Project Overview Primary Goal – Design and build a working electric vehicle Accelerated design...

Ram Racing

2014-2015Colorado State University

Formula SAE

Project Overview• Primary Goal–Design and build a working electric

vehicle

• Accelerated design cycle–Modification of previous designs

Project Overview• 1st electric vehicle for Ram Racing– Create the platform for future years of Ram Racing

to iterate on

• Integration of electrical and mechanical engineers– Adds expertise of electrical systems which will

allow addition of more complex systems like:• Regenerative braking • The use of high voltage systems

Background• FSAE is the largest international competition

involving engineering and automotive design• FSAE competition is comprised of 7 scored events

Static Events include:• Cost report• Design Judging• Presentation

Dynamic Events include:• Acceleration• Skidpad• Autocross• Endurance

Background• Progression of cars

2011 CSU FSAE RR112013 CSU FSAE RR13

2007 Ram Racing FSAE RR07 2012 CSU FSAE RR12

Photo courtesy: Ram Racing




Design ConstraintsConstraint Method of Measurement Limits Driving

FactorWheelbase Length in inches: from the centerline of front to rear

tires>60in. FSAE Rule

T2.3

Track Width Width in inches: from the centerline of side to side tires

>75% front track to rear track

FSAE Rule T2.4

Power Output Kilowatts: Drawn from high voltage battery <80kW FSAE Rule EV2.2

High Voltage Battery Pack

Volts: overall voltage from any two points 300 V DC Max FSAE Rule EV1.1.2

Roll Plane Measured by tangent line between Main and Front Roll Hoops

2in, min clearance to

driver helmet

FSAE Rule T3.10.3

Suspension Inches of bounce and jounce 1in in both directions, min

FSAE Rule T6.1

Battery Pack Pack must withstand external loading 20g long. 20g lat

20g vert

FSAE Rule AF4.8.2

Safety Determined by Electrical safety officers Determined by Technical Inspectors at FSAE

For Car safety to prevent Serious injury or death

0 FSAE Rules/ Team Driven

Design ObjectivesObjective Priority

Rating5-Highest1-Lowest

Method of Measurement (Theoretical)

Method of Measurement

(Actual)

Objective Direction

Target

Battery Pack Capacity

4 Hand calculations, lap simulations

Endurance simulation at test site

increase +10% of endurance

distanceBattery Pack

Mass3 Spec Sheet with

hand calculationsScale decrease <140lbs

Compared to other FSAE EV

teams batteries

Lap times: Autocross

1 Lap simulations Vehicle testing details TBD

decrease < 1min 20sec from the Michigan 2013

track layout

Endurance Completion

5 Lap simulations 22km endurance test increase +10% of endurance

distanceLight Weight 1 Hand calculations Scale decrease <700lbs w/out

driver

Design Summary• Due to the complications of integrating an

electric drivetrain, the team has decided that getting the car done early is the biggest concern– Getting the car done earlier will allow for more

testing time– The electrical system will be tuned primarily based

off of driver feel

Final Concept

Image: Ram Racing

Final Concept

Units(Deg)

• Function– Main structure– Protects driver– Transmits loads

• Feasibility– Modeling in CAD– Installed torsional stiffness test

• DFX– Manufacture– Packaging– Safety

• Details– FEA stiffness: 998 lb-ft/deg– 17% correction factor (overestimate):

828 lb-ft/deg– Mass (est.): 90.7 lbs

• Tubes: 83.7 lbs• Filler Rod: 2 lbs• Tabs: 5lbs

Image: Ram Racing

Image: Ram Racing

Final Concept (FMEA)# Item and

FunctionPotential

Failure Mode

Potential Effect(s) of

FailureSEV Potential Cause(s)/Mechanism(s)

of Failure OCC Current Design Controls DET RPN Recommend Actions

1Chassis Primary

StructureWeld Failure

Disabled Vehicle,

Driver Injury, Loss of Control

10 Bad Weld Quality 6 Visual Inspection 4 240 100% Inspect All

Chassis Welds

2Chassis

Secondary Structure

Motor Support Failure

Driver Injury, Damage to

other systems

10 Bad Weld Quality, Incorrect Geometry 6 Visual

Inspection 4 240 100% Inspect All Chassis Welds

3Chassis Primary

StructureTube Failure

Loss of Stiffness,

Damage to Other

Systems

6 Undersize Wall Thickness in Tube 4

Manufacturer Certifications,

Visual Inspection

7 168100% Inpsect all

Chassis Tubes Before Welding

4Chassis

Secondary Structure

Tab Failure

Damage to Other

Systems, Loss of Control

7 Bad Weld Quality, Incorrect Geometry 6 Visual

Inspection 4 168 100% Inspect All Chassis Welds

5Chassis Tertiary

Structure

Battery Support Failure

Driver Injury, Diasbled Vehicle

10 Bad Weld Quality, Improper Support 2

Visual Inspection,


Additional Battery

Containment

5 100 100% Inspect All Chassis Welds

Final Concept (Budget)Chassis Budget Cost Source Donation?

Chassis Tubes and Profiling $2,900 Cartesian VR3 No

Remachining Fixture Plates $500 Woodward Yes

Fixturing Stock $400 McMaster No

Fasteners $100 Suburban Bolt No

Welding Filler $100 Arc-Zone No

Tab Stock $100 Online Metals No

Total: $6,600

Cost After Donations: $3,600

Final Concept• Function

– Keep tires in contact with pavement– Keep tires in condition for optimum

accelerations• Feasibility

– Modeling in CAD/FEA– Optimum Kinematics Analysis

• DFX– Manufacture– Reliability– Performance

• Accelerated Design Cycle– Adaptation of design features from last 3

years

Creo Solid Model Optimum K Kinematics Model

Image: Ram Racing Image: Ram Racing


FunctionPotential Failure

Mode


FailureSEV

Potential Cause(s)/Mechanism(s) of

FailureOCC

Current Design

ControlsDET RPN Recommend

Actions

1Outer

Suspension Ends

Stress Concentration in Bending

Damage to other systems, Loss of control

10 Manufacturing Error 1 Visual Inspection 2 20 Inspection by

recipiant

2 Uprights Stress Concentration in Bending


8 Manufacturing Error 2 Visual Inspection 7 112 Inspection by

recipiant

3 Rockers Panel Delamination Damage to

other systems, Loss of control

8 Manufacturing Error 1 Visual Inspection 6 48 None

4 Carbon Tubes Buckling/Bending Damage to

other systems, Loss of control

10 Incorrect Geometry 1Pre-testing

Visual Inspection

5 50Pre and Post-

Testing Inspection

5Pull/Push Rod

Tubes & A-arm Tubes

Adhesive Failure in Shear


10 Improper Bonding Procedure, Insifficient Bonding Area 4 Visual

Inspection 7 280Tighter Control

of layup process

Final Concept (Budget)Suspension Budget Cost Source Donation?

Brake Discs $200 In house NoBrake Pads $75 In house No

Brake Calipers $150 In house NoBearings (spindle) $150 SKF No

Bearings (rod ends) $400 Aurora NoCarbon tubes $200 In house No

Stock $200 Metal Distributor NoTires $170 x 4 Hoosier No

Dampers $1,720 In house NoSprings $250 In house NoTotal: $9,025

Cost After Donations: $1,430

Final Concept• Function:

– Transfers Torque to rear wheels– Accelerates car

• Feasability: – Modeling in CAD– FEA analysis

• DFX:– Efficiency– Reliability– Packaging

• Details:– Torque: 210 Nm– Chain pull 6700N– 4:1 gear ratio– Up to 80% Torque bias to one wheel: 624

NM

Image: Ram Racing

Image: Ram Racing


FunctionPotential

Failure Mode


FailureSEV Potential Cause(s)/Mechanism(s)

of Failure OCC Current Design Controls DET RPN Recommend

Actions

1 Half Shaft Torsional Shear

Disabled Vehicle 8 Poor design, Machining

Imperfections 4FEA, Previous

cars' Performance

9 288 FEA, Stronger Spares

2 Chain Elongation, Break

Disabled Vehicle 8 Improper Maintenance/tensioning 2 Professional

Help, Math 6 96 Spare Sprockets, Spare Chain

3 Differential Mounts

Fatigue, Bending,

Shear

Disabled Vehicle 8 Poor design, Machining

Imperfections 3 FEA 7 168Spare Mounts,

Material Evaluation

4 Motor Mounts

Fatigue, Shear

Disabled Vehicle, Driver

Injury10 Poor design, Machining

Imperfections 3 FEA 7 210Spare Mounts,

Material Evaluation

5 Motor Cooling Oil Starvation

Disabled vehicle, Motor

Failure8 Improper Flow Rate, Pump Failure 2

Specialty Pumps,

Professional Help

2 32Monitor Pumps Closely, Safety

Shutoff

Final Concept (Budget)Drivetrain Budget Cost Source Donation?

Motor $9,000.00 Remy, Inc YesDifferential $1,000.00 HPF Performance No

Inboard Tripod Carriers $370.00 RCV NoTripods $140.00 RCV No

Cooling Pumps $1,000 Meziere YesHalf Shaft Stock $300.00 Metal Distributors No

Aluminum Mount Stock $200.00 Metal Distributors NoChain $60.00 Ebay No

Sprockets $120.00 Sprocket Specialists No

Total $12,190.00

Cost After Donations $2,190.00

Final Concept• Function

-Drivetrain power• Feasibility

– Modeling in CAD– Circuit schematics

• DFX– Packaging– Safety

• Details– 72S2P battery back– 300Vdc max, 266Vdc

nom.– Capable of 375Adc

continuous– Safe under failure

– Weight: Est 104 lbs – 7.5kW hrs Image: Ram Racing

Image: Ram Racing

Final Concept (FMEA)# Item and Function Potential Failure

ModePotential Effect(s)

of Failure SEV Potential Cause(s)/Mechanism(s) of Failure OCC Current Design Controls DET RPN Recommend Actions

1 Battery Cell for energy storage Single cell failure

Higher chance of failure in parallel cell counterpart

2Neglect, exceeding rated specifications, poor cell

construction3 Battery management

system monitoring 2 12Handle with care,

operate within specifications

2

Battery Management

System for monitoring cells

Voltage, Current, or

Temperature sensing failure of 25% of cells

Fire, cell abuse, Estimation of

sensed parameters

(done automatically

by BMS)

10 Exceed lifetime, bad soldering, extreme vibration 2

Visual inspection, isolate cell boards

from vibration along with cells

7 140 Inspect all solder work

3

High voltage controller for

controlling the motor

Control system failure

Vehicle shutdown 8 Misuse/neglect 1 Care is to be taken

with the controller 2 16Handle with care,


4 Battery Cell for energy storage

Two parallel cell failure

Sudden loss of all power 8

Neglect, exceeding rated specifications, poor cell

construction2 Battery management

system monitoring 2 32Handle with care,


5

High voltage controller for

controlling the motor

HV cable disconnection

Driver injury, total loss of power, fire

10 Improper torque for connection 2 Check all torque

specifications 6 120Check torque

applied to connection point

Final Concept•Function

–Technical Inspection–Safety shutdown circuitry–Power various sensors

•Feasibility–Circuit schematics

simulations–Test and retest circuits for

faults•DFX

–Build/wire circuits–Safety

Image: Ram Racing


FunctionPotential

Failure Mode


FailureSEV

Potential Cause(s)/Mechanism(s) of

FailureOCC Current Design

Controls DET RPN Recommend Actions

1Torque

Encoder Accelerometer

Sensor Failure Loss of Control 6 Sensor mounting error, loose wire/connections 4

Visual Inspection,

Sensor fault test3 90

Tighten connections, test with multimeter

2 Brake Encoder Brake Sensor Failure Loss of

Control, 6 Sensor mounting error, loose wire/connections 4

Visual Inspection,


Tighten connections, test with multimeter

3

Arduino Mega Microcontrolle

r for low voltage controls

Programming/ Power Failure

Loss of Control, Signal error to motor

controller

6 Loose connections, lose of power 5

Visual Inspection,

Inspection of programming

code,

4 144

Tighten connections, test with multimeter, review program

for errors

4 Sensata Crash Sensor Sensor Failure

Driver Injury, due to

improper shut down of tractive system

10 Impact upon crash does not activate sensor 5

Visual Inspection,


Shake the sensor to see if it opens

the circuit

5

Bender Isometer Insulation

Monitoring Device

Tractive and Grounded low voltage system desegregation/

Sensor fault

Driver Injury, Potential

shock10 No seperation between tractive

and grounded low voltage systems 6

Visual Inspection,


Sensor fault test

6 360

Check with multi-meter to see if

tractive and grounded low

voltage systems are isolated

Final Concept (Budget)Controls Budget Cost Source Donation?

HV Cables $400 Champlain Cable Yes

HV Controller $5,250Rinehart Motion

Systems No

Batteries $12,500 Melasta Part Sponser

Bus Bar $250Storm Power Components No

Batter Management System $1,624 Elithion No

Torque/Brake Encoder $229 x 3 XT Racing No

Arduino Mega 2560n M3 $28 Ardunio Yes

Misc. Components $500 Various Mix

Total $21,239

Cost After Donations $20,311

Validation Plan•Majority of parts for final assembly or testing have been ordered or are currently on hand

•Assembly ongoing through winter break

Image: Ram Racing

Image: Ram Racing

Validation Plan• Evaluation

– CAD

– Hand Calculations

– Modified Ram Racing Designs

– Road Testing

– Simulation• Safety Circuit

– Specific Component Testing• Impact Attenuator

• Battery Cell

Image: Ram Racing

Image: Ram Racing

Term II Work-Plan• Main Goals– Finish manufacturing and assembly of vehicle– Begin testing and data collection of vehicle

• Secondary Goals and Contingency –Refine and fix any design flaws–Rework on systems that fail, break, or do not

work as intended

References• [1] SAE International. (2014, September 1). 2015 Formula SAE®

Rules [Online]. Available:http://www.fsaeonline.com/content/2015-16%20FSAE%20Rules%20revision%20in%20progress%20kz%2083114.pdf

Ram RacingAny Questions?

Project Overview Primary Goal – Design and build a working electric vehicle Accelerated design...

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