dasm2_cdrpresentation_12feb16 (3)

© 2012 Boise State University 1

DASM2- Critical Design Review

Ammar Alobithani, Cody Breckenridge, Raymond Clark, Derrick Hirsch,

Lauren Johnson, Van Jones, Evan Mayfield, Dustin Miller, and Michael Wolf


Background, Needs & Specs

Ammar Alobithani


Project Background— Data Athletics is a company that specializes in developing

equipment to help athletes train at higher levels

— The Speed Machine is designed to help athletes move faster by

pulling them 110% of their unassisted top speed

— The ideal solution will reconfigure the motor controller and

redesign the external frame to allow the athlete to run toward

and past the machine


Objectives— Enhance teamwork skills by communicating, collaborating, and

excelling as an interdisciplinary group— Establish professional relationships with our professors and

sponsors— Meet the engineering needs of our sponsors — Design, analyze, and test each subsystem of the Speed

Machine to ensure the integration of the final Speed Machine works properly

— Integrate the electrical and mechanical designs into one working machine


Customer Requirements / “Needs”

— Must be capable of pulling a runner faster than their

natural/unassisted top speed

— Device will be operable via a Bluetooth device and app

— Device will utilize robust frame to house all sub-systems

— Device will be operable by one person


Engineering Requirements / “Specs”

— Must be capable of pulling runners for a minimum of 10

seconds at 110% of their unassisted top speed

— Must contain quick-release mechanism

— Device will utilize system to evenly wind cable on spool

— Device will have built in safety stop if pulling force exceeds

expected amount


Mechanical Design, Analysisand Testing Plans


Motor & Power Transmission

Michael Wolf


Power Transmission System


Drive Transmission

V Belt Configuration

25in 2L Rubber Belt

155/205˚ Contact Angle

Pulley Pitch DiametersPd1 = 1.9in Pd2 = 4.9in

Speed Reduction


Motor

Turnigy G60 Brushless Outrunner Motor

Turnigy G60 Brushless Outrunner Motor• Economical• Slow angular velocities• Compact/lightweight

Specifications: Speed------------------------300 RPM per voltPower------------------------1425W max Weight-----------------------360g (0.8lb)

Speed Calculation:18.5V battery * 300kV = 5550 RPM


Motor Mounting

Fully Supported Shaft

Sliding Lock Slots

Belt Pre-Tension = 17 lbs


Speed Reduction

Motor Max Speed = 5500 RPM

With

Max Reel Speed () = 2150 RPM

Rope Linear Velocity

Assumed Average Spool Radius () = 2 in = 0.0508 m

Maximum Rope Linear Velocity () = 11.5 m/s


Rope Management

Evan Mayfield


Servo-arm oscillator

Isometric view of servo motor with arm Frontal view of design



Right view of power transmission and rope management module.

Top view



Specifications: Speed------------------------0.13 sec/60 @ 7.4V Torque-----------------------111 oz-in @ 7.4V Weight-----------------------59 g (0.14 lbs)

Savox SW-0230MG Waterproof Servo



Top view of servo in assembly

35°


Arm

Van Jones


Rear Arm Attachment and Telescoping Shaft

Rear Arm Attachment Telescoping Shaft


Arm Attachment with Full Assembly


Arm Attachment with Full Assembly - Closed


Utilizing Telescoping Shaft



View of runner running towards SM


Pulley System

Side View


Pulley System

Top View


Pulley System

Bottom of Arm Top of Arm


Arm Design Analysis• Points of Interest

– Base of Arm

– Hinges

– Arm Base Lockpin


Stress Calculation in Arm

Arm cross-section (inches)

𝐼𝑍=𝐼 𝑦=2.94 𝑖𝑛4

Max dimensions of arm (inches)


y

z

F

Tz

Ty

𝑀𝑧=𝑀𝑦=0𝑇𝑧=𝐹∗𝐿𝑦≈24 𝑙𝑏𝑖𝑛𝑇𝑦=𝐹∗𝐿𝑧 ≈500 𝑙𝑏𝑖𝑛

σ 𝑧=𝑇𝑦 ∗𝑟𝐼𝑧 =𝟏𝟐𝐩𝐬𝐢

σ 𝑦=𝑇𝑧∗𝑟𝐼𝑦 =𝟐𝟓𝟓𝐩𝐬𝐢


Testing Plans for Arm• Test arm strength with maximum expected

tension

• Test arm stability with runner attached

• Test rope for smooth feeding through pulley system


Electrical Design, Analysis and Testing PlansCody Breckenridge


Speed Machine System Diagram


Prototype Shield Stack DesignArduino Mega 2560

• Based on the ATmega2560 AVR microcontroller

• 70 digital I/O pins• 15 of which can be used as PWM• 16 can be used for analog• Several options for communication

protocols• Has an extensive support network for

embedded projects• This development board will control

all aspects of signal processing and calculations


Prototype Shield Stack DesignArduino MicroSD Shield

• Easily interfaced with Arduino board• Increased memory for overall design


Prototype Shield Stack DesignLoad Cell Shield (Price: $19.95)

• Based on AD8426 Amplifier• Adjustable areas

• Potentiometer adjustable Voltage Reference

• 0 to 60 dB of gain• Second Order Bessel Low Pass Filter

• Frequency cutoff adjusted by changing resistors and capacitors


Prototype Shield Stack DesignArduino Prototype Shield (Price: $4 - $10)

• 1.0 Arduino pinout• 1 Reset button• 1 ICSP connector• 14 pin SMD footprint (50 mils pitch)• 20 pin Through Hole footprint (100 mils pitch)

1.4 cm X 2.2 cm1.6 cm X 4 cm


Prototype Shield Stack DesignBenefits of using the shield:

• Avoid inherent set backs of creating a custom PCB• Improved electrical prototype layout• Less wiring • Cheap product (rang of $4 to $20)


Load Cell DesignLoad Cell : FC2211-0000-0025-L (Price: $60. 96)

• Type: Compression• Accuracy : 1%• Operating force: 25lbs• Excitation Voltage: 5V• Height: 19.4mm• Width: 34mm


Load Cell DesignFX1900-0000-0025-L (Price: $30.76)

• Operating Force: 25lbs• ExcitationVoltage: 5V


Load Cell DesignLoad Cell Shield, Instrument Amplifier (AD8426)

• Bandwidth (G = 1): 1 MHz • CMRR (G = 1): 80 dB • minimum Input noise: 24 nV/√Hz• Gain range: (1 - 1000 V/V)/(0 – 60 dB)• 2 channels in a small, 4 mm × 4 mm LFCSP• 2.2 V to 36 V for single supply• operates on supplies ranging from ±1.35 V to

±18 V for dual supplies


Load Cell DesignLoad Cell Calculations

Rated output (Rout) = 20mV/VExcitation voltage (Ev) = 5VMax output (Vmax_out) = Rout*Ev = 100mVAmplified output = G*Vmax_outAD8426 transfer function: Vout = G*(Vout+ - Vout-) + VrefUsing 0-5 V and Vref = 2.5V 5V = G*(100mV) + 2.5VTherefore: G = 25V/V = 27.96dB

Results: 10mV – 100mV load cell output voltage is amplified to 2.75V-5V for ADC processingLoad cell will require calibration to determine zero force voltage and max force voltage for programming purposes

10 bit ADC 1024 possible valuesAmplified Load cell resolution 5V/1024 = 4.88mV

Therefore: a 0.0244 change in pounds will result in a 4.88mV change in amplified voltage if hysteresis non-linearity is neglected


Load Cell Design


Motor Controller Design


Motor Controller DesignComparisons TURNIGY TRUST 70A MambaMaxPro

Max motor current of 60A X X

Output voltage of 18.5V X X

Can use with brushless and brushed motors

X X

Need to program it through SD card or a kit

X X

Can program it in Ardiuno X X

Requires purchase of programming card

X X

Needs to be purchased X

Price + programming card $32 + $3 $127 + $22


Motor Controller Design


MotorsME suggestion (cost around $54):

Turnigy G60 Brushless Outrunner 300kv (.60 Glow) specification:• Battery: 5~7 Cell /18.5~25.9V• RPM: 300kv• Max current: 60A • No load current: 11V/1.2A• Current capacity: 60A/15sec• Internal resistance: 0.04 ohm• Weight: 360g (not including connectors)• Diameter of shaft: 6mm• Dimensions: 81x50mm


Software Design (Android)


Software Design (Arduino)• Use extensive Arduino libraries to assist with

programming• Fix memory allocation issues (done)• Redesign of code is possible if performance issues are

encountered• Test software on actual devices • Modify code when necessary• Use software as part of testing for the devices it controls


Testing Plan— Over-Speed and Single User— Power Supply Compatibility — Force Control/Noise — Run Completion/ Run Failure — Storing and Tracking Data — Weather Resistance

— Wireless Digital Interface— Passing Electrical Code— Device Measurements — Battery Endurance — Budget and Manufacturing — Facility Surface — Distance Measurement


Budget, Schedule & Project Risk Assessment

Ray Clark


BudgetAssembly/Category Estimated Costs Description/Comments

Arm System $150.00• Estimation based off of all new components• Components from previous Speed Machine will

be used if adequate.

EE Design $205.41• Total price for the load cell, load cell shield, and

Arduino proto shield.• Price also includes shipping and handling

Frame $xx.xx • Already built before the project was started.

Motor $92.73• Motor and connected components have been

selected.• Price includes shipping and handling.

Power Transmission $158.05 • All parts for this assembly have been selected.• Price includes shipping and handling.


Assembly/Category Estimated Costs Description/Comments

Rope Management $170.00• Estimation based off of all new components• Components from previous Speed Machine will

be used if adequate.

Misc. $100.00 • Price includes unforeseen needs or if components are damaged.

Total $926.19


Schedule


Project Risk AssessmentPossible Problems Estimated Likelihood Contingency Plan

Integrating each subsystems into one system that will fit

inside the current casingModerate

Team chief will check off the dimensions as they are designed, and the team members responsible for the subsystem can create cardboard prototypes to place

in the casing to mark off the required space for his/her subsystem

Mounting the subsystems to one block Low Create 3D model in SolidWorks to visualize the best

way to mount each subsystem to one block

Manufacturing will take our team members more time than expected to complete

Moderate Outsource some parts to a machine shop that can get a project done more quickly

Material lead time issues Low Source material from multiple locations, and keep track of shipping


Possible Problems Estimated Likelihood Contingency Plan

Meeting the deadlines of major milestones Low

Utilize liquid planner, weekly project updates to professors, and complete individual responsibilities

on time

Problems with running software Low/Moderate Seek advice of faculty/students/online resources

Noise contamination of signal integrity cannot be reconciled Moderate Consider a second 9V supply to power sub-circuitry

Burn-out/Destroy Electrical Low/Moderate Check the Re-usium in Boise for electrical components for quick replacement

Meeting the time line for a working prototype Moderate Seek advice of faculty and re-evaluate the schedule


THANK YOU

Ammar Alobithani, Cody Breckenridge, Raymond Clark,Derrick Hirsch, Lauren Johnson, Van Jones, Evan Mayfield, Dustin Miller, and Michael Wolf

dasm2_cdrpresentation_12feb16 (3)

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