Design and Build of Design and Build of anan

Autonomous Robotic Autonomous Robotic ParagliderParaglider

Level IV Design Project 2006Level IV Design Project 2006Project 415Project 415

Stephen Craig, Ben GransdenStephen Craig, Ben Gransden

Dr. Damien LDr. Damien Leclercq, Dr. Frank Wornleeclercq, Dr. Frank Wornle

Autonomous RoboticAutonomous RoboticParaglider ProjectParaglider Project

Project GoalsProject Goals Demonstrate the paraglider flying Demonstrate the paraglider flying

autonomously in a circle of one hundred autonomously in a circle of one hundred metre diametermetre diameter

Provide capability to send commands to Provide capability to send commands to the paraglider whilst operationalthe paraglider whilst operational

This seminar will coverThis seminar will cover Brief backgroundBrief background Several aspects of the design of the Several aspects of the design of the

systemsystem Testing and validation of project outcomesTesting and validation of project outcomes

ServoServo

Parafoil

MiniDragon

PressureSensor

GPS2.4 GHz

Transceiver

BackupReceiver

VoltageRegulators

Gondola

LaptopDragon12

2.4GHzTransceiver

11.1V LiPo Battery

11.1V LiPo BatteryESC Motor

11.1V LiPo Battery

SourceSelect

BackupTransmitter

System SchematicSystem Schematic

Parafoil TheoryParafoil Theory

Parafoil TheoryParafoil Theory

Similar principle to Similar principle to an airfoilan airfoil

Inflated wingInflated wing Stagnation pointStagnation point

Keeps wing inflated Keeps wing inflated or close to rigidor close to rigid

(ADVENTURE Paragliding and Kiteboarding, 2004)

Paraglider TheoryParaglider Theory

Brake steeringBrake steering Increases drag on Increases drag on

one side of parafoilone side of parafoil Weight shiftingWeight shifting

Modifies angle of Modifies angle of attack of side of attack of side of parafoilparafoil

Rear View Top View

Projected flight path

Projected flight path

Weight Shifting Steering Method

Parafoil DesignParafoil Design

Wing loading vs Wing loading vs AirspeedAirspeed

GivenGiven W = 20 NW = 20 N V = 6 m/sV = 6 m/s

RequiredRequired S = 1.46 mS = 1.46 m22

Prototype ParafoilPrototype Parafoil Parafoil purchasedParafoil purchased

S = 1.64 mS = 1.64 m22

238.0 VS

W

For CL ≈ 0.3

(Tennekes, 1997)

Gondola DesignGondola Design

Lift/Drag RatioLift/Drag RatioRequired Thrust Required Thrust

6.6N6.6N

Propeller diameterPropeller diameter

Calculation of Calculation of motor powermotor power

3

123

2

0 )2

1( DPT i

(McCormick, 1995)

Gondola DesignGondola Design

Steering Steering mechanismmechanism

Lightweight Lightweight materialsmaterials

Low air resistance Low air resistance for propellerfor propeller

Communications

Communications

2.4GHz Transceiver Modules Unreliable Radio Link

Signal Attenuation Interference Noise

error prone linkabcdef… abc¿af.. Paraglider

Crash!

Communications Solution: Reliable Transmission Protocol Error Detection

16-bit CRC

Paraglider

error prone linkabcdef…xyz CRC

abc¿af…xyz CRC

CRC CRC!=

Discard Data…

Transmission Error Detected

Communications

How does the laptop know whether the paraglider has received the message?

Solution: Packet Identifiers and Timeouts

123+N CRCerror prone link Paraglider

error prone linkabcdef…xyz CRC

CRC

123

abcdef…xyz123

CRC123+N

Success!Acknowledged

Paraglider

Timeout

Communications

Paraglider

Retransmit

150 N=20

170

170 N=25

195

170 N=25

195

DuplicateDetected

Communications

Other Issues: Scheduling Behaviour on Reset

Result: Reliable Link

Paraglider

abcdef… abcdef…reliable link

reliable linkzyxwv… zyxwv…

Kalman FilterKalman Filter

Kalman FilterKalman Filter

GPS data inaccurateGPS data inaccurate 5 metres horizontal5 metres horizontal 10 metres altitude10 metres altitude

Optimal observerOptimal observer Uses knowledge of Uses knowledge of

noisenoise Prediction/Prediction/

CorrectionCorrection Pressure sensorPressure sensor Fuzzy ControllerFuzzy Controller

(Welch and Bishop, 2006)

Testing – CurrentTesting – Current

Motor mount Motor mount failurefailure

Line hook upsLine hook ups New design New design

currently being currently being builtbuilt More rigidity More rigidity Hook points Hook points

coveredcovered

Testing – CurrentTesting – Current

Radio testing Radio testing 80 metres outdoors80 metres outdoors 50% packet loss50% packet loss

Testing - FutureTesting - Future

Further testing of Radio and JavaFurther testing of Radio and Java Four major stages of testingFour major stages of testing

Non-flight mode – WheeledNon-flight mode – Wheeled Flight mode – Manual (no GPS)Flight mode – Manual (no GPS) Flight mode – Manual (with GPS) Flight mode – Manual (with GPS) Flight mode – AutonomousFlight mode – Autonomous

DemonstrationDemonstration

Run DemonstrationRun Demonstration

Questions?Questions?