Eclipse Ballooning Project - WordPress · Eclipse Ballooning Project Team: Abigail Sydnes, ......

Senior Design II, Slide 1

Eclipse Ballooning Project

Team: Abigail Sydnes, Dmitriy Yarmaliuk, Edward

MacMurchy & Michael Mazzanti

Faculty Advisor: Dr. John J. Helferty

The Parliament


Introduction


Iridium Modem communicates

with ground laptop via Internet

and satellite communication.

Video payload and ground station

communicate using Ubiquiti

Rocket M5 Modems.

OCCAMS Cut Down payload

receives commands from

Iridium Modem.

Introduction


Reliable means of video capture

Sensor and Tracking data from full

launch

360° Video Capture Capability

Extensive testing to guarantee

project success

Introduction - Proposed Deliverables


Problem Statement


Problem Statement

Launch Date: August 21, 2017

Trigg County High School, Cadiz, Kentucky

Test Launch: April 11, 2017

Roundtop Mountain Resort Lewisberry, PA

Purpose

Stream stable, targeted video of solar eclipse to

the NASA Stream website for entirety of

event

360° Video Camera recording entire flight

Coordinate nationally with other schools to

make recording of historic eclipse


Design Constraints


Design Constraints

Maximum weight of HAB (including

2000 gram balloon) of 12lbs.

Environmental temperatures as

low as -55°C.

Robust payload design able to

pass through jetstream

unscathed.

Launch location avoiding any

inclement weather. Additionally,

avoidance of any airports or

similar restricted airspace.


● Weight Requirements

○ 12 lbs maximum system

weight, including balloon

○ 6 lbs maximum payload item

weight

● 2 methods of flight termination

● Notify FAA between 24 h and 30 m

of launch

Safety and FAA Regulations


Evolution of Design


Evolution of Design - Montana State University Workshop


Evolution of Design - Inclusion of 360° Camera

On top of having a streamed

tracking video, a 360°

video would provide a full

environment view upon

recovery of the HAB.

Mounting options and low

weight (7 oz) of 360°

camera allow for easy

inclusion in any payload

design.

In the event of complications

with video payload

streaming or tracking,

eclipse is guaranteed to

be captured.


Evolution of Design - Removal of Still Image Payload

Weight of payload prevented additional devices from

being added without surpassing 12lbs.

Live video feed along with still images would be

redundant.

Quality of streamed video is slightly lower in

resolution.

Video payload stores camera feed on-board and

uninterrupted video may be obtained after recovery.

360° video camera Nikon KeyMission 360 provides

high quality, full environment view.

KeyMission does not allow for streaming.


Proposed Solution


Proposed Solution

Software Design - Autonomous System

Raspberry Pi utilized for image processing

and manual control of camera

positioning.

Pi camera used for the purpose of

capturing video footage.

Made use of the OpenCV library that is

aimed at real-time computer vision.

Allowed for analyzing the captured

video frame by frame.

Made use of the WiringPi Python library.

Utilized to manage and alter the

PWM clock frequency of the

Raspberry Pi.


Proposed Solution


Each frame is converted to

monochrome and then

blurred.

The magnitudes of the darkest

and brightest pixels within the

frame are identified.

A light intensity value is

determined for each frame

using binary thresholding.

A Python dictionary is used to

store light intensity/brightness

values and their

corresponding positions.


Proposed Solution


A thresholded image is generated using the

blurred image and the previously outlined

brightest pixel value.

The Canny edge detection algorithm is

applied to the thresholded image.

Light contours identified

Each contour is a NumPy array of (x,y)

coordinates associated with the

boundary points of the object.

Contours sorted based on the radius of

a minimum enclosing circle around

the identified brightest object.

The position of the brightest object is

outlined in terms of pixels.


Proposed Solution


Each video frame is set up to be 400 by

300 pixels.

Pixel deviation of the brightest object

from the center of the frame in

terms of the x axis is converted to a

degree value.

Horizontal field of view

associated with the

Raspberry Pi camera is

53.5°.

The deviation value in degrees is then

converted to a step count.

Stepper motor makes 513 steps

per revolution.


Proposed Solution


Pixel deviation of the brightest object

from the center of the frame in

terms of the y axis is converted to

a degree value.

Vertical field of view associated

with the Raspberry Pi

camera is 41.4°.

The deviation value in degrees is

then converted to a PWM signal

required to move the servo motor

to the required position.

Servo motor has 180 degrees

of motion.


Proposed Solution

Software Design - Manual System (Stepper motor control)

Each stroke of the left or right arrow

key is mapped to 25 steps of the

stepper motor.

Current position of stepper is

updated and stored with

every change in position.

If the next required position of

the motor exceeds 180

degrees the stepper spins

back on itself moving to the

required position from the

opposite side.

Prevents damage of

cables during flight.


Proposed Solution

Software Design - Manual System (Servo motor control)

Each stroke of the up or down arrow key

is mapped to 10 degrees of

movement for the servo motor.

Current position of servo is

updated and stored with every

change in position.

Subdivided the Raspberry Pi

PWM clock which has a base

frequency of 19.2 MHz.

Provided a stable means of

setting up pulse width

modulation at 50 Hz.


Coil A1 = Pin 31

Coil A2 = Pin 33

Coil B1 = Pin 35

Coil B2 = Pin 37

Driver board is attached vio GPIO pins

Proposed Solution

Hardware Design


● Coil activated in series

● 513 steps/rev

● Activation of coils determines the direction

Proposed Solution

Hardware Design

Clockwise Step # Winding A Winding B Winding C Winding D Counter-

Clockwise

1 1 0 0 1

2 1 1 0 0

3 0 1 1 0

4 0 0 1 1


GPIO pin 18 is used for the purpose of

generating the pulse width modulation

necessary to control the positioning of

the servo motor.

Proposed Solution

Hardware Design


Proposed Solution

Hardware Design

PWM signals with pulse widths of

0.53 ms and 2.13 ms at a frequency

of 50Hz are used to drive the servo

motor to the extreme left and right

positions respectively.

PWM signal with a pulse width of

1.33 ms at a frequency of 50Hz is

used to drive the servo motor to

the center position.

A 0.0088 ms change in the

pulse width of the PWM signal

corresponds to 1 degree of

servo movement.


● 2 DOF system to aim camera

● Mitigate and minimize external rotational

forces

○ Cylindrical package design

○ Drag damping moment arms

○ Multiple support lines limit twist

● Decouple video payload from balloon

○ Load-rated ball-bearing swivel

● Eliminate internal rotational effects

○ Eliminate induced torque of main

scanning motor using counterweight

Proposed Solution

Mechanical Targeting and Stabilization System


● Coaxial contra-rotation

○ Gearbox uses motor input to

simultaneously rotate camera and

counterweight in opposite directions

● Design counteracts induced torque and

maintains payload balance due to its

physical symmetry.

Proposed Solution

Mechanical Stabilization System


● Layered Payload

○ .75” polystyrene insulation protects

payload components

○ Acrylic plates provide hardpoints for

component installation and rigging

● Extensive use of nylon hardware keeps

weight low

● Cast acrylic dome allows for clear view of

sky

● Total video payload weight: 5.06 lb

Proposed Solution

Video Payload Design


● Determine ballast weight required for 5 m/s

ascent rate

● Wpayload + Wballoon = Wnet (14.41 lb)

● Wgross = 1.28 x Wnet (18.44 lb)

● Wneck = Wgross - Wballoon (14.03 lb)

● Wballast = Wgross - Wfill valve = (13.5 lb)

● Set ballast weight using fish scale, then

attach ballast to balloon until the balloon

just lifts the ballast

● Cleared for liftoff!

Balloon Fill Requirements


● 1500 ft/min maximum allowable descent

rate

● 1.5 NASA safety factor for unmanned

descent

● Drag coefficient is 1.75 for dome-shaped

chute

● At terminal velocity, drag force equals

gravitational force

Parachute Sizing


Flight String Schematic


Testing Methods and Results


Testing Methods and Results - Autonomous Tracking System


http://www.youtube.com/watch?v=kl-7yY5tdqU

http://www.youtube.com/watch?v=kl-7yY5tdqU


Testing Methods and Results - Test Launch


Testing Methods and Results - Test Launch Continued

Flight Path Prediction Test Launch Flight Path


Testing Methods and Results - Test Launch Continued


Testing Methods and Results - Improvements for the future

● Damage Report

○ Top acrylic plate

○ Three foam rings

○ 3D-printed camera mount

● Assessment

○ All damaged items resulted from

payload recovery. Approximately 15

foot free fall from tree to ground.

● Solution

○ Just have someone catch the thing.



● Release of objects in flight string can be

done smoother to dampen pendular motion

during ascent.

● Had connection issues with the video

payload.

○ Were able to connect to the payload

from the Ground Station laptop over

SSH once the Ubiquiti modem on the

Ground Station had four bars.

■ Likely due to issues with the

Ground Station using the Iridium

system to automatically point

the dish towards the location of

the balloon.



● The video of the flight onboard the

Raspberry Pi got interrupted when the

balloon popped.

○ Once the successful test of the

manual control of the Pi camera was

completed the camera was left

pointing up at the balloon.

○ In the video it is possible to see the

balloon expanding.

○ Thus, once the balloon popped it

must of hit the video payload thereby

bringing the video capturing to an

end.



● Cutdown System failed to trigger cutdown

event with remote email packet.

○ Timer was set and activated when

desired, however the blade became

stuck on the plastic casing due to a

slight offset when the blade was

screwed to the DC motor

● Balloon ascended until burst around 96000 ft


Future Usage

Eclipse in April 8, 2024

Documentation and implementation for future

Temple ballooning teams

Construction of ground station for senior design

team starting in Fall 2017

Possible addition of higher quality camera


Reliable means of video capture

Sensor and Tracking data from full

launch



project success

Minimum video capture of 20 mins

Deliverables

Ability to manually and

autonomously track eclipse/sun

Full GPS tracking data, reported at

30 second intervals.



project success

30+ mins of test data collected


Thanks for Listening!

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