PowerPoint Presentation

Team #2 Solar Car ProjectProject Proposal

Team MemberMechanical EngineersElectrical EngineersKeith DalickEmiliano PantnerAdrian CiresShishir RajbhandariJames BargeZachary PrislandNovember 2010BodyNovember 2010BodyDeciding factors for the body designLight weightAerodynamicSix square meters of Solar Array spaceSize requirements for raceHigh strength

November 2010Proposed DesignMonocoque ConstructionConstruction technique that utilizes the exterior of the body as the load bearing

November 2010Proposed Design Designed using SolidWorksAerodynamicFlow analysis using CAD modelCarbon Fiber Light weightVery strongShaped using wood moldsHigh cost

November 2010Proposed Design

November 2010SteeringNovember 2010Proposed DesignRack and Pinion Steering SystemConverts the rotational motion of the steering wheel into the linear motion needed to turn the wheels. It provides a gear reduction, making it easier to turn the wheels.

November 2010Statement of WorkWork with engineers designing body, and suspension of front two wheels.

Steering system will be designed in respect to bodys dimension and design.

Analysis of key components:

Rack and Tie Rod dimensions

Ackerman angle for steering, steering bar location, Kingpin axis, Steering Knuckle location

Steering Stops

Geometry and dimensions of the system.

November 2010Statement of WorkDetermine steering ratio

Analyze design using SolidWorks and working model to test linkage

Order parts needed for assembling the system

Verify steering system can complete all required tests in order to compete in race

November 2010Braking SystemNovember 2010Proposed designTwo disc brake systems on front two wheels

Manual parking brake

November 2010Statement of WorkBraking forces for each front tire will be calculated using an estimated total vehicle weight

Analysis and sizing of components Pedals Master cylindersBrake calipers Disc

November 2010Statement of WorkRace regulationsBrake pad must have a contact area with the brake disc greater than 6.0 cm^2.Solar cars must be able to repeatedly stop from speeds of 50 km/h or greater, with an average deceleration, on level wetted pavement, exceeding 4.72 m/s^2.November 2010SuspensionNovember 2010SuspensionThe job of a car suspensionMaximize the friction between thetiresand the road surfaceProvide steering stability with good handling Ensure the comfort of the passengersApproachWork with the engineers designing the body, braking and steering systems, and motorNovember 2010Independent SuspensionIsolates vehicle by its points of contact from the roadEliminates disadvantages of beam axleLoss of friction by the wheelsSmall maximum spring deflectionNo steering system controlOver-steerNovember 2010Front SuspensionObjectiveDesign a double wishbone suspension for the front wheelsChoose the right shock sizeShock size will depend on total weight of the car

November 2010Double Wishbone2 wishbone shaped linksProvide a strong member to overcome forces from braking and accelerationFixed to the frame and upper and lower ball jointsSpring and damper between the 2 wishbones

November 2010Double Wishbone AdvantagesKinematics easily tuned and optimizedMore control over camber angle (degree to which the wheels tilt in and out)Minimize body roll and swayMore consistent steering feel

November 2010Roll and Camber AngleBody RollCamber Angle

November 2010Rear SuspensionObjectiveDesign a trailing-arm suspension for the rear wheelChoose the right shock sizeShock size will depend on total weight of the carMotor will be mounted on rear wheel

November 2010Trailing Arm Arm joined at the front to the chassisAllows the rear to swing up and downNo side-to-side scrubbingOnly allows the wheel to move up and down

November 2010Suspension DesignSystem will be designed in SolidWorksCustom parts includeTrailing armWishbone arm linksHubKnuckleFork-shaped linkShocks will be bought according to calculated specificationsNovember 2010Suspension TestingIndividual then as a wholeStructural testing in SolidWorksFinite Element AnalysisFatigue and stress pointsMSC Adams/Car to analyze and predict Roll and vertical forcesStatic loadsSteering characteristicsWheel travel Adjust camber angle, caster angle, toe pattern, roll center height, scrub radius, and scuff Smoother and more comfortable ride

November 2010CAD Testing ExamplesPositioningFinite Element Analysis

November 2010Power GenerationNovember 2010Power Generation

November 2010Cell, Module, Array

November 2010Solar PowerPerformance:InsolationSemiconductor (Si, GaAs)TemperaturePosition of sunWeather

November 2010Solar CellSingle Junction SiliconAmorphous Multi-junction SiliconCheapEfficiency = 14 -16 % Fill Factor > 0.4 Voc, Isc Not-FlexibleEasily BrokenNot Waterproof

ExpensiveEfficiency = 10-12 % Fill Factor = 0.67-0.75 Voc, IscFlexibleDurableWaterproof

November 2010Solar Module32 - 36 Cells (series) / moduleEncapsulate Electrical parameters (Isc Voc)Mismatch effectBypass diode2 Bypass diodes/ 36-cell module

November 2010Bypass Diode, Blocking Diode

November 2010Solar ArraySeries/Parallel module = Solar array1 Blocking diode per moduleMinimize cell temperaturePV Array Voltage > Battery VoltageMax array power = 750 W

November 2010MPPTMaximum Peak Power TrackerDC:DC Converter 92-97% efficiencyOptimizes power output from panel while providing maximum amps into system1 MPPT per solar panelWinter, cloudy, hazyOvercharge, reverse current protection

November 2010Regenerative BrakingBrake -> Motor -> Motor controllerKinetic energy to electrical energyMotor becomes generatorCharge stored in battery60 70 % Efficiency (commercial E-V) Friction + Regenerative Braking = Total Braking Output

November 2010Control SystemNovember 2010OverviewIntegration of control subsystems

Dashboard interface for driver input

Provides driver with telemetry and car systems status information

November 2010Master Control UnitMicrocontroller BasedI/O linesSerial PortsRelays/SwitchesServo controlLCD Output

Communicates with and manages control subsystems

November 2010DashboardCurrent FeaturesSpeedometerThrottle GaugesControl Enable SwitchAir Gap AdjustmentPre-charge Switch

November 2010DashboardNew FeaturesState of Charge MeterLCD DisplayVideo DisplayLight SwitchesAutomated StartupAutomated Gap Control

November 2010Management systemNovember 2010OverviewNovember 2010Protection CircuitProtection TypeRestraining ValueOver Voltage4.25 VUnder Voltage2.5 VOver Current120 AOver Temperature75 CKeep batteries in safe operating rangeSend signal to Battery Management System (BMS)Will require use of the microcontroller

November 2010Battery Management System(BMS)Designed for electric car useFour signal inputsSlowly powers down the system

November 2010Voltage ProtectionCell Modules will be used for voltage protection:Already connected to each cellBig series signal from BMSBreak signal circuit if outside operational voltageNovember 2010Current Protection

Current TransformerWill send information to microcontrollerThis information will also be used for SOCNovember 2010Temperature ProtectionPTC ThermistorPositive temperature coefficientIdeally hooked up directly through BMSCut off temperature, drastic increase in resistance

November 2010State of Charge (SOC)The state of charge will display information for the driver about battery levelsVoltage DisplayCurrent DisplayTemperature DisplayBattery Fuel Gauge (purchased device)Will attempt to use information obtained from protection circuitryNovember 2010Power ControlCreation of a power busVoltage regulation (batteries/solar)Regenerative brakingPre-charge circuit for motor controllerElectronic relay for shutdownNovember 2010Budget & ScheduleNovember 2010BudgetBudget estimate to date: $38,168Budget from University: $5,000Deficit: $33,168DonationsHexcelSolidWorks

ItemCostCarbon Fiber Composite$ 1,800Resin$ 500Solar Cell$ 15,396Power Tracker (MPPT)$ 800Camera & Display$ 150Misc Electrical$ 500Microcontroller$ 180Aluminum Stock$ 108Suspension Parts$ 315Braking System$ 400Steering System$ 434Misc Mechanical$ 150Driver Related Equipment$ 435Competition Fees$ 7,000Travel Expenses$ 10,000Total $38,168

November 2010Major MilestonesSystem level design review November 15, 2010

Assemble lower bodyDecember 16, 2010

Assemble upper bodyJanuary 21, 2011

Detailed design review and test planJanuary 27, 2011

Configure lower bodyFebruary 21, 2011

Install solar arraysFebruary 23, 2011

Total body configurationMarch 15, 2011Final testingMarch 29, 2011

November 2010Questions???November 2010AppendixNovember 2010Over-steerNovember 2010

References2CarPros. "How to Replace Rear Brake Pads and Rotor." n.d. 2CarPros - Car Questions & Answers. 26 August 2010 .Barrys Tyre & Exhaust Centre. "Wheel Alignment." 2010. Barrys Tyre & Exhaust Centre. 29 October 2010 .CR Magnetics, Inc. CR Magnetics: Products. n.d. 29 October 2010 .Dvorak, Paul. "Auto Suspension Design Made Easy." 18 August 2005. MachineDesign.com. 27 October 2010 .EV Power, Australia Pty Ltd. EV Power: Products. n.d. 29 October 2010 .Isaac-Lowry, Jacob. "Suspension Design: Types of Suspension." 22 August 2004. Automotive Articles. 27 August 2010 .MSC Adams. "What's New: Adams 2005." 2005. MSC Software. 29 October 2010 .Nice, Karim. "How Car Steering Works." 31 May 2001. HowStuffWorks.com. 25 October 2010 .. "How Disc Brakes Work." 21 August 2000. HowStuffWorks.com. 26 October 2010 .Rapid-Racer. "Suspension." 2010. Rapid-Racer. 29 October 2010 .Robert Q. Riley Enterprises, LLC. "Automobile Ride, Handling, and Suspension Design." 2009. Robert Q. Riley Enterprises, LLC. 29 October 2010 .Spectrum Sensors and Controls, Inc. Spectrum Sensors and Controls: PTC - Engineering. n.d. 29 October 2010 .November 2010