11/23/2010

Preliminary Design Review (PDR)Lunar Wormbot (LW)

Team 1

Team Members:Charles Boyles

Ben GasserJosh Johnson

Ben LongNathan Toy

MAE 490-02: Introduction to Engineering Design- Product RealizationInstructor: Dr. Christina L. Carmen, Ph.D.

Customers:NASANSSTC

Technical Advisors: Mr. Ben DiMieroDr. Jessica GaskinMr. Michael KuhlmanMr. Blaze SandersDr. Michael TinkerMr. Lafe Zabowski

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Overview

• Purpose of the PDR• Mission Statement• Top Level Requirements• Selected Design• Design Drawings• Technical Analysis

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Overview

• Safety Considerations• Material Selection• Cost Analysis• Manufacturing Processes• Problems and Solutions• Activity Plan• Summary

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Purpose

• Establish that the preliminary design meets the technical requirements

• Demonstrate that the design can be produced with acceptable risks

• Establish the operability and producibility of the selected design

• Refine cost and scheduling to ensure that planning, production and testing are feasible

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Mission Statement

Ultimately it is the hope of this team to lead to knowledge enabling a burrowing robot to operate on the lunar surface to gather soil samples. Leading to that goal, and staying within the scope of the time period of this project, a single, prototype LW will be produced for earth based testing. This robot will be considered successful in its mission if it offers the ability to burrow through a fine particulate soil simulant, return testing data leading to improvements in design, and exhibits the robustness necessary for space based soil sampling.

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Top Level Requirements

• Top-level Requirements– Burrowing through fine particulate matter utilizing

peristaltic motion– Prototype built for Earth-based testing– Ability to acquire 50 one gram samples at various

depths– Segment power consumption of 4 Watt maximum

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– Skin material capable of insulating internal electrical and mechanical systems from fine particulate matter

– Space to integrate a sensing and navigation package

– Production of at least 66 N of force directed perpendicular to the segment’s longitudinal axis

Top Level Requirements

Designs Considered

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NASA/NSSTC Initial Concept

Utilizes AX-12 servo motors as well as hinged plates

Designs Considered

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Modified NASA/NSSTC design utilizing linear actuators and hinged plates

Designs Considered

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Linear actuators with pressurized flexible sidewall

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Selected Design

Linear actuators with unpressurized springy sidewall

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Evaluation MatrixBody Evaluation Mandatory

(Y=1/N=0)Weight Scale

AX-12 (Rigid Wall)

Linear Actuators

(Rigid Wall)

Flexible Wall w/

PressurizationSpring Wall

Cost 0 9 4= Least Cost 1=Greatest Cost 2 3 3 4

Movement Simplicity 0 6 4= Simplest 1=Most Complex 1 2 2 4

Flexibility (3-D Mechanical Movement) 0 5 4= Most Flexibility

1=Least Flexibilty 1 1 3 4Regolith Resiliency 1 10 4= Most Resilient

1=Least Resilient 1 1 4 3Skin Complexity 1 10 4= Least Complex

1=Most Complex 3 3 1 2Volume 0 10 4=Smallest Volume

1=Largest Volume 1 1 3 3Weight 0 8 4=Lightest

1=Heaviest 1 2 3 3Technology Readiness 0 4 4=Most Ready

1=Least Ready 4 3 2 2

Power Consumption Less Than 4 W 1 10

4=Lowest Power Consumption

1=Highest Power Consumption

3 4 3 3

Safety 0 4 4=Most Safe 1=Least Safe 1 2 2 4

Critical Failure Modes 0 10 4=Least Susceptible 1=Most Susceptible 1 2 2 3

Utilizes Peristaltic Motion 1 2 4=Most Peristaltic 1=Least Peristaltic 2 2 3 4

Utilizes Consumable Mass 0 54=No Mass

Consumption 1=Large Mass Consumption

4 4 1 4

Recycleable 0 7 4=Most Recycleable 1=Least Recycleable 2 2 1 2

Ease of Maintenance 0 9 4=Easily Serviced 1=Diffi cult Service 1 2 2 3

Score 100.0% 44.5% 56.4% 59.6% 77.3%

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Selected Design

• Advantages of Selected Design• Smaller cross section• Less mass• Relatively low complexity• Allows 3-D motion

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Design DrawingsFirgelli L16 Linear Actuators

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Design DrawingsAluminum bulkhead with 3-bolt pattern

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Design DrawingsWiring bus conduit

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Thermal Analysis

(1) From table 4.1, pg. 209, shape factor for a vertical cylinder in a semi-infinite medium.(2) From table 4.1, pg. 209, heat transfer by conduction using a shape factor.(3) From equation 3.27, pg. 117, heat transfer by radial conduction through a

cylindrical wall.

(1) (2) (3)

Thermal Analysis Basic Equations*

*Fundamentals of Heat and Mass Transfer, 6th Edition, Incropera, DeWitt, Bergman, Lavine

ConcreteLunar

RegolithFiberglass

EpoxyKevlar

Carbon Fiber

0.72 0.015 0.4 1.3 400

Thermal Conductivity in Watts Per Meter Kelvin

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Thermal Analysis

Heat Transfer and Internal Temperature Analysis:Earth Based Testing – Using Dry Concrete Mix and Three Skin Materials:

Fiberglass: 77.4 FKevlar: 79.0 FCarbon Fiber: 77.4 F

Summary: The internal temperature will be approximately 80 degrees Fahrenheit, and the skin materials evaluated show no clear benefits or problems in this testing environment.

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Thermal Analysis

Heat Transfer and Internal Temperature Analysis:Lunar Regolith– Using Lunar Regolith and Three Skin Materials:

Fiberglass: 259.9 FKevlar: 261.5 FCarbon Fiber: 259.8 F

Summary: All skin materials and internal components will be able to withstand such calculated temperatures.

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Force Analysis

• Column Buckling • Superposition

• Point Load• Total force required from

actuators• Power Required

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Force AnalysisSimplified Analysis Method

FE = 0.513 lbf Pcritical=0.673 lbf

NetForce = (FE + Pcritical)NS= 29.8 lbf ≈ 133N

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Technical Analysis

Power Consumption of Actuators:Voltage – 12 VCurrent – 136 mA @ 133 N Output ForcePower Consumption – 4.88Watts > 4 Watts

Life Cycle/Durability of Actuator Analysis:Max Rated Cycles– Firgelli L16 = 20,000 cyclesEstimated Stroke Length – 2 cmBurrow Depth – 15 m

Life of Lunar Wormbot – 13 missions

Summary: Based on the rated life of the actuators, the wormbot will be able to accomplish 13 missions of 15 meter depth (includes return to surface).

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Technical Analysis

Bulkhead Stress (Von Mises) Finite Element Analysis

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Technical Analysis

Bulkhead Deflection Finite Element Analysis

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Safety Considerations• Manufacturing

– Standard Risks• Materials

– Minimal• Storage

– Lifting– Dropping– Mishandling

• Testing– Shock threat– Pinch points– Auger Blades

• Maintenance– Shock threat– Sudden movement

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Hazard Assessment

MIL STD 882B Catastrophic (1) Critical (2) Marginal (3) Negligible (4)

Frequent (1) 1 3 7 13

Probable (2) 2 5 9 16

Occasional (3) 4 6 11 18

Remote (4) 8 10 14 19

Improbable (5) 12 15 17 20

Operation HazardsFailure Mode Danger Level Probability Hazard Level Mitigation

Accidental Drop 2 2 2 Designated Hand Holds - Case

Unintentional Power Loss 4 4 19 Redundant Connections – Handling Standards

Simulant Penetration 4 2 16 Seal the design

Pinch Hazard 3 2 9 Warning Stickers

Unintentional Power on 3 4 14 Lock Out/tag out Procedure

Battery Corrosion 2 5 17 Scheduled Maintenance

Military Risk-Hazard Assessment Standard 882B

Failure Modes

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Material Selection

• Bulk heads– Aluminum 7075– Titanium– Steel

• Skin– Fiberglass– Kevlar– Carbon Fiber

• Actuators– Firgelli L16

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Manufacturing Processes

• Facility Requirements• Auger

– Rapid Prototyping– 5-axis Machining

• Segments– Standard Machine

Shop– CNC Capabilities

• Locations– W100 Technology

hall• $0 /hr labor

– NSSTC Machine Shop• $60/hr Labor

• Duration– 2-3 months

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Item Vendor Part # Cost/unit Qty. Total Team CostActive Segments:7075 AL Plate .25"X12"x36" onlinemetals.com $159.43 1 $159.43 $159.43Flange Button Socket Cap Screws - Stainless #10-24x3/8" Pack of 25 McMaster-Carr 97654A141 $9.25 2 $18.50 $18.50Fiberglass(4oz E Glass) uscomposites.com FG-C0450 $5.15 4 $20.60 $20.60Epoxy resin uscomposites.com EPOX-6355563 $38.50 1 $38.50 $38.50Convoluted (Spiral)- Flexible White Tubing Made with Teflon® PTFE McMaster-Carr 51155K271 $30.17 8 $241.36 $241.36Low Pressure Spring Hose Clamps 1.125" (pack of 25) McMaster-Carr 5324K23 $5.09 1 $5.09 $5.09Latex Coating - 32 oz. liquidlatex.com 912 $23.39 1 $23.39 $23.39Auger Head:Auger (Rapid Prototype) $600.00 1 $600.00 $600.00Other:Shipping (estimated @ 10% of items) $110.69 $110.69

Total $1,217.56 $1,217.56

Segment Parts and Hardware

Cost Analysis

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Cost Analysis

Item Vendor Part# Cost/unit Qty. Total Team CostL16-P Linear Actuator firgelli.com $80.00 26 $2,080.00 $2,080.00The MiniBoardPro expresspcb.com $75.00 4 $300.00 $300.00Arduino Mega sparkfun.com DEV-09152 $50.00 2 $100.00 $0.00Propeller Microcontroller Digikey.com P8X32A-Q44 $7.99 8 $63.92 $63.92Full H-Bridge Gate Driver Digikey.com Digikey 497-1396-5-ND $5.83 16 $93.28 $93.28Analog to Digital Convertor Digikey.com Digikey ADC0834CCWM-ND $3.33 8 $26.64 $26.641.23 – 29 V Adjustable Voltage Regulator Digikey.com Digikey LP2952AIM-ND $4.26 8 $34.08 $34.08Molex Board to Wire Connector Digikey.com Digikey WM7648CT-ND $0.86 24 $20.64 $20.64X1 - 5MHz Crystal Digikey.com Digikey 300-8347-1-ND $0.90 8 $7.20 $7.2012V Power Supply Digikey.com Digikey 945-1076-ND $27.17 1 $27.17 $27.17Solder Paste Pololu $24.00 2 $48.00 $48.00 Stencil Pololu $32.00 1 $32.00 $32.00Brushless DC Motor $159.60 1 $159.60 $159.60Motor Controller $109.00 1 $109.00 $109.00Shipping (estimated at 10% of items) $310.15 $310.15

Total $3,411.68 $3,311.68

Electronics

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Item Vendor Part # Cost/unit Qty. Total Team CostMachinist's Time ($/hr) NSSTC Bulkhead x10 $60.00 15 $900.00 $0.00Layup of Fiberglass ($/hr) $30.00 10 $300.00 $0.00Assembly ($/hr) $30.00 10 $300.00 $0.001/2" End Mill - Aluminum Cutting MSC Direct MSC #: 97651749 $40.64 2 $81.28 $81.28Hand Tap - Tapered #10-24 MSC Direct MSC #: 74328261 $6.16 3 $18.48 $18.48Shipping & Handling MSC Direct $20.00 1 $20.00 $20.00

$1,619.76 $119.76Total

Cost Analysis

Manufacturing Cost

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Vendor Part # Cost/unit Qty. Total Team Cost$15.00 1 $15.00 $15.00$10.00 1 $10.00 $10.00$50.00 1 $50.00 $50.00$50.00 1 $50.00 $50.00$100.00 1 $100.00 $100.00

6" OD x 5 3/4" ID Acrylic Tubing ($/ft) usplastic.com 44550 $10.48 6 $62.88 $62.88Travel to Kennedy Space Center (KSC)

Roundtrip Flight- Huntsville,AL to Orlando,FL $250.00 3 $750.00 $750.00Hotel ($/night) *estimated $100.00 8 $800.00 $800.00

$1,837.88 $1,837.88Total

Test (Associated Materials)Test 1: Material Validation Test (Support jig)Test 2: Electronics Functionality Test (Wire, computer setup)Test 3: Force Testing (strain gages, force sensors, holding jigs, etc.)Test 4: System and Controls Test (Holding Jigs, Faro Arm, Measuring equipment)Test 5: Multi-Segment/Peristaltic Motion Verification (Wiring bus, Jigs, Sandbox)

Cost Analysis

Testing Cost

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Total Team CostTable 4.1.1: Segment Parts and Hardware $1,217.56 $1,217.56Table 4.1.2: Electronics $3,411.68 $3,311.68Table 4.2.1: Manufacturing Cost $1,619.76 $119.76Table 4.3.1: Testing Cost $1,837.88 $1,837.88

$8,086.88 $6,486.88Total

Item

Cost Analysis

Summary of Cost Analysis

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Problems and Solutions

• Resurfacing– Aft end equipped with auger

• Power Consumption– Batteries or capacitors

• Actuator limitation– Custom design

• Parts Procurement– Local suppliers

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Future Work

• Analysis of sidewall members• Actuator efficiency• Collaboration with LA Tech concerning

system integration• Manufacturing prototype• Testing sub-systems

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Activity PlanTask Name

Lunar WormbotDocumentation

CDD Draft

SRR Presentation

CDD Final

CDR Presentation

Product Design Specif ications

Preliminary Design Analysis Report

PDR Presentation

Final Design Reports

Manufacturing Processes

Fabrication Reports

Design AnalysisThermal Analysis

Stress Analysis

Force Analysis

Life-cycle

X-TOOLSSConceptual Design and Parameters

Critical Parameters

Optimization Routine and Code

Run X-TOOLSS and Refine Routine

CADConceptual Design

Preliminary Design

Final CAD Design

Manufacturing ProcessesPrice Estimates

Order Parts

Manufacture

General ResearchPatent Research

Existing Products

Activity PlanTasks

Scheduling

Josh JohnsonJosh Johnson

Josh JohnsonJosh Johnson

Josh JohnsonJosh JohnsonJosh JohnsonJosh Johnson

Josh JohnsonJosh Johnson

Ben LongCharles BoylesNathan ToyBen Gasser

Ben GasserBen Gasser

Ben GasserBen Gasser

Charles BoylesCharles Boyles

Charles Boyles

Charles BoylesCharles Boyles

Charles Boyles

Nathan Toy,Ben LongNathan Toy,Ben Long

Ben LongBen Long

15 18 21 24 27 30 2 5 8 11 14 17 20 23 26 29 2 5 8 11 14 17 20 23 26 29 1 4 7 10 13 16 19 22 25 28 1 4 7August 2010 September 2010 October 2010 November 2010 December 2010

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Summary

• Selected Design• Size• Aesthetics• Functionality• Performance• Reliability

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Summary

•Technical Analysis• Thermal properties• Stress analysis• Force analysis• Life-cycle analysis

• Cost Analysis• Materials utilized• Manufacturing• Overhead

• Future Work

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References

• Software Packages• Solid Edge ST and v20• SolidWorks • X-TOOLSS and MS Visual Studio• Mathcad v14• MS Excel • MS Project

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References

• Books• Incropera, DeWitt, Bergman, Lavine,

“Fundamentals of Heat and Mass Transfer 6th Edition”

• Juvinall, Marshek, “Fundamentals of Machine Component Design 4th Edition ”

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Acknowledgements

• Adam Burt• Kirk Biszick• Dr. Christina Carmen• Steve Collins• Ben DiMiero• Dr. Jessica Gaskin

• Michael Kuhlman• Blaze Sanders• Dr. Michael Tinker• Lafe Zabowski• Dr. Francis Wessling

11/23/2010

Questions

Hail Mary Plan