Milestone 2: Project
Proposal
E.E Advisor : Dr. Li
Team Members:
Tomas Bacci
Danny Covyeau
Scott Hill
Stephen Kempinski
George Nimick
Sam Risberg
M.E. Advisor : Dr. Shih
Proposed Design
Overview
 Electric Category
 Mechanical – braking, chassis, suspension and steering
 Electrical – motor design and battery management
 Direction
 Feasibility, tangibility, and budget
 Constraints
 Budget, rules
University of Texas, Arlington
Nearly every vehicle from 1984 - 2008
Project Management
 ME Systems
 EE Systems
 ME Leader – George Nimick
 EE Leader – Scott Hill
 Chassis – George Nimick and
Sam Risberg
 Motor Control and Design
– Danny Covyeau
 Braking – Sam Risberg
 Battery Management and
Accumulator Design Scott Hill
 FEA – George Nimick and
Tomas Bacci
 Steering and Suspension –
Stephen Kempinski and
Tomas Bacci
EE Top-Level Diagram
Propulsion/Motor Design
Propulsion
 4 electric motors, one on each wheel.
 Mounted onboard the vehicle (i.e. not ‘in-wheel’ or ‘hub’ motors)
 Each motor will have its own gear reduction so as to limit the top speed
of the vehicle as well as increase the mechanical torque.
 2 motor controllers, 2 motors per controller
 1 controller for two front motors
 1 controller for two rear motors
 Motors will be wired in a series configuration
 2 HV battery packs, 1 per controller
 Will help distribute the weight evenly between the front and rear of the
vehicle.
Why AWD?
 Traction at all four wheels
 Cornering Stability
 Load Transfer
 Deceleration
 Regenerative Braking Advantage
 Acceleration
 AWD biased towards the
rear wheels
 Formula SAE Dynamic Events
 Autocross
 Average Speed: 25 – 30 mph
 Endurance
 Average Speed: 29.8 – 35.4 mph
 For more information see:
 http://autopedia.com/stuttgart-west/Physics/StuttPhysics01.html
http://www.motortrend.com/roadtests/sedans/11
2_0506_front_rear_allwheel_drive/viewall.html
Electric Drive
 The electric motors must work with one another in such a way to
safely, efficiently and quickly propel the vehicle.
 The motors should all be the same make and model to simplify the
design.
Item
Cost
Motor
$ 1595.00
Quantity
Shipping
3 $
Total
130.00 $ 4915.00
Electric Motors
Robotmarketplace.com
Agni 95-R
 Permanent Magnet
 72 VDC
 400 Amp peak
 93% Peak Efficiency
 30 peak horsepower
 Only 24 lbs
 6000 rpm max
rotational speed
Motor Controllers
 The motor controllers should be able to
control two motors in series simultaneously
 Regenerative Braking built-in
 The motor controller selected should be
specifically built for the type of motor chosen
(i.e. ac induction, series dc, etc).
 It should be able to handle at least twice the
rated voltage of the motor and the same
maximum current of the motor.
Item
Cost
Controller
$ 1300.00
Quantity
Shipping
2 $
Total
60.00 $ 2660.00
Cloudelectric.com
Motor Control System
 The motor control system will consist of two permanent magnet motor
controllers.
 One will control the front motors while the other will control the rear motors.
 The motors in the front/back will be connected in a series configuration such
that a single controller can operate both motors simultaneously.
 This will not only simplify the design but will also create somewhat of a differentiallike effect for the front and rear.
 Separate battery packs
 One in the front and one in the rear to help create a better weight balance
between the front and rear.
 These packs will be wired in parallel with one another to maintain a constant
potential difference between the front and rear controllers and so that there is a
common ground.
Throttle Control
 The throttle should directly affect the vehicles speed
and/or torque.
 Theory:
 Accelerator pedal called a pot box or potentiometer box.
 Sends an analog signal to the ECU.
 The ECU will then plug this signal, along with signals
from each motors RPM sensor, the brake pedal, and
other sensors into an algorithm that will determine what
analog values to send to both the front and rear motor
controllers.
 The front and rear controllers will receive different
signals depending on the
amount of torque desired
at either end.
Cloudelectric.com
Battery
Management/Accumulators
Accumulator
Hobbyking.com
 Lithium Polymer Batteries
Picture Courtesy Danny Covyeau
 Voltage Per Cell : 3.7V
 Desired Pack Configuration: 3S String with 11.1V per pack
 Chosen because desired voltage for each motor controller is 144V
and in series it takes almost exactly 13 batteries to achieve this
voltage
 Due to competition rules (fusing parallel connections) the
team cannot easily use packs that are internally wired in
parallel. Therefore packs such as 3s2p that would achieve
higher than 8Ah per pack cannot be used.
Battery Characteristics
 Maximum Capacity : 5,400 Wh
 With a voltage of 144V current capacity of 37.5Ah is required to be at
the maximum
 This is before efficiency is taken into account though so a current
capacity of 40Ah will be used.
 With a current capacity of 40Ah our vehicle will require a total of
8 parallel strings if 5Ah batteries are used.
 If 5.8Ah batteries are used the we could get away with 7 parallel
strings, This would save us 13 batteries!
Battery Capacity
5 Ah
5.8Ah
Cost Each*
~$28.08
~$36.97
Total Batteries Needed
104
91
Total Cost of Batteries
~$2920.32
~$3364.27
*Prices based off of
hobby king
Retail website
Battery Discharge Simulation
Simulation Schematic 13s8p configuration
(actually 39s8p configuration with 3s packs)
Battery DischargeSimulation
(Cont). Simulation with a 5Ω Resistive Load Without SOC Measurement
Voltage Reading
Operating Region
Current Reading
Capacitors
Picture Courtesy Danny Covyeau
 Capacitors are being considered for the vehicle in order to
take advantage of regenerative braking function included in
the controller Danny talked about previously.
 According to the Formula Hybrid SAE 2012 Competition
Rules “Endurance courses will be configured, where possible,
in a manner which maximizes the advantage of regenerative
braking.”
Battery Management System
 The 2009-2010 teams car used a e-lithion Lithiumate pro
BMS.
 To our knowledge the BMS is working and will be used in the
2011 car for purposes of budget
 More research needs to be done on the on the Cell boards
BMS Master
Cell Board
Elithion.com
Picture taken from 2009-2010 Car
Battery Charging System
 The battery charging system for this years team will need to
be much larger than last years since the vehicle is fully
electric
 The proposed charger is the “Battery Charger HWC4 Series
Charger High Output 144V/15A 220VAC Input”
 This charger also has a variable charge mode if battery
configuration needs to be changed in the case of a large
failure in the accumulator system
PLCcenter.com
Cloudelectric.com
Accumulator Enclosure
 A clear polycarbonate insulating material will be used to
construct the accumulator enclosure
 This material will allow for easy inspection at the competition
 This material allows proper insulation of the HV accumulator
and the frame of the vehicle
Newegg.com
TapPlastics.com
Accumulator System Budget
Item
Quantity
Batteries
108
$28.08
~$100
$3124.40
BMS Master
1*
$413
~$25
$428
BMS Cell
Board**
TBD
TBD
TBD
>$500
Battery Charger
1
$700
~$25
$725
Accumulator
Enclosure
1
$75
~$20
$95
Total
** Company Needs
to be contacted for
pricing
Price Per Shipping
Total Cost
>$4872
*Already Have 1 BMS
master from 2009-2010
Team (Need 2 total)
Timeline
Nov 1
Dec 1
Feb 1
Jan 1
Pick &
Order
Batteries
Mar 1
Finish
Research on
BMS & Order
Polycarbonate
Abuse Test &
Design
Accumulator
Enclosure
Create
Accumula
tor
Enclosure
Create
Battery
Packaging
& Wiring
Test Battery
Charging
System as a
whole
Test System as
a Whole
ME Top-Level Diagram
Chassis
Constructing the chassis
 Strong Enclosure and component platform
 The chassis will house the driver and a strong enclosure is
required to ensure safety
 The chassis will not only need to be aerodynamics, but should
have a ideal weight distribution and center of gravity
 Perform FEA
Chassis Ergonomics
 Mounting for:








Brakes
Suspension
Motors
Driver accommodations
Safety equipment mounting
Steering
Body panels
Batteries
Chassis Budget
Cost
Part Name:
Quantity
Shipping
Total
Sheet metal (Al)
$
284.80
3.00 $
25.00 $
879.40
Structural tubing
$
53.11
25.00 $
50.00 $
1377.75
Conduit
$
3.00
100.00 $
40.00 $
340.00
Honeycomb (Al)
$
250.00
15.00
515.00
2.00 $
Total:
$
$ 3112.15
Chassis Timeline
Research
Materials
and
Feasibility –
Oct. 15
Preliminary
Chassis
Design –
Oct. 31
Review
Rules,
Ergonomics
and Fitment
– Nov. 15
Conduct
FEA – Nov
30
Finalize
Model –
Dec. 15
Build
Chassis –
Feb. 15
Testing and
Review
Rules –
March 31
Steering
speedwaymotors.com
Steering
 Goal
 Control direction
 Selection
 Mechanical (Rules)
 Less than 7 degrees of
free play
 Choices: rack and pinion,
recirculating ball, worm
and sector, articulated
steering and four wheel
steering
 Constraints
 Effectiveness
 Practicality
 Cost
 Choice: Rack and
Pinion
 Installation
 Non-binding
 Driver operation
 Steering shaft
Steering Timeline
Major
Design of
Chassis and
Suspension
– Nov.15
Research
and
Selection –
Nov 30
Preliminary
Design –
Dec.15
Solid Model
and Fitment
– Jan 15
Source
Parts – Jan.
22
Install and
Test – Feb.
29
Estimated Budget for Steering
Item
Cost
Qty. Shipping
Total
Steering Wheel
$192.02
1
$15.00
$207.02
Steering Quick Release
$129.99
1
$4.00
$133.99
Rack and Pinion
$96.95
1
$8.00
$104.95
U-Joints
$28.00
2
$5.00
$61.00
Rod Ends
$12.14
4
$8.00
$56.56
Tubing
$27.83
1
$8.00
$35.83
Hex Stock
$17.95
1
$2.00
$19.95
Total:
$619.30
Braking
Braking system
 Single control to ensure safe stop on four wheels
 -We will have one pedal acting on four wheels
 -A master cylinder will multiply the pedal force into a hydraulic
force
 Two independent hydraulic circuits
 One circuit will control the rear wheel braking the other the front
 This will ensure if one circuit fail another will be in place
 Safety will be the main concern for this system
Braking Continued
 Brake line Durability
 We won’t be using a factory rubber brake line
 Stainless Steel braided line will prove more durable for racing
situations and heat produced from the extreme conditions
 Testing the brakes
 To test the systems we will apply maximum pressure to the brake
pedal at a high speed and ensure all four wheels lock up as stated
in the FSAE Hybrid rules.
Braking System Budget
Cost
Part Name:
Quantity
Shipping
Total
Brake Lines (Steel Braided)
$
52.32
6.00 $
5.00
$
318.92
Brake Fluid
$
19.99
1.00 $
-
$
19.99
Brake Caliper
$
37.94
4.00 $
10.00
$
161.76
Brake Rotor and pads
$
215.68
4.00 $
10.00
$
872.72
Total:
$1373.39
Braking timeline
Research
and
Selection –
Oct. 31
Measure
dimensions
and needed
lengths –
Nov. 15
Design brake
components
in
SolidWorks
– Nov. 31
Mock parts
to chassis
and check
clearance
with
suspension –
Dec. 8
Source Parts
– Dec. 15
Install and
Test for 4
wheel lock
up – March
31
Suspension
Competition Constraints
 3.2.1 Suspension
 fully operational suspension system with shock absorbers,
front and rear
 usable wheel travel of at least 50.8 mm (2 inches), 25.4 mm
(1 inch) jounce and 25.4 mm (1 inch) rebound, with driver
seated.
 3.2.2 Ground Clearance
 with the driver aboard there must be a minimum of 25.4 mm
(1 inch) of static ground clearance under the complete car at
all times.
Competition Constraints Continued…
 3.2.3 Wheels and Tires
 3.2.3.1 Wheels
 The wheels of the car must be 203.2 mm (8.0 inches) or more in
diameter.
 3.2.3.2 Tires
 Vehicles may have two types of tires as follows:
 Dry Tires – The tires on the vehicle when it is presented for
technical inspection are defined as its “Dry Tires”. The dry tires
may be any size or type. They may be slicks or treaded.
 Rain Tires – Rain tires may be any size or type of treaded or
grooved tire provided:
Understanding Vehicle Dynamics
 Weight transfer – actual movement of the vehicle CoM relative to the wheel axes due
to displacement of the chassis as the suspension complies.
 Downforce - downwards thrust created by the aerodynamic characteristics of a car.
 Roll center - the notional point at which the cornering forces in the suspension are
reacted to the vehicle chassis/body.
 Camber – angle of the wheel relative to vertical.
 Caster – angle to which the steering pivot axis is tilted forward or rearward from vertical
 Toe – angle that each wheel makes with the longitudinal axis of the vehicle
 Pitch - front and rear of the chassis go in opposite directions.
 Yaw - rotation of the car in a horizontal plane around a vertical axis.
 Heave - movement of the diagonally opposed wheels in opposite directions
Set up accuracy
 Dependent on:
 Springs
 Shocks
 Camber
 Caster
 Toe
 Tire pressure
 Ride height
 Wings
Independent Suspension
 Better ride quality
 Improved handling
 fully adjustable
SLA Double Wishbone
 Short Long Arm Suspension
 Lower A-Arm is longer than
the Upper A-Arm
 Reduced changes in camber
angles
 Reduces tire wear
 Increases contact patch for
improved traction
Connection to Sprung Mass
 Predetermined geometry points
 Chassis may be modified
to accommodate
 Mounting brackets
welded to chassis
Connection to un-sprung mass
 Spindle design
 Regenerative Brake
assembly
 Steering connection
 Wheel hub and bearing
 Wheels/Tires
Connection to un-sprung mass
Continued
Push rod, spring, damper
 A push rod will transfer suspension
forces to coil-overs mounted to the
chassis
-Reduces amount of un-sprung weight as the
springs and shocks move in-board
-Spring compression rate can be controlled
with a bell crank
-Increased aerodynamics for open wheel
application
Push rod, spring, damper
Continued
 Linkage will be set up so as wheel travel increases, the rod will
come closer to a 90 degree angle with the shock absorbers,
increasing the efficiency of the shocks
- Suspension stiffens with wheel travel
 A bell crank can allow you to place shocks horizontally if needed
Test Plan
 Observe
 Measure
 Analyze
 Simulation
 Predict changes
 Improve performance
Suspension - Budget
Part
cost
quantity shipping
total
Aluminum
Block
$324.85
1
20
$344.85
Rod ends
$12.14
32
8
$372.20
springs
$45
4
10
$190
shocks
$675
4
20
$2720
Wheel Hub
34.99
4
15
154.96
Aluminum
Block
$323.85
1
20
$343.85
4130-steel
tubing
53.11
10
25
$556.10
Total
$4671.96
Suspension-time line
Objective
Completion Date
Research
In Progress
Preliminary Design
November 14, 2011
Model
November 30, 2011
Determining final geometry
December 7, 2011
Connection to sprung mass
December 14,2011
Wheel Hub/spindle design
December 20, 2011
CAD compile
January 15th 2011
Final Product Build
March 15st 2012
Risk Assessment
 Risks associated with our design include:





Individual Component Failure
Unresolved Options in Design
Sick Team Member(s)
2012 Formula Hybrid Rules Document Non-compliance
Budget Miscalculation
Important Project Deadlines
Senior Design
 Milestone 3: Conceptual Design Review
Date due
11/14/11
Competition
 Registration Deadline (completed)
 Competition forms
 Structural Equivalency Form
 Impact Attenuator Data
 Design Report & Spec Sheet s
10/04/11
01/30/12
02/27/12
04/09/12
The 2012 Formula Hybrid Competition begins April 30th 2012.
ME Budget Proposal
Part Name:
Penske Shocks
Suspension springs
Hoosier Tires (Dry)
Hoosier Tires (Wet)
Rims
Rod Ends
Brake Lines (Steel Braided)
Brake Fluid
Brake Caliper
Brake Rotor and pads
Wheel Hubs
Rack and pinion
Steering wheel
Steering wheel quick release
Block of Aluminum
Sheet metal (Al)
CV Axle
Sheet metal seat
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
Cost
675.00
45.00
208.00
213.00
113.00
12.14
52.32
19.99
37.94
215.68
34.99
96.95
192.02
129.99
323.85
284.80
72.78
115.95
Quantity
4.00
4.00
5.00
5.00
10.00
30.00
6.00
1.00
4.00
4.00
4.00
1.00
1.00
1.00
1.00
3.00
4.00
1.00
Shipping
$
20.00
$
10.00
$
35.00
$
35.00
$
70.00
$
8.00
$
5.00
$
$
10.00
$
10.00
$
15.00
$
8.00
$
15.00
$
4.00
$
20.00
$
25.00
$
15.00
$
15.00
Total
2,720.00
190.00
1,075.00
1,100.00
1,200.00
372.20
318.92
19.99
161.76
872.72
154.96
104.95
207.02
133.99
343.85
879.40
306.12
130.95
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
$
Total:
$10,291.83
Joint Budget Proposal
**The Total Direct
Costs is the actual
cost of the project
since expenses such
as personnel and
fringe benefit costs
are not actually
being paid.
References
 http://www.carbibles.com/suspension_bible.html
 http://cmrr.ucsd.edu/people/talke/documents/Fornace_Thesis_8
_31_06.pdf
 http://formula-hybrid.org/pdf/Formula-Hybrid-2012-Rules.pdf
 http://www.m3post.com/forums/showthread.php?t=346660
 http://robotmarketplace.com
 http://cloudelectric.com
 http://hobbyking.com
 http://elithion.com
 http://plccenter.com
 http://newegg.com
 http://tapplastic.com
 http://speedwaymotors.com