fdr by zhangyun



                         Design Presentation
                        Project: 2007 R.E.V. Team

                                Presented By:

   Elizabeth Diaz      Jason Miner              Jared Doescher      Josh Wales
Kathy Murray        AJ Nick             Dave Wickers             Oliver Zimmerman
                           Project Scope:

• Design and Build an electric racing vehicle

• Promote community awareness of electric vehicles

•Electric Car designed to compete in SCCA Autocross
        and Formula Hybrid competition

       - Competing as “Hybrid-in-Progress” vehicle for
             one year only

       - Electric Car designed to compete in Autocross,
                Acceleration and Endurance races

•Will meet requirements for the 2007 Formula Hybrid
        competition and NEDRA race competition
                   Engineering Objectives:

• Acceleration from 0 to 60 mph in under 5 seconds

• Top speed of 80 mph

• Maximum power available between 20 and 40 mph

• Lightweight (under 650lb without driver)

• 15 minute battery life for continuous draw
                                                Team Organization:

                                                           Team Lead

                        Development Group            Procurement Group              Manufacturing Group

                                                       Integration Team

                                                          Design Teams

 Chassis & Body           Vehicle Dynamics      Driver Interface & Ergonomics    Drive System         Electrical

Chassis Redesign         Suspension System   Cockpit Design                  Motor              Battery Management
Body Redesign            Steering System     Safety Equipment                Drivetrain         Instrumentation
Mounting Points          Braking System      Driver Interface                Control System     Data Transfer System
Aeros/Ground Effects                                                           Battery System     Power Management
                                                                                Cooling System
                                                                                Shielding System
               Team Organization: REV Design Teams
                          Team Lead:
                        Elizabeth Diaz
  Design Teams

Drive System Team:   Vehicle Dynamics Team:   Chassis & Body Team:

Josh Wales           Jason Miner              Jason Miner
AJ Nick              AJ Nick                  Dave Wickers
Kathy Murray         Dave Wickers             AJ Nick
                                              Jared Doescher
                                              Kathy Murray

 Electrical Team:    Driver Interface Team:
Matt Reedy           Oliver Zimmerman
Valerie Bastien      Dave Wickers
Audrey Moyers
Kristi Harrell
                     Major Goals of the Team

• Complete the car

• Create/Integrate Lithium-Ion pack

• More publicity
  – Autocross racing
  – More EV events
  – Local advertising

• Funding
                            Florida Tech REV

• Overall Length, Width, Height:
  107in x 60in x 46in
• Wheelbase: 68.5in
• Front Track: 52in
• Rear Track: 50in
• Weight: 795lbs (without driver)
                            Design: Chassis

             Engineering Specifications
• Static deflection – Less than .333”
• Torsional Rigidity – above -1500 ft-lbs/deg
• Wheelbase – between 60” and 70”
• Designed to fit 95 percentile person
• Withstand stresses under dynamic and static loading
  with factor of safety of 3
                           Design: Chassis

• Side Pods act as impact structure
• Upper side impact structure
  member attached too high to main
• As requested by Formula Hybrid,
  new cross member had to be
  constructed to protect driver
                                Static Analysis

    Deflection Analysis                 Static Stress Analysis

Max deflection: -.0098 inches           Max stress: 5361 psi
                                        Factor of safety:11.9
               Dynamic Stress Analysis

     • Using MSC ADAMS to get forces at A-Arm attachments
                     •Braking ( 60- 0 in 3 sec)
                     •Lane change at 50 mph
                 •60 mph radius turn of 343 feet
              •Applied loads in ANSYS to find stress

     Braking                                  Cornering

Max stress: 22126 psi                   Max stress: 16159 psi
Analysis Changes: Chassis
Torsional Rigidity Analysis

                              •Constrained back of
                                 frame and added
                               forces to front hoop
                              •Measured deflection
                                at nodes on hoop
                              •Calculated Torsional
                                    rigidity by:

                               4900 ft/lbs per degree
                 Manufacturing: Chassis

• Frame was constructed on campus
• Weld analysis proved welds will hold
• Intersections with many multiple welds were
  hardest to cope
               Lessons Learned: Chassis

• Have more than one designer
  on the chassis
• Design and analysis together
• Consideration of weight
  versus strength
                        Suspension Design

• Allow 1” travel jounce and rebound
• Achieve maximum tire contact at all times
• Optimize handling

  • Non-equal, Non-parallel A-arms
  • Push rod actuated coil-overs
  • Variable dampers
                    Suspension Design Specifications

Table 3.7: Front Suspension Geometry           Table 3.8: Rear Suspension Geometry
              Static Camber            -1.5˚                  Static Camber           0˚
      Camber Gain in Jounce       -.95˚/1"           Camber Gain in Jounce      -1.05˚/1"
   Camber Gain in Rebound          .89˚/1"         Camber Gain in Rebound       1.02˚/1"
                      Caster            5˚                           Caster           3˚
             Kingpin Offset        .915"                     Kingpin Offset          0.02"
         Kingpin Inclination            0˚               Kingpin Inclination          0˚
                      Toe In            0˚                           Toe In           1˚
          Ground Clearance              2"                Ground Clearance            2"
           Static Roll Center      1.23"                  Static Roll Center         1.34"
    Roll Center @ 1" Jounce        -.18"            Roll Center @ 1" Jounce          0.4"
  Roll Center @ 1" Rebound         2.65"          Roll Center @ 1" Rebound           2.75"
          Front Track Width            52"                Rear Track Width           50"
                   Front Suspension

                       Rear Suspension

                           COILOVER ACTUATION DESIGN

Suspension Adjustability

                 Shims between clevis

   Roll Center
                    Suspension Spring Rates


•    Nitrogen Charged
•    Adjustable damping in jounce and rebound
•    Preload adjustment
•    Cost effective

    Jupiter 5 by Risse Racing
                  Steering Geometry

• Rack and Pinion
• Lower rear placement
• Full Ackermann geometry
                   Testing and Improvements

• Final car setup and fine tuning
   – Ride Height
   – Camber
   – Toe

• Add anti-roll bars
• Add sensors
              Lessons Learned: Suspension

• Check more thoroughly for clearance issues
• Use proper bolts
• Change clevis design
Design: Differential

    • Brute Force Kawasaki ATV
      front differential
    • Limited Slip with a selectable
    • 4.375 gear reduction
                                 Differential & Mounting

•Tensile Yield Stress of Aluminum: 47000 psi
•3/8” thick aluminum
     •Max Von Mises stress: 33665 psi
     •Factor of safety of 1.3
                            Differential & Mounting

•Instead of remanufacturing with 1/2”
aluminum an additional mount was
•Max Von Mises stress: 25944 psi
•Factor of Safety of 1.8
              Design: Electrical Integration

• Warp 9” motor, 80hp peak, 140ft-lbs
• 32.3 continuous horsepower (versatile)
• 600amps, 144volts from Zilla 1K-HV (with power
• 2 min full throttle run time, 15min at 35mph
• Top Speed 85mph @ 6000 rpm
• Pic to PLC to LCD
                  Power Source & Containment Area

                               • Lead Acid Batteries 232lbs, 13.6
                                 usable Ah (17ah, up to 80%
                                 discharge) at 192V (Nominal)
                               • 16 cells, cost approx. $1500
                               • Odyssey PC680 Lead-acid batteries

• Diagonal Support tube thickness
increased to .095” (full X)
• Battery Layout
    Strapped together then strapped to
    Plexiglas to cover connections (with
    High Voltage Warning Label)
                                                      Odyssey Battery,
    Nomex fabric on walls and bottom for
                                                       Model PC680
    electrical insulation and fire protection
            Power Source & Containment Area

        • Full High Voltage Accumulator
             Dual Contactors default to Open
             3 Emergency Stop Buttons
             Fuse Backup
             High power lines outside Battery Area
            held in rubberized conduit

Ferraz-Shawmut                            Albright SW200
     Fuse                                    contactor
                   Design: Performance Calcs

• Motor, Battery, gear ratio combination was essential
• Excel Spreadsheet used to compare and optimize.
• Takes into account specs and calculates 0-60 time,
  voltage drop, runtime, and more.
• Final Configuration:
  0-60mph in 4.5 seconds (calculated)
                          Design: Brakes

• Design Criteria
  – Braking system that acts
    on all four wheels and is
    operated by single control
  – Two independent
    hydraulic circuits
• Alterations in Design
  – New master cylinders
    were purchased due to a
    leak in the old ones
                             Design: Brakes

• Design Calculations
  – To optimize handling the front
    wheels should lock up first in a
    full braking situation
     • To ensure this a bias was applied
       to master cylinders
         – Front 60% and rear 40%
  – Full Braking from 60 mph
     • Calculated stopping distance:
       124.73 ft
                 Design Changes: Steering Wheel
                                                        Previous Design

• Design Criteria
   – Must be able to hold the touch
   – Comply with SAE rules
   – Designed to be as light as
     possible while remaining rigid
     enough to protect touch screen    Current Design

   – Shaped for driver’s comfort
• Alterations in Design
   – Changed because of the
     method of mounting provided
     from manufacturer
   – Created a new wheel to be fully
     closed loop IAW SAE rules
               Design Changes: Steering Wheel

• Design Criteria
   – Structurally Rigid and
• Previous Steering Wheel
  did not fit design criteria
   – Also did not need touch
     screen for competition
            Design Changes: Acceleration Pedal
                                       Previous Design

• Design Criteria
  – Ergonomic to fit driver
  – Highly reliable
• Alterations in Design
  – Design Simplified to        Current Design
    increase reliability
  – More ergonomic for driver
                                Design: Safety

• Design Criteria
   –   Must have a 5-point or 6-point harness
   –   Driver Must Be Isolated from High-voltage
   –   Front Impact attenuator
   –   Side impact structure
   –   Must have at least 3 Large Emergency Shut Off buttons
• How we meet/exceed criteria
   – We have a 5-point harness that corresponds to Formula SAE
   – High-voltage wires are isolated in Side Pods and conduit outside
     of Side Pods
   – Impact attenuator fits FSAE regulations
   – Our Side Impact structure Approved Structural Equivalency
   – Two Emergency Shut off buttons on either side of roll hoop and
     one on driver’s dash board, also one main switch
   – Hairball Controller Interface allows user to limit power
                             Design: Safety

                                                   Main Switch
   Safety Harness

                       Emergency Stop Switches

                           Hairball – Controller
Safety Suit & Helmet                   Interface
                 Design: Impact Attenuator

•   HRH-10/OX – 3/16 – 4.0 HexWeb Honeycomb
•   7 – 1” layers separated by steel sheet
•   650psi Typical Stabilized Strength
•   Designed to absorb K.E. of 945lb, 15mph car &
    driver at less than 20G’s (capable of stopping
    greater mass than required by Formula Hybrid)
                            Design Changes: Body

• Body covers from front tip back to
  the main roll bar
• Side Pods fully enclosed
• Molded body to fit over front
  shocks and allow room for the
  impact attenuator
• Floor and side panels around the
  motor to protect the motor from

• Recommendations
    – Start Early
    – More than one committed
      person involved
                          Performance Testing

• Testing has been done for
  several different aspects of
  the car
   – Acceleration
   – Autocross
   – Endurance
• Testing still needs to be
  completed for
   – Braking
• Testing is also serving the
  purpose of acquainting the
  drivers with the handling of
  the car
                     Performance Tests:
                    Acceleration & Braking

• Tests were preformed
  to see if the car can
  reach the design
  specifications set with
  the higher weight
• These tests allow the
  drivers to learn the
  sensitivities of each of    Completed Testing Results
                             • Max Speed of 67 mph
  the pedal systems          • Test completed within 0.1 mile
               Performance Tests: Autocross

• This testing is used to
  demonstrate that the car
  can fulfill the turning
  radius requirements that
  have been set
• Autocross testing is also
  used so that the drivers          Completed Testing Results
  know how the steering       • Slalom runs completed to test the
                              suspension and steering
  will handle                 • Resulted in sheered grade 2 bolts,
                              all bolts replaced with grade 8 bolts
                  Performance Tests: Endurance

• The endurance testing
  serves the purpose of
  finding out how long the
  batteries will last under
  constant draw

• This section of the testing
  will also allow the team to
  find out how long it will take
  to charge the batteries                Completed Testing Results
                                   • Time lasted : 20 minutes at 10 mph
  during the halfway point of
                                   • Resolution: larger controller and more
  the endurance race at            batteries
                           Testing: Conclusions

• The testing that has been performed on the car has
  shown that we meet the design specifications for
   – Turning Radius
   – Maximum power available between 20 and 40 mph
• We do not meet the requirements for
   – Lightweight (under 650lbs with driver)
• We expect to meet, but have not yet tested
   – Acceleration from 0 to 60 mph in under 5 seconds (4.5seconds –
   – Top speed of 80 mph (85mph - calculated)
   – 15 minute battery life (at constant speed of 35mph)
                     Project Management:

Primary functions
• Budgeting
• Funding/Sponsors
• Scheduling
• Managing a Team
• Assigning Tasks

     Drive System                 Vehicle Dynamics            Chassis and Body
DC Motor              $1,600    Chromoly Tubing      $86    Chromoly Tubing      $740
Controller            $2,860    Spherical Bearings   $460   Fiberglass           $80
Lead Acid Batteries   $1,440    Brakes               $160   Shielding            $180
Potentiometer         $76       Tires                $680   Nomex                $80
Differential          $700                                  Miscellaneous        $250

Battery Management             PLC and Touch Screen             Driver Interface
PC Boards             $150     PLC and Modules       $286   Safety Harness       $180
00 Guage Wire         $80      Touch Screen          $810   Driver Accessories   $430
Master Switch         $155     Speed Sensor          $55    Miscellaneous        $200
Contactor             $240
Fuses                 $66
Miscellaneous         $300


       Sponsors:           Programs:                          Personnel:
•USA                •Pro/Engineer Wildfire 3.0   •Dr. Larochelle – Team Advisor
•Grassroots EV      •ANSYS                       •Dr. Grossman – Team Advisor
•US Didactic        •ADAMS                       •Larry Buist – Electrical Support
•Charles Whalen     •OrCAD                       •Bill Bailey – Shop Supervisor/Welder
                    •EZ Touch – EZ Panel         •John Amero – Machinist
•Bob Steele Chevy   Enhanced
                                                 •Bill Battin – Technical Support
•FLEAA              •EZ PLC Editor
                                                 •Stephanie Hopper – Lab Director
•CV Restoration     •LabView
                                                 •Frank Leslie – Public Relations/EV
•C2 Design          •PIC Basic                   Advisor
• Brevard Rentals

• Scheduling
    Design completion
    Give ample time for testing
• Managing a Team
   • Set goals high
   • Keep the team going but give some time to relax
• Assigning Tasks
   • Don’t overload one person to a task
   • Assign tasks to the appropriate person
              Lessons Learned

• Interdisciplinary cooperation
     - Start early with incorporation of electrical
     - Stay in communication
     - Introduce each other systems to the other group
• Leave enough time for testing and troubleshooting
• Keep drawings updated as soon as something
                     Lessons Learned

Recycling of components
-Cost saving
-time savings
                             -Steering pinion gear
                             -Wheel Brakes

• Anti-roll bars
• Data Logging

            • Keep the car fully electric
            • Run true performance tests
            • Keep electrical engineers on the team
                       Future Improvements

• To Do:
  –   Build Battery Management System
  –   Check and Adjust Differential Mounting
  –   Improve Real World Motor Performance
  –   Locate Li-Ion/Li-Polymer Sponsor
  –   Evaluate BMS (Battery
      Management Systems) options
                       Future Improvements

For Future REV Form
• Schedule testing time on a real track
• Reintroduce Lithium Ion batteries as power source
• Reincorporate PLC control system
• Expand on sensors
         - Temp, speed
         - efficiency
• Increase Data collection for evaluation of performance
                       Future Improvements

For Future Formula Hybrid
-Use IC as power generator
-Use electric engine for propulsion
-Reconsider Capacitors for rapid charging and discharging cycles
-Redesign frame to fit all components

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