Team Human Powered Vehicle

Team Human Powered VehicleTeam Human Powered Vehicle

This document is controlled information and is only reproducible with permission of Team HPV 1

Team HPV: A Quick Review

Prepared By:

Tyler Jandreau, Taylor Brown, Jamie Huffman, Joey Stine, Kevin Villa, Matt Strand, Kyle Chapman, Jimmy Woodard,

Adam Cooper


This document is controlled information and is only reproducible with permission of

Team HPV2

Objectives

“ Team HPV will design and build an aerodynamically and mechanically efficient vehicle that uses pure human power to achieve a top speed of at

least 61.5 mph.”

Top Level Objectives•Design and build a Human Powered Vehicle•Perform research to determine appropriate HPV design techniques•Document equations and techniques to use when designing the HPV•Perform necessary logical hand calculations to ensure subsequent design steps are accurate and valid• Use high-tech engineering techniques to validate results



Evolution of Requirements

To determine the validity of the requirements, we must first understand the needs of the product

• What will happen in a crash?

• How will this be built?

• How will this go the correct speed?

• Where will we test this vehicle?

• What is the time constraint?

• How can we ensure the efficiency of this vehicle?



Functional Requirements

To determine the success or failure of the HPV project, it is necessary to determine what the HPV has to actually do:

• HPV has to be completed before Senior Showcase, 2009

• HPV has to be rideable

• HPV has to have basic rider safety features

• HPV must be light enough for one rider to propel

• HPV shell must be puncture resistant and resist a specific point load

• HPV drive train must not have a mechanical loss of more than 5% of total input



Team Goals

The HPV team’s goals include:

Team HPV will assemble and build a vehicle to compete in the land speed challenge

Team HPV will perform all necessary calculations for success by hand

Computer tools will be used to verify previously completed hand-calculations

Success will be met by meeting ~80% of requirements



Calculations

δ = Fa2(3L - 4a)/6EI

The equations to the left were used to perform basic feasibility of the HPV to determine if the human body can break the 61.5 mph barrier

The equations to the left were used in the static analysis method for the joints.

The equation to the right was used for analysis on the frame. It is the equation for deflection of a beam with two free ends and a force in the middle. Also, standard deflection was used with one ridged end.

δ = FL3/3EI

wright.nasa.gov/airplane/drageq.html



Drivetrain Calculations

Feasibility calculations for drivetrain system were also preformed, showing HPV team that a minimum loss of power can be achieved with proper engineering:

27 inch wheel at 80 mph = ~ 1000 RPMAssume pedaling cadence of 100 RPM

Drivetrain must be able to meet or exceed 10:1 Ratio. Most ideally, 11:1

Calculations and analysis of CVT transmission showed that 11:1 is nearly impossible.

To obtain 11:1, manual production of a CVT must be facilitated, which exceeds groups ability in machine shop.

Hybrid drive train system developed, using half belt, half chain mechanisms for power transfer

Team Human Powered Vehicle

This document is controlled information and is only reproducable with permission

of Team HPV8

700x23mm Series Wheels

Dia (in) Md-Drv Ratio Crank Pulley 3.5001.750 Unit Conversion Mid Drive Pulley 2.000 12.781 # of Teeth Ratio Overall Ratio Speed (mph)

Chain Ring 53.000 Cassette 1 34.000 1.559 2.728 21.344 10.672<- Min Start speed

2 24.000 2.208 3.865 30.237 18.445<- Optimal Overlap3 21.000 2.524 4.417 34.557 37.566 <- 88 rpm at same above speed4 17.000 3.118 5.456 42.688 5 15.000 3.533 6.183 48.380 6 13.000 4.077 7.135 55.823 7 11.000 4.818 8.432 65.972

Wheel Dia (in) 26.300 Wheel Rad (in) 13.150 Circumference (in) 82.624


DrivetrainCalculations

700x23 Race

Wheel

700x23 Race

Wheel

2" Mid Drive Pulley

2" Mid Drive Pulley

53 Tooth Chain Ring53 Tooth

Chain Ring

INPUT3" Pulley w/

Cranks

INPUT3" Pulley w/

Cranks

BeltBelt Bike ChainBike Chain

700x23 Race

Wheel

700x23 Race

Wheel

Cassette34-21-17-15-13-11-9T

Cassette34-21-17-15-13-11-9T

INPUT3" Pulley w/

Cranks

INPUT3" Pulley w/

Cranks

BeltBelt Bike ChainBike Chain

•Speed calculations using mid-drive and possible cassette option.


This document is controlled information and is only reproducible with permission of

Team HPV9

•Validity testing using standard road bike to ensure accuracy of calculations.

Tests performed on Jimmy’s road bike.

Calculation Validity TESTING 700x23mm Series Wheels

NO MID DRIVEUnit Conversion

12.781

Theoretical Experimental

# of Chain Ring Teeth # of Cassette TeethRatio Cadence (Rpm) Speed (Mph) Speed (Mph) % Diff. (%)

39 15 2.600 44 8.951 9.0 4.907893115

39 23 1.696 75 9.950 10.0 4.961837702

39 23 1.696 95 12.604 12.6 0.381672245

39 23 1.696 115 15.257 15.2 5.725182191

53 23 2.304 75 13.522 13.6 7.768651236

Wheel Dia (in) 26.300

Wheel Rad (in) 13.150

Circumference (in) 82.624

DrivetrainCalculations



•Mock up with 53 tooth chain ring and standard bike cassette/derailleurand belt driven pulleys.

Picture taken on 9/1/2008 in Jimmy’s Garage.

First Mock Up



•Hybrid belt and chain drive system to minimize losses.


First Mock Up



of Team HPV13

Video of First Mock Up



Frame Calculations

New calculations have shown that our previous approach to carbon fiber/nomex frame was a worthy idea, but not to be expanded upon.

Difficulty in manufacturing yielded mixed feelings from within the group.

Torsional rigidity was also shown to be compromised through quick calculations using the following formula:

<<

It can be shown that the parallel axis theorem in our case yields results that are substantially smaller than that of the torsion of a thin walled rod

Wikipedia



of Team HPV15

Frame Design

•Current aluminum frame design undergoing stress analysis.



of Team HPV16

ShellDesigns

CdAof 2.4

CdAof 0.6

CdAof 0.25

http://www.adventuresofgreg.com/HPVlog/VehicleDrags.html



of Team HPV17

Loss System % Total Power Loss

Aerodynamic Drag 85-90%

Rolling Resistance 5-10%

Drivetrain Friction Loss ~1-2%

Wheel Rotation Power ~1%

Miscellaneous Loss

Power to Overcome Gravity (Hill Application)

Varies Greatly Depending on % Grade of Hill

Power Loss for HPV by Percentage.

Shell Considerations



Feasibility Calculations

There were a few significant advancements made over the summer:

• A document was authored explaining the scope, feasibility of the project and the role of team members

• Requests for funding were authored and include 11 different companies

• A Pro|E assembly of Jimmy’s exact dimensions was created for ease of ergonomic design of the frame

• A few members practiced programming in MATLAB, while others have experience in CAM, a MATLAB-like, NASA proprietary software chosen for the ease at which users can add functions



of Team HPV19

•This shows relation between frontal area, Cd, and power required to travel 61.5mph.

ShellFeasability



of Team HPV20

•Power feasibility calculations.•Shows how many watts for how long and energy associated with wattage (log scale).

Power Feasibility



of Team HPV21

•Impulse from the high watts has little effect on overall change in velocity while long, slow burns have a significant change in velocity. This also shows that if vehicle is lighter, it will have greater change in velocity.

Power Feasibility



of Team HPV22

•Shows Kinetic energy associated with different weights and speeds•Will be used for braking distance calculations

Braking Feasability



of Team HPV23

Current Sponsors

At this time, our sponsors are as follow:



of Team HPV24

Current Budget

Total Budget = - $62



of Team HPV25

Timeline

March April May June July Aug Sept Oct Nov Dec Jan Feb March April MayJimmy Conditioning Fundraising

Assemble Sponsorship Package

Brainstorm Potential Businesses

FrameDesign Re-Design

Pro|Engineer Determine Materials Ansys

Manufacture Shell

Design

Pro|Engineer Determine Materials CFD

Manufacture Drivetrain

Design

Manufacture Build Final HPV Test Present Final Results

Team Human Powered Vehicle

Documents

Transcript of Team Human Powered Vehicle