working to gain research experience to better

prepare him for advanced study in graduate school, in similar areas of research. Over the past two years,

Andy has increasingly impressed me with his developing skills, his leadership abilities, and his personal

ambitions to do quality work on problems of significance. I have quickly come to expect more and morefrom hima quality that will serve him well as he progresses.

The specific project which Mr. Smith is proposing has potential applications in numerous areas

involving remote sensing from airborne and spaceborne platforms. Over the past year of working in our

group, he came to become familiar with the M.S. thesis topic of a former student, and has formulated a set

of good ideas on how to improve upon the prior art of low-cost stabilized instrument platforms on

balloons. I have read and agreed to this proposal, which is solely his idea and will be his responsibility to

develop. I pledge to continue to serve as research advisor, provide access to the necessary laboratory and

field equipment needed to support his work, and to facilitate his interactions with the broader technical

community in this area (such as through the American Institute of Aeronautics and Astronautics, AIAA).

I strongly support Andy Smith and his proposal of this project to GURA program. His skills,

combined with his strong work ethic, will make this scholarship an ideal vehicle to recognize hisachievements and further encourage and prepare him as he advances towards the professional world. I

commit myself to assisting him through this process with both my time and the resources I have available

in my laboratory.

Sincerely,

Jeffrey C. LaCombe

Associate Professor of Metallurgical and Materials Eng.

University of Nevada, Reno

P.S. If I may be of additional assistance in this matter, or if you have any further questions, please do not

hesitate to contact me. My phone number is (775) 784-1797, and I can also be reached via email at

[email protected].


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College of EngineeringUniversity of Nevada, Reno

College of Engineer

University of Nevada, Reno/

Reno, Nevada 89557 -0

(775) 784-6931 of

(775) 784-1701

http://www.engr.unr.edu/

Department of Mechanical Engineering/312College of Engineering

DATE:April 5, 12

TO:General Undergraduate Research Award (GURA) Selection Committee

FROM:Eric L. Wang, Associate Professor

RE:Recommendation for Andrew Smith

This is a letter of support for Andrew Smiths General Undergraduate Research Award(GURA) application. If he is awarded the grant, I agree to mentor and support Andy to

maximize the likelihood that he completes the proposed research project entitledStabilized Experiment Platform for Near Space Research. I will make the equipment

necessary to complete this project available for Andys use.

I have known Andy for about three years as his instructor in 3 courses and through hisparticipation in several Nevada Space Grant activities and previous GURA and EPSCoR

research projects. Last year, Andy wrote and received a GURA grant and more thanexceeded my expectations. His work ethic and quality of work has made him a prime

recruit for graduate school (he has already stated his intention to stay at UNR for his MSdegree). While his GURA project last year was in support of one of my Doctoral

students research, this year Andy is proposing to work on a topic that can easily becomethe basis for his own graduate (MS) research once he graduates (expected May 2013).

I have mentored one previous GURA recipient, Gabe Herz (2009-2010 GURA recipient)

am currently co-mentoring both Andy and Shandor Korda. Of the three students, Andy isby far the best. I strongly feel that Andy will make an excellent recipient of a GURA. The

scope of the proposed project is both reasonable and academically challenging.

Sincerely,

Eric L. Wang, Ph.D.Associate Professor, Mechanical Engineering

University of Nevada, [email protected]

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Stabilized Experiment Platform for Near Space Research