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The Air Jellyfish

Group #1: Jacob ChardBen Sponagle Chris TheriaultShane Yates

Supervisor: Dr. Marek Kujath

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Introduction◦ Inspiration◦ Objectives◦ Fall Term Testing and Calculations

The Design◦ Alterations◦ Fabrication

Budget Testing and Evaluation Conclusions and Recommendations

Outline

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The Inspiration: Festo AirJelly

Remote-controlled airborne jellyfish

Central electric drive moves tentacles

Horizontal motion controlled by centre-of-mass-shifting pendulum

Source: www.festo.com

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Mimic appearance of a jellyfish

Achieve flight

Create effective advertising medium

Objectives

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Fall Term Testing Mock up Model

◦ Double Pulley Mechanism vs. Pulley/Spring Mechanism

◦ Flexible Legs vs. Hinged Paddles◦ Oscillation Frequency

Calculations◦ Torque Requirement◦ Drag Forces◦ Lift

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Calculations: Drag Forces

0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 2.50

0.20.40.60.8

11.21.41.61.8

Drag Force vs. Diameter at Different Velocities

V = 0.25 m/s V = 0.5 m/sV = 0.75 m/s V = 1.0 m/s

Diameter (m)

Dra

g Fo

rce

(N)

Drag Forces were found to be small

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Torque Requirement

0 10 20 30 40 50 60 70 80

-6

-4

-2

0

2

4

6

8

10

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Total Force vs. Position

Angular Position (deg)

Tota

l For

ce (

N)

Calculated to be 5.82 Nm

Motor selected based on torque requirement

HG312 Geared Motor 312:1www.robotmarketplace.com

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Lift

0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 2.50

1

2

3

4

5

6

7

8

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Generated Lift vs. Balloon Diameter

Balloon Diameter (m)

Gen

erat

ed L

ift (

kg)

2.1m diameter balloon produces 5kg Lift

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Frame Vertical Propulsion Mechanism Balloon Motor/Crank Steering Mechanism Wireless Control Circuitry

The Design

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The FrameCarbon

Fibre Tubes

Rapid-Prototyped Joints

Rapid-Prototyped Hinges

Rapid-Prototyped Motor Platform

Aluminum Tubes

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Vertical Propulsion Mechanism•Flexible flappers

-Vinyl Beams-Foam Board Paddles

•Upward thrust throughout stroke

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Transmission

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Weather Balloon

Helium Used for Lift

Net/Ring Support

Balloon

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Dual Propellers

Provide linear horizontal movement and turning capability

Steering Mechanism

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FM transmitter and receiver

Servo motors activate on/off switches

Dedicated power supply

Wireless Control

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Lithium-Polymer battery pack◦ 3 cells (3.7 V each)◦ 2600 mAh capacity

Provide ample power for >30 min of operation

Primary Power Supply

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AlterationsItem Initial Design Final DesignBalloon attachment

Nylon straps Cargo net over balloon; circular nylon strap around base of balloon

Advertisements TBD Pasted to paddles; banner attached to net

Flappers Two alternatives Flexible legs and rigid paddles

Motor 24 V DC 12 V DCTransmission Slider-rail “Scotch

yoke”Crank with guide-holes for cables

Control Electronic speed controllers

On/off switches flipped by servos

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Joints, hinges, and base of motor platform were rapid-prototyped

Frame assembled with press-fitting Motor hub machined by Albert Motor stand made of balsa; attached to

base with epoxy Sewn balloon attachment ring

Fabrication

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Item CostHelium $440Rapid prototyping $440Batteries and charger $400Pulleys $130Balloons $80Frame rods $70Primary motor $60Flappers $30Miscellaneous (fasteners, electrical parts, etc.) $120Total $1770

Budget

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Three tests conducted in Sexton Gym

Number of tests limited by cost of helium (~$100 to fill balloon)

Testing

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Insufficient helium to achieve flight

Verified all mechanical systems◦ Propellers moved device forward and provided

turning capability◦ Crank mechanism drove flappers with appropriate

range of motion

Learned lessons concerning device assembly

Test 1: March 27

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Achieved controllable flight◦ Operated for over 30 minutes◦ Reached height of 8 m◦ Controlled from 28 m distance

Lessons learned◦ Difficult to determine orientation of device from

distance◦ Helium leakage might limit run time

Test 2: April 1 (It flew!)

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Test 2: April 1 (It flew!)

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Test 2: April 1 (It flew!)

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Added advertisements and orientation indicators

Balloon ruptured during assembly

Test 3: April 6

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Design RequirementsRequirement Fulfilled

Fit in a cube with 3m sides

Generate vertical propulsion with flapping appendages

Rise to a height of 8m

Operate for a period of 30 minutes

Be maneuverable in three dimensions

Weigh less than 5 kgBe operational for a period of at least one day without maintenance

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Design RequirementsRequirement FulfilledBe safe to use. The building and testing of the prototype must also adhere to all safety procedures in accordance with Dalhousie University.

*

Be operational at a distance of 20 metres away from the operator.Have an attached advertisement that is interchangeable (i.e. the advertisement can be removed and replaced with a different advertisement).Function in an indoor and outdoor environment *

Be aesthetically pleasing as it is to be used as an advertising medium to draw attentionBe built under a budget of $2000.00.Be completed in conjunction with the deadlines set by the MECH 4010 syllabus.

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Positives Overall success Most requirements met

Negatives Reliability issues

◦ Fragility of balloon Time and effort for assembly Cost of helium

Conclusions

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Balloon reliability enhancement◦ Use a more rigid balloon◦ Contain balloon in protective envelope

More advanced control system◦ Height and obstacle detection◦ Motor speed controllers

Organic steering mechanism

Recommendations

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Sponsors Shell Canada Welaptega Marine Air Liquide

Individuals Dr. Marek Kujath Albert et al. Dr. Julio Militzer Peter Jones Craig Arthur

Acknowledgements

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Questions?