AGGIELOOPFinal Design Presentation

Presented by:Tadeo Huerta, Craig Medlin, Morgan O’Neil, Tyler Paschal, and Nathan Stephens

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IntroductionNeeds Statement

“Provide a design for a reusable capsule that will safely, reliably, and comfortably transport up to 30 passengers through a low pressure tube up to – and down from – high speeds with minimal losses due to drag and friction. This

system will provide maximum passenger throughput with minimal downtime between departures.”

About Our Pod• Aggieloop-001 “Basilisk”

• Semi-monocoque aluminum construction with a carbon fiber outer skin

• Air bearing levitation system

• Transports payloads at relatively high speeds efficiently and safely

What makes us unique?• Proven Industry Components

• Battery Cooling System

• Flexible Design

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Aerodynamics & StructuresShell

• CFRP

• Profile optimized using CFD

• Structural support, aerodynamic efficiency, and light weight

Structure• 6061-T6 Aluminum

• Semi-monocoque construction

• MATLAB optimization

• Structural support of a solid body, light weight, conforms to shell

Ducting• Sheet steel

• Housing for fan/compressor at full scale

• Reduces air pressure at nose

• Added diffuser for increase in fan/compressor performance

CFRP Shell

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Aerodynamics & Structures

6061-T6 Aluminum Semi-monocoque (Preliminary)

Shell• CFRP

• Profile optimized using CFD

• Structural support, aerodynamicefficiency, and light weight

Structure• 6061-T6 Aluminum

• Semi-monocoque construction

• MATLAB optimization

• Structural support of a solid body, light weight, conforms to shell

Ducting• Sheet steel

• Housing for fan/compressor at full scale

• Reduces air pressure at nose

• Added diffuser for increase in fan/compressor performance 4

Aerodynamics & Structures

Air Bypass Ducting

Shell• CFRP

• Profile optimized using CFD

• Structural support, aerodynamic efficiency, and light weight

Structure• 6061-T6 Aluminum

• Semi-monocoque construction

• MATLAB optimization

• Structural support of a solid body, light weight, conforms to shell

Ducting• Sheet steel

• Housing for fan/compressor at full scale

• Reduces air pressure at nose

• Added diffuser for increase in fan/compressor performance5

• Acceleration– Pod pusher for acceleration to test

speeds

• Air Bearings– Near Frictionless interface with

tube

– No need for thrust

– Allows for longest time at test

speed without providing thrust

Levitation

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Pusher Interface and Compressed Air Tanks

• Acceleration– Pod pusher for acceleration to test

speeds

• Air Bearings– Near Frictionless interface with

tube

– No need for thrust

– Allows for longest time at test

speed without providing thrust

Levitation

Isometric view of Sled

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Levitation

AIRFLOAT Air Skids:• Optimized for smooth surfaces

• Varied and frequent use in industry

• Low air tank capacity and airflow

requirement

• Utilizes pressurized air

• Vertical self-regulation

12” Air skids (AIRFLOAT)

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Horizontal Stability wheels• Guides the pod along the rail

• Keeps in constant contact with the rail

• Is dampened to avoid other parts of pod coming

into contact with the rail

• Springs only exert minimal pressure on the rail

Stability

Front view of wheels on rail

Isometric view of wheels on rail

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High capacity wheels• Solid

• Deployable

• Powered by a 5 HP AC Motor

Disc Brakes• Adjustable brakes for constant braking

• High friction on concrete on the outside of the

aluminum track

Taxiing and Braking

Notional Wheel and Brake design

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Axle Brakes• Backup for Disk Brakes

Deployment• Spring and diaphragm pneumatic actuators

that raise when filled with air

• Use of two solenoids to fill and dump

diaphragm provides redundancy

Controls

• Control Unit

– Single Board Computer

– Embedded Linux

• CAN Bus

– Reliable– Industry Proven

• “End Node” Module provides universal interface

• SpaceX Network

– Telemetry

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“End Node” Board Designed by Aggieloop

Controls• Safe-Stop

– In case of any of the following:

• Tube anomaly

• Excessive vibration

• Excessive acceleration

• Loss of air bearing pressure

• Operator input– Stop command will be issued

• Deploy wheels, apply brakes at full power

• If brakes fail, engage emergency brake

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Conceptual GUI Mockup

Sensor Locations

13Potential Exterior Sensor Locations

Sensor Locations

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Notional Battery Temperature Sensor Location

Sensor Locations

15Prototypical Internal Sensor Locations

Energy

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Li-Po Battery Selection• High energy density• Ease of overall maintenance• Fewer cells than Lithium-Ion• Hard-case pack filled with

fire-safe material

EnergyHigh Voltage Module• Main source of power• 4 modules on boardModule Specifications

● 60 VDC● 285 Ah● 2.5 kWh● 55 cells

Pack Integration● Four modules wired in series● Provides enough power to run all

components through testing procedures, and during the actual run

● Refrigeration system to operate in vacuum pressure to cool batteries

Module of 55 batteries

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Energy

12 V Battery

12V Module

Specifications● 12 VDC● 15 Ah● 180 kWh

Pack Integration• Redundant power supply for the control systems• Location isolated from the main battery bank• Enough power to activate the pod stop command

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Cooling

Purpose• Provides cooling for high energy batteries• Operates in vacuum pressures• Utilizes air from air bearings for cooling medium

Plate Heat Exchanger• Efficient cooling in low volume device• Thin plates optimize surface area• Multiple plates maximizes volume flow

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Plate Heat Exchanger

Cabin

Payload• Simulated weight of 8 people and life support systems for small scale

• Can simulate this weight with experimental equipment– Have the capability of running pod with pressurized, or low pressure

equipment on board

Life Support• Air conditioning, CO2 scrubber, backup air supply• Backup lights

– Battery powered, and glow strips for redundancy

• Added door for access to cabin to place sensors, ballast, and experimental equipment

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Cabin

Cabin External RenderingCabin Cross Section

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Conclusion

Aggieloop-001 "Basilisk"– Cost: $40,000– Length: 16’– Weight: 2500 pounds– Structurally sound– Flexible design– Aerodynamically efficient– Sufficient power supply– On-board experimentation

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Why We Are Here• To pursue our passion• Make a contribution• Change the world

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Special Thanks

Flow Optimization

Solidworks CFD simulations – Simulated pod in tube, with air flowing around– Low drag at 0.02 psi in tube (~1.5 lb)– Internal (ducting) and external simulations

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External Flow Simulation Internal Flow Simulation

MATLAB Optimization

Method

• Dependent variables: Stresses on structure

• Independent Variables: Member cross sectional area; Components in pod

• Control Variables: Quantity of structural members

• Grid based optimization of all combinations of members

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Approach

• Utilizes solid mechanics principles for structural analysis

• Purpose: Optimize quantity of structural members used in semi-monocoque

Levitation

Air Bearing Cross Sectional View Diagram26

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Levitation Comparison

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Air Bearings (Air Float)

Magnetic Levitation (Arx-Pax)

Lift Capacity (per pair) 6,000 lb 243 lb

Cost (per pair) $2,250 $10,000

Power Consumption (W)

Minimal (Power draw from regulators)

4400

Number of Pairs 2 11

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Secondary Movement • Suspension

– Inspired by motorsport• Pushrod actuated suspension mounted on linear

actuators• Motor for taxiing

– 5hp AC motor• Cheaper than equivalent DC motor• Lighter than equivalent DC motor

– Connected to wheels via CV axles

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Wheels

• Pistons use air pressure to raise the wheels–In case of pressure loss wheels will automatically deploy with

assistance from springs

• Wheels will be retracted once the air bearings take the load of the pod• There will be a pair of solenoids on each line to the pistons

–Controls the airflow to the pistons, allows for fault tolerance• Once the wheels are deployed the brakes will engage

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Controls

30Controller System Network Flow Chart

Sensors

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• High tech laser-retroreflective sensor

• Contains laser of class 2• 30 micro-second response time • Sensing range is 10 meters• Retro-reflectivity will keep track

of the pod’s position• Remaining pod length can be

calculated • Location is top front of the pod

DK_LAS-54/76/110/124 Contrast Sensor GP2Y0E02A Orientation Sensor• Measures distance using a

CMOS image sensor and IR-LED

• Depending on detected distance it will output a corresponding voltage

• Location will be along side each exterior corner of the pod

• All four sensor’s data must be equal to ensure correct orientation else breaks will be deployed

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Sensors

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BMA280 Accelerators • 2mm X 2mm• Triaxial• Low-g acceleration sensor • Contains digital interfaces• Ability to sense tilt, motion,

and shock• Location on bottom of

passenger compartment

BME280 Pressure/Temperature/Humidity  • High linearity• High accuracy• Long term stability• Absolute barometric

pressure sensor- exceptionally high accuracy

• Measures ambient temperature at very low noise and high resolution

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Sensors

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ADXRS453 Attitude Sensor • Complete rate gyroscope• 300 degree per second angular rate

sensing• Ultrahigh vibration rejection• Internal temperature compensation• SPI Digital output with 16-bit data

word • Consistently checks for angular

rotation of the pod• If out of range motion detected the

wheels will be deployed

LDT0-028K Vibration Sensor • Contains Polymer film • Screen-printed electrodes • Two crimped contracts• High voltage generated if film is

displaced from neutral axis• Vital component of pod’s

stability detection • Reports stable/unstable state• Location includes forward and

backward interior of the pod

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Energy

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Power Consumption vs Battery Capacity

Energy

Wiring Schematic

High Voltage Pack

Specifications● 240 VDC● 285 Ah● 10 kWh● 220 cells

Battery Control Module● Balances charging/discharging of cells

Electrical Distribution System● Transmits energy to Pod components

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Cabin Figures

• Seat Pitch– 48 in

• Seat Width– 22 in

• Ceiling Height– 66 in

• Estimated Full Scale Mass– Carry on per person – 18 lbs– Seats – 15 lbs each– People 120 lbs (5th percentile) – 220 lbs (95th percentile)– Estimated mass of life support systems – 750 lbs– Small scale estimated total mass – 870 lbs

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• Cabin Pressure - 11.34 pisa

• Cabin Temp - 72 F

• Cabin Humidity Level - 0.12%

• Partial pressure CO2 after journey - 0.11 psia

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Full Scale Cabin Safety

• Fire– 3m Novec 1230 fire protection fluid

• Nontoxic to the environment• Faster than CO2

• Air– Emergency Air Required

• 10.57 lbs (21 % O2, 79% N2/H)• Stored in composite pressure vessels

– Loss of Cabin pressure• 10.17 psi (Stable Cabin pressure: 11.4 psi)• Drop down masks

– High CO2 content• Flood Style air replacement

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• Emergency Door Opening Procedure– Analog Gauge Displays pressure difference

between the cabin and the tube• In case of total power loss• Easily readable

– Mechanical system only allows door to open when there is a safe pressure differential

• Emergency Lighting– Battery powered in case of total power loss– Afterglow phosphor based material

• 30 hours of luminescence• Incase battery lights are out

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Full Scale Safety

• Total power loss– Backup battery ensures the on board computer can still bring the pod to a controlled stop.

• Atmosphere introduction in tube– Pod will naturally begin to slow down due to higher air pressure. T– he on board computer will then bring the pod to a controlled stop

• Pod becomes stuck in tube– Reintroduce atmosphere to the tube, enter the tube– Determine if pod can be moved out of tube under its own power

– Remove pod from tube• Redundant systems

– Redundant power supply– Redundant systems for deploying the wheels– Redundant life support systems– Redundant systems for slowing down the pod

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