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EXECUTIVE SUMMARY Model Rocketry has
been around since humans discovered black powder. The Chinese were the first
to create an actual “rocket”. This happened back in the 13th century when
they converted fireworks into weapons of warfare. Today however model
rocketry is considered a hobby. The
prompt for our project came when Peter Semig of
Texas Instruments, came to us with a story. This story involved Pete’s boss
who is an active hobbyist in large scale model rocketry. Apparently his boss
had spent months designing and crafting a large model rocket. When the
launch day came and he launched his rocket, the parachutes did not deploy.
This turned the rocket virtually into a missile which “crashed and burned”
once it came back down to earth. Hence our problem was presented. Pete’s
boss proposed that he have us engineers at MSU design an Electronic
Parachute Deployment System using Texas Instruments products. Our objectives were then made clear.
We were instructed to design an electronic parachute deployment system that
would incorporate a TI-MSP430 microcontroller that utilized an Altimeter and
Accelerometer to deploy the rocket’s parachutes without failure. These would also be used to record real
time data to serve as a second purpose. Our design would
incorporate our circuit into a large scale model rocket. The rocket is
designed to have a two stage parachute deployment system. Our circuit, which
will be placed in the middle of the rocket shaft between both parachutes,
with be programmed to speak to the altimeter and accelerometer. The
accelerometer will be used to deploy the first parachute; once it reads zero
g-forces after the rocket reaches apogee, the circuit will send a current to
a charge deploying the first parachute. The altimeter will be used to launch
the main parachute and will send a current to a second charge once on decent
it reads a set altitude. We have to account for pressure and temperature factors to keep our circuitry functioning correctly. To do this we will be placing out components in heat resistant foam padding. This will ensure durability. We consider a successful project outcome to be a successful deployment of both parachutes at the correct points of flight to ensure the rockets safety. Also the circuit must be reliable for at least 20 launches. |
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Contents
Introduction
Rocketry is a popular hobby for many
people that can range from a fun educational activity for children to a highly
technical recreation for enthusiasts. Model rocketry has been a popular hobby
in the United States for over 50 years with such organizations as The National
Association of Rocketry, founded in 1957, which helps to promote the continued
education and practice of hobby rocketry. Model rockets follow the basic
principle of staging a flight, lift off by force of a
propellant, and a retrieval system. The scope of this project is to design an
electronic based retrieval system for a large-scale model rocket. Texas
Instruments has sponsored this design team with the problem of employing an
electronically deployable parachute system (EPDS) to replace the basic timed
charged system used in most model rockets today. Texas Instruments has set up
the criteria that this system be implemented by way of a fabricated Printed
Circuit Board (PCB) consisting of an accelerometer, altimeter, and LCD. These
components will communicate with a MSP430 LaunchPad
and microcontroller, later be tested, and finally- fully integrated into a
model rocket. This design must account for the deployment of two parachutes in
the retrieval process that will be governed by the sensors and MSP430
microcontroller to successfully bring a model rocket back from flight.
Background
Model rockets have a range of classes
from A – Z. Each class is specified by the capabilities of the rocket such as
weight, propellant payload, max height, and impulse. Classes
H – Z are classified as high
power rockets and will not be considered within this project due to the need
for government regulated licensing for safety. Class G rockets however have the
highest rated capabilities of model rockets that require no special license and
will be considered for this project.
Class G motors have an average thrust
of 18 pounds (80 Newton’s). It uses a unique composite fuel which is three
times more powerful than conventional black-powder rocket motors. This equates
to a total impulse around 137 Newton-seconds, and a maximum life off weight of
20oz. This is more than enough thrust, and will be perfect for our large scale
testing. Also these motors are rated up to 1000ft on the clearest of days,
which is just below regulated rocket heights.
Most
model rockets rely on a 'timer based' system that deploys a charge at a point
in the rocket's flight based on the amount of propellant and 'delay' added to
the payload. This system is relatively dependable in most circumstances for
clear, low wind flights, and small rockets. As model rockets become larger and
weather conditions become less ideal, the timer based system becomes less
dependable. This project proposes a lightweight, reliable, and integrated PCB
design that will remove the 'guess work' from hobby rocketry.
Electronic
parachute deployment systems are not ground breaking technology but are nearly
non-existent in amateur rocketry. Most highly technical retrieval systems are
seen by high power rocket enthusiasts in expensive and weighty designs. This
project aims to create a lightweight and low cost electronic based retrieval
system that can be used by rocket enthusiasts of any level, and create a
detailed and repeatable process for production.
Mission Statement:
To
produce a cost effective and lightweight working PCB component to interface
with a TI MSP430 micro controller that would electronically deploy parachutes
in two phases to safely bring a model rocket back to the ground.
1.
Build
relationship with Texas Instruments and clearly define concept of project
2.
Produce
conceptual solution and initial design for PCB circuit
3.
Establish budget
criteria, order parts, and create proto-type
4.
Test proto-type
and implement changes
5.
Optimize weight
of component and integrate to MSP430 micro controller
6.
Full integration
into model rocket and final testing
_files/image002.png)
Problem Specifications:
·
Must develop a “BoosterPack” that is compatible with a TI MSP430 MC
·
Booster Pack must
utilize accelerometer, altimeter, and LCD with real time data
·
Booster Pack must
be integrated to the MSP430 MC to deploy parachutes in two phases.
o
1: Initial
stability parachute at peak of launch.
o
2: Secondary
parachute at defined altitude for final descent
·
Project must meet
$500 budget + T.I. stipend and be deliverable by Design Day (December 6, 2013)
Conceptual
Design
For this project we had to base our design on
practicality. We want our finished product to be used by actual large scale
model rockets. With that in mind, we started with what we knew. The heart of our
project is the MSP430 control chip (Figure 1). It will be directing the
functions of our designed PCB board. Our PCB board base will be designed using
a booster pack, which will consist of an Accelerometer, Altimeter, and other
circuit components. These components in turn will be controlling the actions of
the rockets parachutes.
_files/image003.png)
(Figure 1)
For large scale model rockets, there
are many designs that engineers have come up with over the last few hundred
years. After researching many designs we decided on a dual parachute design
that we will implement our circuit in. Before you can grasp how our circuit
will work in the rocket however you must first understand the design of the
rocket itself. Large model rocket bodies are made up of six separate parts. Starting
from the top of the rocket and moving down in sections, first there is the
“Cone” or top of the rocket. The only function of the cone is for aerodynamic
purposes of flight path. Second (optional) is the “Payload” bay which is an
empty bay where you can place any random items of choice. Third there is the
“Drogue Parachute” bay. This bay holds the drogue parachute and its charge. The
drogue parachute is considered the primary parachute which will be the first to
deploy. Fourth there is the “E-bay” or electronics bay. This is where our PCB
board will be placed. Next is the “Main Parachute” body. Like the drogue bay
the main parachute bay holds the main parachute and its charge. Lastly there is
the base of the rocket. The base holds the rocket motor, and has the
directional “Fins” attached. This is all shown in Figure 2.
_files/image005.jpg)
(Figure 2)
Now that you are familiar with the
rockets design you will be able to better understand the role our circuit will
play in the parachute deployment system. We designed a rough block diagram of
our circuit system that is shown below in Figure 3.
_files/image007.jpg)
(Figure 3)
As
displayed in Figure 3, the PCB (BoosterPack) will be
connected to a power supply of some sort and the altimeter and accelerometer
will integrated into the board. They will be measuring the altitude and
acceleration of the rocket in flight. This information will then be relayed to
the MSP430 and recorded. The altimeter and accelerometer will both serve
secondary proposes aside from recoding flight data. The accelerometer will not
be measuring the rate of change of velocity. It actually measures acceleration
associated with weight experienced by any test mass at rest. So for example if
the accelerometer is at rest on the surface of the earth it will read g= 9.81
(m/ s²), while in free fall it reads g= 0 (m/s²). So for its second purpose
when the rocket reaches apogee (highest point) then starts to go into free fall
(g= 0 (m/s²)) it will send a current to the primary charge which will deploy
the Drogue parachute as shown in Figure 4 below.
_files/image009.jpg)
(Figure 4)
This
drogue parachute is meant to let the rocket fall fast initially so it doesn’t
travel far from the launch site. Once the rocket falls to a certain altitude,
say 100-300ft or so, the altimeter will come into play. When the altimeter
measures the set altitude we program into the MSP430 it will then send a
current to the secondary charge to ignite it and deploy the main parachute.
This is its secondary purpose aside from measurements. This can be seen in
Figure 5 below.
_files/image011.jpg)
(Figure 5)
The main parachutes purpose is to slow the decent of
the rocket to a safe speed so that it doesn’t take damage upon landing.
To conclude, we are very confident
in our conceptual design. This design has a strong structure and of course will
have to be tweaked along the way in the coming weeks. However with the research
we have done we shouldn’t have any problems coming up with a PCB that will
support our concept.
Risk Analysis
After conducting research, and preliminary analysis, several technical challenges and non-technical concerns arose. These concerns stem from the need for dual parachute employment; protection of interior components & electronics; and perhaps most importantly, compliance with governmental regulations.
Technical
Considerations
Preliminary research on model rocket design immediately revealed the significance of dual parachute deployment. Without a dual parachute system in place, upon reaching apogee, the main parachute would deploy while the rocket begins its descent at terminal velocity. More than likely, the large surface area of this parachute falling at terminal velocity would lead to it being ripped apart. This outcome reiterates the initial problem which is seeking to be solved. The drogue parachute (also known as a streamer) remedies this situation. This parachute is more elongated, and therefore has smaller surface area to lessen drag. At apogee, the accelerometer will sense 0 G conditions and deploy the drogue parachute. Upon deployment, the drogue will slow the speed of descent. Due to its elongated shape and smaller surface area, drag will not be a factor. Additionally the drogue allows the rocket to return relatively close to its launch location (The goal here around 15 ft.)
The next consideration involves
protecting the rocket’s electronic components, and other interior components
from the high heat and pressure which will be experienced within the rocket
chamber during launch. The high heat during launch has the potential to melt
the parachutes, again the initial problem resurfaces. This potential problem is
combatted by the use of bulkheads surrounding the electronics bay. The
bulkheads are rimmed disks which serve two purposes. They connect the different
sections of the rocket together and also serve as protection to the internal
components like our circuit, parachutes, and other charges. Our bulkheads will
be made from aluminum ensuring the highest durability with the lightest weight
which is essential for our circuit protection and our rocket weight
restrictions. In addition to the bulkheads our circuit will secured inside of
the e-bay with fire resistant foam padding. This will ensure vibration and head
protection for our circuit.
Another method of protecting interior components is the use of recovery wadding (Please See Figure 6), a material very similar in appearance to tissue paper, which will be stuffed within the rocket to insulate the chamber, and especially the parachutes from heat.
_files/image013.jpg)
Figure 6
Non-Technical
Considerations
Proper compliance with governmental regulations will play a large role in the success of this project, particularly when it is time to test the proposed design by launching. The Federal Aviation Administration (FAA) governs all use of the sky through the use of radar towers. Rockets that fall in the category of classes 2 & 3 (High Power & Advanced High Power, respectively) require special licenses, as they are no longer considered amateur rocketry. Filing for the respective licenses of rocketry above Class 1 and awaiting approval for launch is out of the scope of this project, as doing so could easily take longer than the course one academic semester. Therefore, the designing of the EPDS must follow Class 1 certification, and therefore coordinate with the following FAA regulations:
(a) Class 1—Model Rocket means an amateur
rocket that:
(1) Uses
no more than 125 grams (4.4 ounces) of propellant;
(2) Uses a slow-burning
propellant;
(3) Is made of paper, wood, or
breakable plastic;
(4) Contains no substantial metal
parts; and
(5) Weighs no more than 1,500
grams (53 ounces), including the propellant.
Steps must also be taken to ensure that the chosen launch site of this project complies with local East Lansing city code and ordinances.
Project Management
The EPDS project team is made up of five members, all of which will contribute to the technical design aspect of this project. In addition, each of the members have been assigned a non-technical role to contribute to the intangible aspects of the project
Team Members & Non-Technical Roles:
·
Project
Manager – Tayloire Thomas
·
Presentation
Preparation – Kyle Christian
·
Document
Preparation – Moses Jones
·
Webmaster
– Ian McCall
·
Lab
Coordinator – Ryan Lupinski
In addition to defining non-technical roles, the project team has developed a Gantt chart to better manage the phases of the design process, the work breakdown structure, and most importantly – deadlines. The main phases of the EPDS project were defined at the onset of the project by the team’s sponsor (and customer), Texas Instruments. These phases are as follows:
· Phase I : Develop boosterpack for the MSP430 LaunchPad
o BoosterPack will be equipped with an accelerometer and altimeter to detect acceleration/velocity and altitude.
o BoosterPack will also be equipped with an LCD display to report real-time data
o Simulate designs in TINA-TI
o Design printed circuit board layout in PCB Artist
· Phase II: Integrate BoosterPack and MSP430
o Program algorithms within MSP430 which will communicate with LaunchPad
o Mount PCB and wiring within rocket
· Phase III: Testing
o Launch functioning EPDS-equipped rocket
o Recover rocket for future use
Please see APPENDIX
A for the team’s Gantt chart.
Budget
|
Product |
Provider |
Cost |
|
MSP 430 Launch Pad |
Texas Instruments |
$0 |
|
Digital Altimeters |
Digi-Key |
$8.28 |
|
Analog Altimeters |
Digi-Key |
$15.66 |
|
Analog Accelerometers |
Digi-Key |
$29.78 |
|
PCB Fabrication |
Advanced Circuits |
$33.00 each (x3) …
$99.00 |
|
Madcow Torrent Rocket |
Apogee Components |
$133.45 |
|
Pratt Hobbies GO-BOX Electronic Launch Controller |
Apogee Components |
$39.99 each (x1) …
$39.99 |
|
Cesaroni 1-Grain G46 Motor |
Apogee Components |
$23.75 each (x3) …
$71.25 |
|
MISCELLANEOUS FEES: Hazardous Materials Shipping Fee (from
Motors) |
$28.00 |
|
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Tentative Budgeted Amount $425.41 |
||
APPENDIX A: Gantt Chart
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Task
Mode |
Task
Name |
Work |
Duration |
Start |
Finish |
|
Manually Scheduled |
Electronic Deployable Parachute Project |
0 hrs |
58 days |
Wed 9/4/13 |
Fri 11/22/13 |
|
Manually Scheduled |
Project Definition
Phase |
0 hrs |
15 days |
Mon 9/9/13 |
Fri 9/27/13 |
|
Manually Scheduled |
Initial Group
Meeting |
0 hrs |
1 day |
Tue 9/10/13 |
Tue 9/10/13 |
|
Manually Scheduled |
First
Sponsor/Facilitator Meeting |
0 hrs |
1 day |
Thu 9/12/13 |
Thu 9/12/13 |
|
Manually Scheduled |
Research / Pre-Proposal
Phase |
0 hrs |
27 days |
Thu 9/12/13 |
Fri 10/18/13 |
|
Manually Scheduled |
Group Meeting
(Develop: Block Diagram & Pre-Proposal) |
0 hrs |
1.5 days |
Tue 9/17/13 |
Wed 9/18/13 |
|
Manually Scheduled |
Block Diagram for TI
Due |
0 hrs |
0 days |
Thu 9/19/13 |
Thu 9/19/13 |
|
Manually Scheduled |
Pre Proposal Due |
0 hrs |
0 days |
Fri 9/20/13 |
Fri 9/20/13 |
|
Manually Scheduled |
Voice of Customer
Assignment Due (Motter) |
0 hrs |
0 days |
Mon 9/30/13 |
Mon 9/30/13 |
|
Manually Scheduled |
Get familiar w/ PCB
Artist & TINA software |
0 hrs |
11 days |
Thu 9/19/13 |
Thu 10/3/13 |
|
Manually Scheduled |
Develop
"Practice PCBs," |
0 hrs |
22 days |
Thu 9/19/13 |
Fri 10/18/13 |
|
Manually Scheduled |
Revise Pre-Proposal,
Develop Final Proposal |
0 hrs |
16 days |
Fri 9/20/13 |
Fri 10/11/13 |
|
Manually Scheduled |
Final Proposal
Due (Asmussen, TI & Grotjohn/Udpa) |
0 hrs |
0 days |
Fri 10/11/13 |
Fri 10/11/13 |
|
Manually Scheduled |
Team Oral
Proposal Presentation |
0 hrs |
0 days |
Fri 10/11/13 |
Fri 10/11/13 |
|
Manually Scheduled |
Create Budget
/Determine Parts List |
0 hrs |
2 days |
Fri 9/20/13 |
Mon 9/23/13 |
|
Manually Scheduled |
Order Parts |
0 hrs |
2 days |
Mon 9/23/13 |
Tue 9/24/13 |
|
Manually Scheduled |
Contact Jackson
Michigan Rocket Club… Possibly attend launch |
0 hrs |
26 days |
Mon 9/16/13 |
Sat 10/19/13 |
|
Manually Scheduled |
Phase 1: Develop BoosterPack for
MSP430 LaunchPad |
0 hrs |
31 days |
Thu 9/19/13 |
Thu 10/31/13 |
|
Manually Scheduled |
Develop designs for
Boosterpack, simulate in TINA |
0 hrs |
23 days |
Thu 9/19/13 |
Sat 10/19/13 |
|
Manually Scheduled |
Make several designs
using different altimeter sensors to find best fit, and also to ensure
flexibility in the future (Analog & digital altimeters) |
0 hrs |
6 days |
Wed 10/16/13 |
Wed 10/23/13 |
|
Manually Scheduled |
Convert BoosterPack designs from TINA to PCB Artist (Check with
Pete Semig & Mike Mock to double-check ) |
0 hrs |
3 days |
Wed 10/23/13 |
Fri 10/25/13 |
|
Manually Scheduled |
Send PCBs to
fabrication |
0 hrs |
5 days |
Fri 10/25/13 |
Thu 10/31/13 |
|
Manually Scheduled |
Phase 2: Integrate BoosterPack & MSP430 |
0 hrs |
11 days |
Fri 11/1/13 |
Fri 11/15/13 |
|
Manually Scheduled |
Size/Weight
Reductions (if possible!) |
0 hrs |
8 days |
Fri 10/18/13 |
Tue 10/29/13 |
|
Manually Scheduled |
Final Integration |
0 hrs |
16 days |
Wed 10/30/13 |
Wed 11/20/13 |
|
Manually Scheduled |
Assembly of rocket
chamber |
0 hrs |
24 days |
Wed 11/20/13 |
Mon 12/23/13 |
|
Manually Scheduled |
Placement of
electronics in E-bay |
0 hrs |
1 day |
Sun 10/20/13 |
Sun 10/20/13 |
|
Manually Scheduled |
Parachutes connected
to charges |
0 hrs |
1 day |
Sun 10/20/13 |
Sun 10/20/13 |
|
Manually Scheduled |
Charges connected to
PCB |
0 hrs |
1 day |
Sun 10/20/13 |
Sun 10/20/13 |
|
Manually Scheduled |
Testing and Simulation |
0 hrs |
3 days |
Thu 11/21/13 |
Sun 11/24/13 |
|
Manually Scheduled |
Team Design Issues
Paper |
0 hrs |
18 days |
Wed 10/30/13 |
Fri 11/22/13 |
|
Manually Scheduled |
Individual
Application Notes Due (Asmussen) |
0 hrs |
0 days |
Thu 11/7/13 |
Thu 11/7/13 |
|
Manually Scheduled |
Launch Rocket |
0 hrs |
1 day |
Fri 11/22/13 |
Fri 11/22/13 |
|
Manually Scheduled |
Retrieve rocket,
record results |
0 hrs |
1 day |
Fri 11/22/13 |
Fri 11/22/13 |
|
Manually Scheduled |
Download flight data
(Acceleration, altitude) for future presentation |
0 hrs |
2 days |
Fri 11/22/13 |
Sun 11/24/13 |
|
Manually Scheduled |
End Game |
0 hrs |
11 days |
Fri 11/22/13 |
Fri 12/6/13 |
|
Manually Scheduled |
Demonstrate Project
Prototype (In Class) |
0 hrs |
3 days |
Mon 11/25/13 |
Wed 11/27/13 |
|
Manually Scheduled |
Final Reports Due |
0 hrs |
0 days |
Wed 12/4/13 |
Wed 12/4/13 |
|
Manually Scheduled |
Design Day |
0 hrs |
0 days |
Fri 12/6/13 |
Fri 12/6/13 |
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