mechanical engineering 8936 term 8 design project february 3, 2012

Design Review #1Autonomous Hovercraft

Mechanical Engineering 8936Term 8 Design Project

February 3, 2012

AgendaProject ScopeBackgroundSimulationDesign ConsiderationsHardwareSoftwareProject ManagementFuture ConsiderationsConclusion

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Project Scope The scope of this project is to complete

research that will lead to the design and construction of an autonomous hovercraft. The hovercraft will have the ability to maneuver a path that will contain multiple obstacles. This hovercraft can then be used to find an object or give video surveillance and return to its initial launch point.

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Background of HovercraftA hovercraft is a vehicle that floats or hovers

on a cushion of pressurized air.A hovercraft consists of:HullSkirtLift FanPropulsion Fan

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Design Parametersα = Hovercraft Angle Headingβ = Hovercraft Angle of VelocityE = Drive ForceF = Friction ForceT = Yaw TorqueM = Mass I = Yaw InertiaK = Dart Effect J = Yaw DragX = Prop Coefficient Relating Ramp up SpeedY = Prop Coefficient Relating Maximum TorqueZ = Coefficient of Friction

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Governing Equations

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Equations of Motion Drive Equation

Yaw Control

Translation Control

SimulationEffects of

Variables on Hovercraft Control

Root Locus & Simulink

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Simulation

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Variable Effect Design Considerations

Mass: MFaster response more damping for smaller

valuesLightweight

Moment of Inertia: I

Faster response for smaller values, damping

effect negligible

Mass located to reduce moment of inertia

Yaw Damping: J

Response speed decreases with increasing

values. Damping only signification for J = 0.

Low yaw damping desirable

Dart Effect: K

Unstable for negative values, slower response

for increasing values, negligible damping

Balance mass as well as possible, front heavy is unstable, back heavy is

stable but reduces response time

Prop Torque: Y

Poor damping at low values, negligible

response speed until a critical value where

response speed decreases

Ensure sufficient torque available for fast

response, control system design to compensate for

poorer damping

Friction: Z Faster response, more damping at higher values High friction desirable

Simulation

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Design Consideration

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Motor SelectionPropulsion Motors

Voltage (V) Motor 1 Thrust (g) Motor 2 Thrust (g)

3 5 7

6 8 10

9 15 18

12 32 33

Lift Fan Motors

Temperature (oC)

Motor 1 104

Motor 2 83

Motor 3 61

Design ConsiderationFoam Skirt

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Foam Skirt

Weight (g) 16.474

Relative coefficient of friction High

Young's Modulus 10^9 N/m2, GPa

3.5

Design ConsiderationFabric Skirt

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Fabric Skirt

Weight (g) 9.290

Relative coefficient of friction Low

Young's Modulus 10^9 N/m2, GPa

N/A

Design ConsiderationRubber Skirt

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Rubber Skirt

Weight (g) 34.292

Relative coefficient of friction

Medium - High

Young's Modulus 10^9 N/m2, GPa

0.1

Hardware16F876 PIC2200 mAh LiPo Battery (11.1 Volts) to run H Bridges9 Volt Battery to run PIC

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HardwareSharp GP2Y0A02YK0F IR Range Sensor - 20

cm to 150 cmMaxbotix LV-MaxSonar-EZ0 High

Performance Sonar ModuleDual Axis Gyro Breakout Board IXZ500

±500° / secHMC6352 Compass Module

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SoftwareProgramming in C, Converted to HexCode Will Interpret Sensors to Navigate PathPID Control Algorithm for Cornering

Potential Issues With Errors in Calculations, Sampling Time

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Project ManagementProject ScheduleProject BudgetWebsite

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Project Schedule

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Project Budget

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Starting Budget

Faculty of Engineering $250.00 Group Members $50.00

Total: $300.00

Costs to date

Sonar Range Finder $26.89 Gyroscope $41.19

Digital Compass $37.11 HST/ S&H $24.12

Remaining Funds $170.69

Project Website

www.autonomoushovercraft.yolasite.com

Please Visit!

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Way ForwardMore robust prototypeVideo surveillance Determine system parameters for simulationIntegration of PIC board with sensorsDesigning lift fanPurchase new hardware

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Conclusion

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Project ScopeBackgroundSimulationDesign ConsiderationsHardwareSoftwareProject ManagementFuture Considerations

Thank You!Any Question?

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