final report - boeing 4

7/30/2019 Final Report - Boeing 4

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EDSGN497D Senior Multidisciplinary Capstone Project: Development of an Automated

Helicopter Rotor Wake Survey System Sponsored by The Boeing Company

Design Specifications Report

21 March 2013

Team Name:

WhirlyBirds

Team Members:

Bill Boggs

Steven Drew

Ryan Hammerschmitt

Scott Hromisin

Joseph Oberholtzer

Dylan Wynn

NoIntellectual Property Rights Agreement

No Non-Disclosure Agreement

Executive Summary:


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The objective of this project is to measure the rotor wake of a helicopter below the rotor

at a minimum of eight azimuthal angles, three heights and five radial positions. The local

pressures will be measured using a pressure probe and then passed to a computer for data

reduction and visual representation. It is essential that the pressure probe never touches the rotor

blade in order to avoid risk of injury. The Boeing Company is supplying a stand, a drive system

with a rotor and a test probe for testing the pressure change under the rotor. The rotor is six feet

in diameter and is run by a 1.5 horsepower motor. The design process began with a Gantt chart

to plan out the timetable of the project. The Gantt chart is essential to project planning because it

sets deadlines for different aspects of the system. The Gantt charts first section is the research

and brainstorming stage, which defines the path in which the project will go.

Many different possible solutions to the problem have been brainstormed, analyzed and

rated to see which design will provide the most overall efficiency. After the analysis, the best

design is selected and a CAD model is created, for every different theater of the system. This

includes the azimuthal design, which moves the pressure probe stand a full 360 degrees in orderto measure any point around the test stand. The radial system is designed to move to any radial

position under the rotor and the vertical system will move the pressure probe in the y direction.

After CAD model creation and construction, the initial design undergoes extensive testing.

Software is also tested to make sure that the signals sent to the system for motor movement are

accurate. Three stepper motors move the system to the coordinates specified by the user of the

software, so software testing and mechanical testing are done in conjunction to fully verify the

accuracy of measurement. Tests are done to make sure the pressure probe is reading accurate

pressures following verification of the accuracy of the mechanical system. After the testing

analysis and second design is constructed, correcting the mistakes that were seen in the first

design. Currently the team is under budget and on schedule to test the second design iteration.

To validate the capabilities of the system, individual components were tested as they

were constructed and finally the whole system was tested. The modular design allowed discrete

testing of the mechanical motion systems. Testing of the sensing capabilities was performed with

a manometer and then in the Penn State wind tunnel. Finally real world testing with a rotor test

stand was used to evaluate the entire system performance. The system ultimately proved its

ability to meet and exceed customer needs. With the customer needs met, additional design

iterations should be used to refine the design for manufacturing and ease of use.


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Table of Contents

Table of Contents ............................................................................................................................ 3

1. Introduction ............................................................................................................................. 4

2. Customer Needs Assessment ................................................................................................... 4

3. External Search ........................................................................................................................ 7

4. Engineering Specifications .................................................................................................... 11

5. Concept Generation and Selection ........................................................................................ 16

6. System-Level Design ............................................................................................................ 24

7. Special Topics ....................................................................................................................... 25

8. Changes to the Statement of work ......................................................................................... 36

9. Final Discussion .................................................................................................................... 69

10. Conclusions and Recommendations ...................................................................................... 7611. References ............................................................................................................................. 80

12. Appendix A: Survey For Analytical Hierarchy Process ....................................................... 81

13. Appendix B: External Search URLs .................................................................................... 83

14. Appendix C: Concept Generation ......................................................................................... 84

15. Appendix D: Concept Generation ......................................................................................... 88

16. Appendix E: Resumes ........................................................................................................... 90

17. Appendix F: Changes To The Statement Of Work ............................................................... 91

18. Appendix G: Calculations for Design Analysis .................................................................... 98

19. Appendix H: Shop Drawings .............................................................................................. 114

20. Appendix I: Bill Of Materials ............................................................................................. 120


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Introduction1.

Testing of model helicopter rotor systems typically consists of measuring loads on the rotors to

determine the aerodynamic effects of speed, angle of attack, and blade shape. Current testing methods,

however, have no way of measuring what is happening below the rotors. Measuring and analysing theflow properties beneath the rotor could provide researchers with beneficial information regarding the

performance of the rotor.

1.1. Initial Problem StatementBoeing has challenged our team with designing, building, and testing an

apparatus to position a pressure probe at any point in 3D space below a rotor test

stand. The testing apparatus to be designed will allow valuable information to be

collected about the properties of a helicopter downwash.

1.2. ObjectivesThe system must be able to take an input from a user, specifying the location at which the

measurements are to be taken. The apparatus must then move the probe to the desired location.

The system to be designed will be motorized and fully automatic, being able to move to the

positions specified by the user with no additional human interaction. Pressure readings will be

taken using a pitot-static probe with a pressure transducer, and these readings will be transmitted

to a computer. The computer will reduce the data and plot the results in three dimensions. The

team will deliver the designed mechanism, all relevant drawings and CAD files, data reduction

and plotting software, and instructions for use.

Customer Needs Assessment2.

2.1. Gathering Customer Input

We will be able to determine our customer needs through weekly interactions with our

client. Via weekly conference call, we will be able to assess the customer needs by asking

questions. The first few conference calls will be dedicated developing a complete understanding

of our customers wants and needs. Boeings most basic needs are listed clearly in the project

statement on the Penn State Learning Factorys website. Using these most basic needs as a

springboard, the team was able to generate a long list of questions for our project sponsors in

order to more truly understand their needs. During the first conference call on January 29th, 2013

the team received objective answers to each and every one of the questions. Through thequestions a list of formal customer needs could be developed.


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The Boeing Company Customer Needs

1. The pressure sensor has multiple positions

2. The pressure sensor is accurately positioned

3. The pressure sensor is positioned in the rotor wake

4. The pressure sensor position can be changed remotely

5.

The pressure sensor reads any pressure in the rotor wake

6. The pressure data captures the constantly varying pressure

7. The pressure data is accurate

8. The angular velocity of the rotor is collected

9. The system includes data visualization software

10.The system includes sensor control software

11.The system must include an instruction manual

12.The system must be reliable

All pertinent customer statements are recorded by several team members in notebooks during conference

calls. Not only does this give us a level of redundancy but it also helps to avoid misinterpreting customer statementsbecause we compare our notes after every call-in. As many of the statements are quantitative answers to ourquestions, developing customer needs and design metrics is very straightforward. Any new statements by thecustomerat this point will be assumed to be wants and not exactly needs unless they tell us otherwise. This willensure that as our target design criteria remain constant as product design, building, and testing begins in theupcoming weeks.

2.2. Weighting of Customer NeedsTo ensure that our sponsors needs were being properly considered, a moderate length

survey was sent to them. The survey compares every need against every other need on a 5-3-1-3-

5 scale. For example:

Need A 5 3 1 3 5 Need B

Selecting 1 means needs A and B are of equal importance. The values of 3 and 5 on the left

correspond to Need A being of higher importance than Need B, and vice versa. The results of

this survey may be found in Appendix A: Survey For Analytical Hierarchy Process.

The results of this survey could be directly inputted into a hierarchical list of customer

needs (AHP) matrix. This matrix calculates the relative importance each customer need with

respect to every other customer need. Development of this matrix is discussed in great detail in

Ulrich & Eppinger. Our AHP matrix may be found in Table 1.


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Table 1. AHP Matrix of Customer Needs to Determine Weighting for Customer Needs

Simplicity

Accura

cy

Cost

Durabi

lity

Easeof

building

Easeof

implem

entation

Versatilityof

components

Timetobuild

Aesthetics

SumWeight

Rounded

Simplicity 1.00 0.33 1.00 1.00 1.00 0.33 1.00 0.33 5.00

11.0

0

0.08

2 0.08

Accuracy 3.00 1.00 3.00 3.00 3.00 3.00 3.00 3.00 5.00

27.0

0

0.20

3 0.20

Cost 1.00 0.33 1.00 0.33 0.33 0.20 0.33 0.33 1.00 4.87

0.03

6 0.04

Durability 1.00 0.33 3.00 1.00 1.00 0.33 1.00 3.00 5.00

15.6

7

0.11

8 0.12Ease of

building 1.00 0.33 3.00 1.00 1.00 0.33 1.00 0.33 5.00

13.0

0

0.09

7 0.10

Ease of

implementatio

n 3.00 0.33 5.00 3.00 3.00 1.00 3.00 3.00 5.00

26.3

3

0.19

8 0.20

Versatility of

components 1.00 0.33 3.00 1.00 1.00 0.33 1.00 1.00 5.00

13.6

7

0.10

2 0.10

Time to build 3.00 0.33 3.00 0.33 1.00 0.33 1.00 1.00 5.00

15.0

0

0.11

3 0.11

Aesthetics 0.20 0.20 1.00 0.20 3.00 0.20 0.20 0.20 1.00 6.20

0.04

6 0.05

Total 132 1

Definitions for the customer needs can be found in Appendix A: Survey For Analytical

Hierarchy Processproceeding the answered customer survey. The results of this AHP matrix

show that positional accuracy and ease of implementation are the most important criteria,

whereas aesthetics and cost are relatively unimportant. The results of this AHP, while helpful in

most regards, are somewhat dubious. Our project sponsors completed the survey which fed

directly into this matrix. They work for Boeing, a billion dollar company, so for them, cost isvirtually a nonissue. However, our team is working on a very limited budget of $1000. For us,

cost has a lot of weight. We may design a state-of-the-art system, but if we can only afford two

parts for it, our design will be no good. We need to make sure that what we design not only

meets their most important needs but also does not exceed out budget.


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External Search3.An extensive external search is being carried out by all members of the group. We need

to see what sort of prior art is already out there, that is, on the market or patented. Given our

budget of $1000, we also had to understand typical traversing and data acquisition (DAQ)

capabilities as a function of cost. The final results of the external search follow.

3.1. Patent SearchThe first level of searching includes researching patents relevant to our product. It is

imperative so understand what is patented so that the final product does not infringe upon the

rights of another individual or company.

Table 2. Results of the Team Patent Search for Existing Prior Art

Patent Name Patent

Number

Filing Date

High speed digital radiographic inspection of aircraft fuselages 6466643 Aug 22, 2000

Method of testing for fuselage cracks 4976136 Oct 13, 1989

Flight air data measuring system 8256284 Aug 22, 2006

Air data system and method for rotary aircraft 7284420 Jul 13, 2004

Static pressure calculation from dynamic pressure for rotary air-

data system and methodology therefor

6938472 Dec 10, 2003

3.2. Existing ProductsThe second part of the search involves documenting what kinds of products are on the

market. Understanding what products are out there, and their costs and capabilities, will help

give the team a good understanding of performance as a function of cost. Knowing this

relationship assists the team in setting acceptable performance goals within the given budget.

Table 3. Existing Traversing Systems, Controls, and Other Related Products Currently on

the Market

Product Description Price *URL

Helicopter Air

Data System

- Measures airspeed across the complete

flight envelope.

- Swiveling pitot probe

Professional/Militar

y grade (i.e. very

high)

1


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- Flow angles

- Air temperature

Curved Rail

Sliders

- Three cam roller bearings per slider

assembly - preload adjustable

$78 - $101 2

Curved Rail

System

- Arc length 180 degrees

- 0.5m1.25m radius

- 1.57m3.927m rail length

- Holes for mounting

$360 - $890 3

Telescoping

Pitot Probe

- Extends from 8in to 38in $305 4

USB to I2C

Converter

-Support the dual interface: I2C interface and

Serial interface.

- Standard 100Kbps and Fast 400Kbps I2C

interface.

- 8 Bit Data Port.

- Data Port pins may be individually selected

to be digital input / output, analog input or

PWM

output.

- 10 Bit ADC, up to 5 analog inputs

$15 5

Low-Cost

Dataq Start

Kit

- 13 bit

- 4 channel

- USB output for Windows XP and higher

- 10000Hz sampling rate max

$150 6

Teensy -

USB-basedmicrocontrolle

r development

system

- USB-based microcontroller development

system Processor

- Flash Memory: 131072

- Analog in: 12

- I/O: 34, 3.3 Volt

$16 - $24 7


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Stepper

Motors

- 200 steps/revolution

- Current: 280mA1200mA

- Voltage: 2.7V10V

- Torque: 180 g-cm - 3.17 kg-cm

$13 - $20 8

Geared

Bipolar

Stepper Motor

-Gear Ratio: 26.85:1

- Gearbox rated for sustained torque of 30

kg-cm

- Maximum speed of 22 RPM @ 12V (with

1063 motor controller)

$39 9

Stepper Motor

Driver

- Circuit board to control stepper motors $10 - $20 10

Velmex

Traversing

Stages

- Precision linear traversing stages

- Manual or motor-driven options

- Screw drive, free sliders, and rotational

Manual: $160 - $

800

Motor: $360 -

$3400

11

3.3. Hobby Projects and Open-Source ProductsSome of the most intriguing results from the external search are the capabilities of many do-it-

yourself projects. Using simple and relatively inexpensive supplies, some people were able tomake novel traversing and DAQ systems.


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Table 4. Do-It-Yourself (DIY) and Open-Source Products / Systems

Project Description Projected

Cost

*URL

Arudino DAQ controller - 500Hz Sampling Rate

- 10 bit resolution

- 1kHz serial, 25khz-50khz with overclock

and I2C

$20 12

Radial Dolly Track Smooth rolling, easy to build DIY curved

dolly track with plans and instructions

$30 13

Simple Pressure Sensor

Signal Conditioning Circuit

Schematic

Allows interchangeable sensors without a

change in the output voltage

n/a 14

Open Source CNC plans Open source plans for a CNC machine

well controlled machine automated

movement

free 15-16

Horizontal/Radial DIY slider Simple, cheap, easy-to-build camera slider

that can be modified for automated

movement

$15 17

* Corresponding URLs may found at the end of this paper inAppendix B:

The external search is proving to be quite fruitful. The team has discovered a diverse

array of products. There are many existing products for straight-line motion, as it is a widely

used feature in many data-collection scenarios such as flaw detection in a part. Linear motion can

be as inexpensive as $20 for some sliders or upwards of $3400 for higher end, motorized

systems. For azimuthal motion (that is not a small, rotating disk), there are significantly fewer

products on the market. Those products that do exist can cost upwards of $400. That is outside

the price range for any single product given the $1000 budget.

In terms of capability per unit dollar, the most intriguing products appear to be do-it-

yourself slider systems for cameras. The slider systems can move smoothly in linear or

circumferential directions. Moreover, the parts to build these systems can be bought at local

hardware stores for a few dollars. As testament to this, the team has already built a first-

generation prototype using all store-bought hardware. The prototype moves in all three

cylindrical dimensions and only cost $50 to make.


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While many existing products and patents have already been found, the external search is

still ongoing. Most of the benchmarking up to this point has focused on physically large portions

of the system i.e. azimuthal, radial, and traversing systems. Much research is now going into the

details of the motion that is, controllers and motors.

Engineering Specifications4.

4.1. Establishing Target SpecificationsWith a strong understanding of the customer needs and the relevant existing technologies, design

metrics will be used as the known parameters of the detailed design. Metrics provide well

defined criteria by which existing solutions can be benchmarked and the success of the solution

can be quantified. The metrics are developed from the customer needs and specifications

established through additional communication with the customer. Meeting all of design metrics

exactly is ideal. However, due to time and budget constraints, along with performance issues,

may make reaching all of metric values impossible. Therefore, it is wise to develop a range ofvalues our system must perform between; that is, a high and a low, or an ideal and minimally

acceptable (metric) value. Most of the acceptable and ideal product specifications were

determined primarily through communication with the customer. Other specifications required

additional research and analysis such as the sampling rates, sampling resolution and frequency

analysis.

Table 5. Acceptable and Ideal Values for System Metrics

Metric

Acceptable

Value Ideal Value

Pressure Sensor Manipulation

Radial Sensor Positions - Quantity 5 >50

Radial Sensor Positions - Accuracy +/- 0.05 +/- 0.005

Radial Sensor Positions - Range 6 to 24 6 to 43

Azimuthal Sensor Positions -

Quantity 8 >80

Azimuthal Sensor Positions -

Accuracy +/- 0.05 +/- 0.005

Azimuthal Sensor Positions - Range 0deg to 180deg 0deg to 360deg

Vertical Sensor Positions - Quantity 3 >30


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Vertical Sensor Positions -

Accuracy +/- 0.05 +/- 0.005

Vertical Sensor Positions - Range 12 to 24 6 to 36

Dimensions of AutomatedMovement 0 3

Pressure Sensor Performance

Pressure Sensor Range 0 psi to 2.5 psi 0 psi to 2.5 psi

Pressure Sample Resolution

10 Bit (0.0024

psi) 13 Bit (0.00031 psi)

Pressure Sampling Rate 160 Hz 2000 Hz

Pressure Sensor Flow Alignment +/- 15 degrees +/- 5 degrees

Rotor Angular Velocity Sensor Performance

Sampling Rate 80 Hz 400 Hz

Data Reduction and User Interface Software

Pressure on 3D Plot Included Included

Sensor Positioning Software User input for

each positionchange

User defined test

sequences

Frequency Analysis Not Included Included

Instruction manual

Positioning mechanism Procedure Procedure,

Replacement Part

Construction,

Troubleshooting

Output Software Procedure Procedure,

Changing/Adding

Code,

Troubleshooting


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Setup of System Procedure Procedure,

Troubleshooting

Duration of System Performance

Hours of Testing 3 Hours >9 hours

4.2. Relating Specifications to Customer NeedsWhile developing an AHP matrix and a list of product metrics are worthwhile and even

necessary practices, the product design process will all be for naught if the finish product does

not meet a customer need. In the ideal case outlined in Ulrich & Eppinger, there will be one

metric that corresponds to each customer need and satisfies that need. In practice though, this is

not always the case. Due to feasibility issues or complex needs, needs may be met only with the

use of two or three metrics. To keep the needs-metrics relationships organized in a clear and

concise manner a needs-metrics method is used (Table 6). In this method, each row of the matrix

corresponds to a customer need and each column corresponds to a metric. A mark is placed at the

intersection of a need and the metric(s) that satisfies it. If there is a mark in every row then we

can be sure that our list of metrics is broad enough to meet all customer needs. Our needs-metrics

matrix is in Table 6. From it, we found that every row has at least one mark in it. Therefore, we

are confident that we can meet of our sponsors needs if we build a product to meet our current

metrics.


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Table 6. Needs-Metrics Matrix using QFD Method for the Rotor Wake Survey Project

Our customer needs were developed through a survey that was completed by the customer. The information provided by the customer in the survey

was then translated into a set of needs with corresponding metrics.

Customer Needs

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 20

Q

uantity

Q

uantity

Q

uantity

A

ccuracy

A

ccuracy

A

ccuracy

Positions-Range

Positions-Range

Positions-Range

Movement

Range

Resolution

Rate

alignm

enttoflow

Sam

plingrate

Plot

Software

Ins

tructions

Ins

tructions

1Pressure sensor has

multiple positions X X X

2

Pressure sensor is

accurately

positioned X X X

3

Pressure sensor is

positioned in the

wake X X X

4

Sensor position can

be changed

remotely X

5

Sensor reads any

pressure in the

wake X

6

System captures

pressure in real

time X X

7The pressure data

is accurate X

8Angular velocity of X


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the rotor is

collected

9

System includes

data visualization

software X

10

System includes

sensor control

software X

11

Instruction manual

is included X X

12The system must

be reliable X


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Concept Generation and Selection5.

5.1. Problem ClarificationBefore generating concepts for our automated rotor wake surveying system we need to

know, in general, how the system is going to work; what it is going to do. Another way of

putting is to ask ourselves: what are the inputs? What are the outputs? What are the basic steps in

between the two? Best way to answer these questions is visually: with a black-box model

showing system inputs/outputs and the energy flow through the system. A diagram like this

contains invaluable information to assist in brainstorming and system-level design. This is

because the diagram defines what goes into our system, what our system must output to meet

customer needs, and the critical sub-functions in between. It is these sub-functions that we will

have to design, build and interface with each other in order to achieve our target outputs. Our

black box model is shown in Figure 1.All black box functions are enclosed in a dashed box.

The largest black box is that of the system: inputs go in, and the rotor wake data is the output.The smallerblack box is the positioning of the probe step. This reads in the desired position,

goes to it, takes a measurement, and passes the analog data along for processing.

Figure 1. System Level Black Box and Energy Flow Design

The system level design is straightforward from Figure 1. The user input will run through an

encoder, the encoder will instruct the motor create a movement for the probe, which will record

data, and send feedback. Multiple iterations of our project will allow us to fix any flaws in our

prototype design. Each design will be selected through a selection matrix based on customer

needs. The needs will be weighted and applied to our design selection table discussed in Section

5.3.


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5.2. Concept GenerationConcept generation is a very critical stage for our project. If done properly, some very

intriguing design ideas are generated. These ideas propagate on to concept selection and a novel,

working system will be chosen. Concept ideas come from two majors sources: external searches

and internal searches. The teams external search is described in Section 3.0. The team has been

conducting multiple internal searches, i.e. group brainstorming sessions as well. During these

meetings, ideas are bounced back and forth of each other. We consider the pros and cons of

certain designs and list then alongside sketches of the idea. Discussions typically focus on

traversing systems, as this is where we have the most flexibility. However, we also discuss

different motors and software platforms we are considering for the system.

Figure 2. Typical design idea during a brainstorming session

More images from brainstorming sessions may be found in Appendix C:.

Once brainstorming is complete we move on to a more formal concept generation stage. Here

ideas are discussed in more detail. Ideas are more practical and well thought out and the

drawings become more technical. Some results from concept generation meetings are:


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Figure 3. Vertical motion conceptscissor lift system

Figure 4. User Interface ConceptMATLAB control GUI


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Figure 5. Combined motionradial and vertical system

More concept generation results may be found in Appendix D.

5.3. Concept SelectionFollowing the guidelines set forth by Ulrich & Eppinger, our concept selection process

consists of two steps: 1) concept screening and 2) concept scoring. Concept screening is a

qualitative process in which we compare our ideas against a reference product and for a given list

of criteria we decide if our idea is better, equal to, or worse than the reference. For our conceptscreening process, we opted to use existing products as our references. Our concept screening

matrix can be found in Table 7. It can be seen from Table 7 that some concepts are relatively

close in score while some are at the bottom of barrel with a very low score. Any concepts with a

value of -6 or less will not move on to the concept scoring matrix.

The concept scoring matrix is designed to calculate the best concept for each of our five

subsystems: azimuthal motion, radial motion, vertical motion, data acquisition, and software. To

do this, the rows of the matrix are the concepts and the columns are the customer needs

previously discussed in Section 2.2. Moving across the columns, each concept is scored on a

scale of 1-10 on how well it meets that particular customer need, with 10 being extremely well.

The score is then multiplied by the corresponding weight for that need. The weights were

determined using the AHP matrix in Section 2.2. The scores for each column are summed

together. The concept from each of the five subsystems that has the highest total score will be the

concept that gets implemented in our final design. The concept scoring matrix can be found in

Table 8.


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Table 7. Concept Screening Matrix

Selection

Criteria

Concept

RadialMotion

Reference(beltdriverail)

Railscrew

drive

Railrack

andpinion

Railwheeldrive

roomba

Azimutha

l

Camerarailsystem

Rail)

centershaftsupport

turntable

verticaltu

rntable

mechanical

roomba

Vertical

Scissorlift

Reference(Screwlift)

racnpinion

maglev

piston

DataAq

Loanedequipment

controller

)

Di-155

Software

Reference(LabVIEW)

MATlab

C/C++

j a v a

Simplicity 0 1 1 1 -1 0 0 -1 1 0 1 -1 0 0 1 -1 0 1 0 1 0 1 -1 -

Accuracy 0 1 0 -1 -1 -1 0 0 -1 0 -1 -1 1 0 1 1 -1 1 0 1 0 0 1 -

Cost 0 0 -1 0 -1 1 0 0 1 -1 1 -1 -1 0 0 -1 -1 1 0 0 0 0 0 -

Durability 0 1 -1 0 0 -1 0 0 -1 1 0 0 0 0 0 -1 1 1 0 1 0 0 0 -

Ease of

building 0 0 0 1

-1

1 0 -1 1 -1 1

-1

-1 0 -1 -1 0 1 0 1 0 1 -1 -

Ease ofimplemen

tation 0 1 -1 1

-1

0 0 -1 1 0 1

-1

1 0 -1 -1 1 0 0 0 0 0 0 -

Versatility

of

componen

ts 0 1 1 0

1

1 0 -1 -1 -1 -1

-1

1 0 0 -1 -1 0 0 1 0 -1 1 -

Time to0 -1 -1 1 -1 1 0 -1 -1 -1 1 -1 -1 0 0 -1 -1 1 0 1 0 1 -1 -


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build

Aesthetics 0 0 0 0 1 0 0 0 -1 -1 -1 -1 1 0 -1 0 1 1 0 0 0 0 0

Sum 0 4 -2 3 -4 2 0 -5 -1 -4 2 -7 1 0 -1 -6 -1 7 0 6 0 2 -1 -


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Table 8. Concept Scoring Matrix with Wining Concept Highlighted

Simplicity Accuracy Cost Durability

Ease of

build

Ease of

impl.

Vers. of

comp.

Time to

build Aesthetics Total

Radial

Motion

Rail Screw

Drive 5 5 5 5 5 5 5 5 5 5

Rail Wheel

Drive 7 2 5 3 6 5 5 7 5 4.64

Belt Drive Rail 4 4 5 4 5 4 4 6 5 4.41

Azimuthal

Camera Rail

System 5 6 7 4 6 5 6 6 4 5.1

Commercial

Rail 5 1 5 5 5 5 5 5 5 4.9

Vertical Scissor lift 5 6 4 3 4 8 7 4 6 5.56

Screw lift 5 5 5 5 5 5 5 5 5 5

Data Aq

Loaned

equipment 7 8 9 7 7 5 5 8 6 6.74

Micro

controller 5 5 5 5 5 5 5 5 5 5

Di-155 6 7 5 7 7 5 8 7 5 6.44

Software LabVIEW 5 5 5 5 5 5 5 5 5 5

MATlab 7 5 4 6 8 6 4 7 6 5.91

C/C++ 3 6 6 4 2 4 6 4 5 4.45


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Weights: 0.08 0.2 0.04 0.12 0.1 0.2 0.1 0.11 0.05


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System-Level Design6.The high-level system design will combine all of the top concepts from the concept

scoring matrix. The rotor wake survey system will be a curved azimuthal track on top of which a

dolly will sit. The dolly will be attached a curved rac and pinion gear system to control its

motion. On top of the dolly will be a linear camera rail system to move radially. A scissor lift

will be mounted on top of the radial system to move the pitot probe vertically. Both the radial

and vertical components will be powered by screw drives. A MATLAB user-interface will be the

front end for the software to set the measurement positions and display the collected data.

Figure 6. Azimuthal camera rail system

Figure 7. First-Generation alpha-prototype of the system


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Special Topics7.

7.1. BudgetBelow is the teams up to date budget. It accounts for all recent expenses along with the

expected expenses for traveling, prototyping, and final product construction.

Table 9 Current Project Budget

Part Price($) Quantity Total Vendor

Estimated

Data acquistion system 150 1 150 n/a

Travel Cost 224 1 224 n/a

Prototyping Cost 100 1 100 n/a

Final Product Cost 224.3 1 224.3 n/a

Poster 70 1 70 n/a

0 n/a

Actual

1x1x7 Premium FurringStr 6.88 1 6.88 Lowes

3/4 INX1OFT PVC

Pipe 4.36 1 4.36 Lowes

EMT Conduit 5ft 3.3 1 3.3 Lowes

1x2x8 Premium Furring

STR 1.12 1 1.12 Lowes

DRYWALL SCREWCRSE 2'' 4.37 1 4.37 Lowes

1/2 Compression Con 2.28 1 2.28 Lowes

3/4" SCH40 TEE 1.38 1 1.38 Lowes


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3/4" Coupling 0.54 1 0.54 Lowes

Hex Bolt 1/2 x 1-1/2 3.84 1 3.84 Lowes

Hex Nuts 0.88 1 0.88 Lowes

Skateboard wheels 1.25 8 10 Penn Skate

Wooden Dowel Rod 1.42 1 1.42

Home

Depot

Handy metal conduit

boxes 1.64 2 3.28

Home

Depot

0.75in PVC tee

couplings 0.47 4 1.88

Home

Depot

12in threaded rod 1.17 1 1.17

Home

Depot

24in threaded rod 1.76 1 1.76

Home

Depot

Stepper Motor,

Unpolar/Bipolar, 200

steps/rev 19.95 1 19.95 Pololu

Stepper Motor, Bipolar,200 steps/rev 12.95 2 25.9 Pololu

A4988 Stepper Motor

Driver Carrier 9.95 3 29.85 Pololu

Total Budget: 1000

Sales tax to be applied to all

expenses Sales Tax: 0.06

RemainingBudget 53.9924

Amount Spent: 946.0076


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7.2. Gantt ChartIn order to keep ourselves organized we are keeping all of our documents in a shared

group folder on Google Doc. We found a useful Gantt chart program written specifically for

Googles spreadsheet feature. Knowing the start and end dates of a project, if the Percent

Complete value changes, then the Gantt chart automatically updates. It is a very powerful

program. However, its code is not compatible with Excel and the spreadsheet is too large (in

length) to export as a reasonably-sized picture. Table 10 has the first and most informational

portion of our Gantt chart. Table 10 includes all project tasks, their respective state and end

dates, percent complete, and who is in charge of each task.

Table 10. Gantt Chart


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7.3. Risk ManagementGiven the nature of this project with its high-speed, large-diameter rotor, and complex traversing

system, there are significant risks involved in properly designing the system. The most critical

risks associated with this project are personnel safety and equipment safety: in operation, the 6ft.

diameter rotor will be spinning at approximately 2400rpm. This can cause significant harm to

any persons or the probe should either come in contact with the blade. To alleviate this risk, the

system will be designed such that the probe can get close to the rotor blades but it can never

come in contact with the blades. For user-safety, this system will only be used by trained


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professionals/students in a controlled testing environment so as a first-level precaution we will

require all personnel maintain a certain safety radius away from the system. We will look into

installing a safety cage or similar object around the system to keep people from coming in

contact with the rotor blades. If funds or time are short, we will look into borrowing a safety

cage.

Table 11. Risk Plan Table

Risk Level Actions to Minimize Fallback Strategy

Change in

Customer

needs

Low - Keep sponsors always up to date

on project developments and

design decisions

- Additional money required

- Factored in 3 different

design-build-test stages into

project schedule

Rotor bladesharm

equipment or

people

High - Design traversing system suchthat the probe can never come in

contact with the blades

- Require operators to stand a

specified number of feet away

while rotor is in operation

- Do not allow bystanders to come

near rotor blades

- Do not operate around untrainedprofessionals

- Install sensors or barricadesto prevent probe motion

- Install a protective cage

around the entire system

Traversing

system cannot

move in 3

dimensions as

designed

Moderate - Test early and often (3 design-

build-test iterations factored into

schedule)

- Consult with sponsors and other

professionals on the selection and

implementation of hardware to

ensure proper choices are made

- Use proven technology

- Manually position probe

- Design for minimum

requirements outlined in

project description

Sponsors not

satisfied with

the system

Low - Constantly keep in contact with

sponsor and reiterate via e-mail

what is discussed in meetings so

there is a written copy to avoid

- Discuss how to fix/work-

around problems


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confusion

Schedule

Delays

High - Constantly track and report on

progress

- Try to work ahead on simpletasks

- Make a small number of large

orders not a large number of small

orders

- Make parts ourselves

- Contact supplier to express

urgency (e.g. the squeakywheel gets the grease)

- Pick it up ourselves

- Buy locally

Stand is

incompatible

with

traversing

system

Moderate - Discuss modifications to stand

with sponsors.

- Redesign system to work

with the stand

Rotor wake

shakes probe

and traversing

arms

Low - Design traversing system as rigid

as possible.

- Avoid cantilevered arms in

design

- Operate at sufficiently low

speeds such that the rotor wake

buffeting is minimal

Data

acquisition

system doesnot function

as designed

Moderate - Consult with professionals on

proper use of hardware and

software to ensure compatibility

- Test often to make sure controls

and sensors work as designed

- Purchase a functioning data

acquisition system

- Design to minimum

requirements

- Use multiple software

systems for inputs and outputs

Project runs

over budget

Low - Extensively research existing

products to ensure we purchase

the best-value product

- Avoid buying wrong hardware

- Minimize orders to minimize

shipping costs

- Build hardware ourselves

- Negotiate with vendors for

lower prices/donations


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A majority of the other risks associated with this project are of moderate intensity or greater.

These risks deal with everything from scheduling delays to probe positioning and data

acquisition issues. To avoid as many issues as possible we plan to keep in constant contact with

our sponsors and consult with seasoned professionals on hardware and software designs.

Moreover, to further take into account time constraints and operational issues, we have

implemented three different design-build-test iterations into our project schedule, as seen in

Section 7.2: Gantt Chart. At the recommendation of Professor Dennis McLaughlin, we divided

ourselves into six different, two-member teams. The teams are outline in Table 12:

Table 12. Sub-Teams

Team: Leader: Assistant:

Azimuthal Motion Scott Hromisin Joe Oberholtzer

Radial Motion Ryan Hammerschmitt Dylan Wynn

Vertical Motion: Dylan Wynn Ryan Hammerschmitt

Data Aq & Controls Joe Oberholtzer Steven DrewSignal Conditioning, Circuitry, & Power Steven Drew Bill Boggs

Software & GUI Development Bill Boggs Scott Hromisin

Teams were chosen based on everyones strengths. Each sub-team will design, build, and test

their subsystem at least three times, as outlined in the Gantt Chart. By developing functional sub-

systems in parallel, the entire system will come together in a shorter amount. Thus maximizing

the amount of time to fine-tune the final design and correct any unforeseen errors.

The final step in alleviating risks is a project map. The project map is a block-diagram model ofour entire project. It shows, qualitatively, what parts of the project run in parallel and which are

in series. The benefit to such a map is that it clearly defines the critical path for our project. The

critical is the path in the project map, from project start to project end, defined by the activities

that have the longest duration. These tasks define the length of our project. All of the tasks not on

the critical path make take longer or shorter than expect yet not necessarily have any effect the

end date of the project. In Figure 8, the critical path is marked as bold arrows.


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Figure 8. Project map with Critical Path in bold


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7.4. EthicsEthics are a very important part of any project. Many problems have arisen from a lack of ethics.

A lack of ethics includes anything from stealing someone elses data to not using the necessary

safety precautions. Our team has made sure that we are doing everything as safe as possible. We

have also conducted a patent search for every different aspect of our design to make sure we arenot taking someone elses idea. We have referenced every idea that we have loaned or acquired

from someone else and we will continue to maintain this responsibility.

7.5. EnvironmentThe environmental impact of the solution is important and will be incorporated into the design

and manufacturing. Hazardous materials of grease, oil, and fuel are used in the test stand but are

easily avoided in the solutions design. Power consumption ofour device should be relatively

small as minimal electronic circuits and small motors will be used. The manufacturing

techniques and material selection will be driven primarily by our limited budget, this

complements the effort towards sustainability as abundant and easily accessible materials andtools are typically eco-friendly.

7.6. Communication with SponsorTo ensure the success of the project we try to keep in constant contact with our project sponsors

Jason Steiner and Rob Spencer. We have set aside one hour a week on Tuesdays from 1:00-

2:00PM in which we all gather for conference call. During this call we formally report in on our

progress and ask any questions we may have. During the call, the note taker records what has

been discussed. After the call, the teams point of contact sends out an e-mail to the sponsors

stating what has been discussed/ decided so there is a written confirmation to avoid confusion

and possible disagreements. Should any other issues arise during the week, our point of contactwill e-mail Jason and Rob to resolve them. If immediate contact is necessary, the team has Jason

and Robs work numbers. All of our work is kept on a Google Doc that we have shared with our

sponsors so they have immediate access to it. They can see exactly what we have done. As of

now we have no plan to visit the site. The team, or at least part of the team, will most likely need

to make a visit to the site in the future to acquire the rotor stand. We will need it to make sure it

is compatible with our system.


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Changes to the Statement of work8.

8.1.1 IntroductionNo changes were made to this section.

8.1.2 Customer NeedsNo changes were made to this section.

8.1.3 External SearchThe External Search, Section 3, has been updated to include a short introductory paragraph

before each table of search results.

8.1.4 Engineering SpecificationsPer sponsor request, the target specifications for the design metrics were modified (Table 22).

8.1.5 Concept Generation and SelectionAfter further discussion and brainstorming with project sponsors Jason Steiner and Rob Spencer,

the concept design for azimuthal motion has been updated to use a lazy Susan style bearing.

Details are shown in Appendix F.

8.1.6 System Level DesignThe system level design using the new azimuth mechanism was incorporated in the detailed

design (Figure 27).

8.1.7 Special TopicsThe Gantt chart was updated for greater detail in the final design, build, test, and presentation

stages (Figure 50). The remaining funds are budgeted for anticipated needs (Table 23). The

updated Bill of material for the project is detailed in Appendix I.

8.9. Design Specifications8.9.1 Manufacturing Process Plan

The system for rotor wake surveying is being developed primarily as a proof of concept article.

Due to the complexity of the system, the goal is to keep the design as simple and cost-effective

as possible. That means few parts, fewer custom parts, simple materials, standard part

dimensions. The team has a limited budget for the entire project so it is imperative that any one

subsystem not cost more than its fair share of the budget. Time is also very limited on this

project, less than fifteen weeks, so component lead times and manufacturing time must be as

short as possible. Moreover, even though comprehensive planning goes a long way into

designing a successful product, it cannot completely replace prototyping and testing. The need

for rapid development results in parallel phases of design, manufacturing, and testing is critical.


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Azimuthal Dri ve8.9.1.1

The azimuthal drive was designed to be as inexpensive and as quick to build as possible. Many

of the parts can be purchased from a local hardware store or from a single supplier such as

McMaster-Carr. Two of the aluminum parts have a large hole in the center to accommodate the

test stand. To machine these they will need to be water jet cut. While this will cost extra, many of

the parts will be complete within a few minutes. They will need no other machining other than

tapping the screw holes. Total machining time is estimated to be 66 hours.

This system is being designed to be used in-house by Boeing. The azimuthal motion system has

taken this into consideration in that the entire project can be built in a machine shop with similar

capabilities as Penn States Learning Factory. The tools necessary to machine this system are: a

mill, miter saw, hand drill, band saw, and water jet cutter. The detailed manufacturing process

plan is outlined in Table 13.


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Table 13. Azimuthal Drive Manufacturing Process Plan

ASSEMBLY NAME MATERIAL TYPE RAW STOCK SIZE OPERATIONS

Base 6061 Aluminum 3 x 4 x sheet Water jet cut shapeand holes for stand

and screwsPlywood 2 x 2 x sheet Table saw cut to size,

jig saw hole for teststand and drill screwholes for legs andaluminum

Pine wood 1 x 2 stock Cut legs to length onmiter saw

Azimuthal Arm 6061 Aluminum (arm-bearing coupling)

3 x 4 x sheet Water jet cut to size,tap screw holes

Plywood (arm) 1 x 4 x sheet Table saw cut to size,drill screw holes

Caster Wheel ArmSupport Stand

6061 Aluminum 3 x 4 x sheet Mill to size, bore holedown center, millscrew slots, tap bore

6061 Aluminum Diameter x 12cylindrical stock

Mill to length, borehole down the center,tap bore

Lazy Susan Bearing Aluminum n/a Tap through holes forscrews, tap side hole,drill and tap a secondside hole

Timing Belt Neoprene andFiberglass

n/a Cut to length, drillholes for mounting


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Table 13.1. Azimuthal Drive Manufacturing Process Plan Cont.

Stepper Motor

Bracket and Shaft

Support

6061 Aluminum 3 x 4 x sheet Water jet cut to size

and tap screw holes

6061 Aluminum 3 x 4 x sheet Water jet cut to size,

drill screw holes in

bottom and tap screw

holes

6061 Aluminum Diameter x 12

cylindrical stock

Cut to rough length on

band saw, mill to final

length, bore center

hole

Final Assembly Screw base pieces and

legs together using

standard 2 wood

screws and washers

Attach timing belt to

bearing with screws

Screw bearing to basewith 1 wood screws

and washers

Screw arm pieces

together with 3/8 3-

48 socket head cap

screws

Screw stepper motor

to arm with screws

provided with the

motor

Screw ball bearing

into cylindrical arm

support piece, slide

cylindrical piece into


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the end of the

rectangular support

piece and screw

together with threaded

knob, washers and

hex nut

Bolt arm support to

arm with a 3/8-24 1

screw.


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Radial Dr ive8.9.1.2

In prototyping the design it is important to create a cost effective solution for moving the probe

in the radial direction with as much accuracy as possible. For this reason a design based on a

camera rail is being pursued that can be adapted to the project needs. This design is cost effective

and allows a quick proof of concept. Most of the components for the build can be acquired at a

local hardware store. Since most components of the design were store bought it will be easy to

mass produce the design. However, in case the project will be a proof of concept and will not

need to be reproduced. A few parts will need to be custom made for the design to be completed.

Keeping simple parts and accurate shop drawings will allow for easy rebuild and help the

sponsor to utilize the design as effectively as possible. Two journal bearings, a coupler, and a

drive will need to be fabricated for the radial portion of the project (shown below). The design

for these pieces is created with simplicity in mind to reduce manufacturing and material costs.

These parts will take approximately 11 hours of machining time to create and implement into the

radial system. Using a lathe, drill press, and a few hand taps it will be easy to create the parts

required. Since most machine shops have this equipment, the parts can be manufactured almostanywhere. The following breakdown will show the work needed to prepare the system for

assembly.

Figure 9. Radial Drive Close-Up


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Table 14. Radial Drive Manufacturing Process Plan

ASSEMBLY

NAMEMATERIAL TYPE RAW

STOCK

SIZE

OPERATIONS

Slide Rails Electrical Conduit X 5HollowCylinder

Cut to length on metal bandsaw

Sand on belt sander to clean edges

Affixed threaded coupler

End Piece Electric Box 2 X 4Steel

Purchased two

Slide Platform Wood, 4 pvc tees,wood screws

5 X 1

PlywoodBoard

Trim to size

Drill hole locations and mount pvcwith wood screws, sand smooth

Motor andCoupler

StepperMotor, AluminumStock

" X 6

RoundTurn to size on Lathe

Drill 0.2 hole through center then1/2 hole from other side use cut off

tool to remove from lathe


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Table 14.1. Manufacturing Process Plan Example (Contd)

ASSEMBLY

NAMEMATERIAL

TYPERAW STOCK

SIZEOPERATIONS

Drive Aluminum stock Square X

4

drill two 59025 holes from side into

center on drill press

Deburr on flywheel

Tap 4235 holes into side of coupler forset screws

Journal bearing Aluminum 1 X 4Round

Turn to size on Lathe

Cut notch for retaining ring

Drill 1/2 hole

Use cutoff tool to remove from lather,deburr with flywheel

Drive Aluminum " Sq x 4 Cut to size using band saw

drill two holes for bolt fastening

Drill, debur, and tap 13 drive holefor threaded rod

Vertical Dri ve8.9.1.3

The components for the prototype scissor lift for the vertical motion component are

manufactured using a combination of manual machining and water-jet cutting, with a drill press

to drill the holes and hand taps to tap the threads. The manufactured pieces are then assembled

by hand, using standard fasteners. The mass production version uses CNC machining processes

in place of the manual machining processes, drilling, and hand tapping used for the prototype. In

order to simplify the manufacturing of the components, stock material sizes are used wherever

possible. This will cut down considerably on machining time, and reduce the overall cost of the

design.


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Table 15. Vertical Drive Manufacturing Process Plan

ASSEMBLY

NAME

MATERIAL TYPE RAW STOCK

SIZE

OPERATIONS

Base/top side 6061 Aluminum 1' x 2' x 1/4" Cut on waterjet

Sand edges

Base/topconnector

6061 Aluminum 1/2" Sq x 48"rod

Cut to size w/ bandsaw

Sand edges

Arm 6061 Aluminum 1' x 1' x 1/4" Cut on waterjet

Sand edges

Arm connector 6061 Aluminum 1/2" round x 48"rod

Cut to size on lathe

Sand edges

Drill & tap holes in endswith #8-32 tap

Drive armconnector

6061 Aluminum 1/2" Sq x 12"rod

Cut to size w/ bandsaw

Sand edges

Drill & tap holes in endswith

Drill & tap hole for threadedrod with 5/16" - 18 tap

Motor mountplate

6061 Aluminum 1' x 1' x 1/4" Cut on waterjet

Sand edges


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Table 15.1. Vertical Drive Manufacturing Process Plan (contd)

ASSEMBLY

NAME

MATERIAL

TYPE

RAW STOCK

SIZE

OPERATIONS

Base Weld base sides to base connectors

Top Weld top sides to top connectors

Scissormechanism

Connect scissor arms to armconnectors using #8-32 screws

Motor mount Mount stepper motor to mounting plateusing screws

Attach motor mounting plate to baseconnector

Drivetrain Connect coupler to stepper motor

Connect threaded rod to coupler

Thread rod through driven scissorconnector

Final assembly Mount top assembly to scissormechanism

Mount scissor mechanism to baseassembly

Data Acquisiti on & Controls8.9.1.4

For the data acquisition and controls are elements of the modular electronics design. The

complete electronics package consists of data acquisition, controls, signal conditioning and

power supply modules. Ideally each module is a commercially available component and the

design is performed at a systems level. However, in practice custom components are needed at

the intersections of the modules.

The circuit design is complete and is tested on a breadboard. In parallel the printed circuit board

design is completed and manufactured. The mass manufactured model will likely integrate thedata acquisition, controls, and signal conditioning into a single system to optimize for

manufacturing and reduce costs.


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Table 16. Data Acquisition & Controls Manufacturing Process Plan

ASSEMBLY

NAMEMATERIAL

TYPERAW STOCK SIZE OPERATIONS

Pressure Sensor Silicone Tubing 1 ft x 1/8 in Cut tube into 6in sections

Pitot Probe 4mm Diam x 11cm Attach one half to eachoutlet

PressureTransducer

MPXV7002DP0-2.5psi

Attach one half to each inlet

Mother StepperMotor DriveCircuit

Pin Header 48 Male Pins

Stepper MotorDriver Carrier

A4988 Solder header pins to carrier

Capacitors 100uF, 50V Solder components toMother Driver PCB perFigure 23

Mother DriverPCB

Figure 23

DAQ and Controls(Finished Assy)

Assemble PerFigure 65

Signal Conditi oning and Power8.9.1.5

Initially, while the signal conditioning and a power supplying circuit is in the design phase, it is

simulated with both circuit simulator software, Multisim, which was produced by National

Instruments, and breadboard configurations. Then, for manufacturing purposes, the design is

transposed into a printed circuit board using Ultiboard software. With Ultiboard we are able

bring our design from a basic prototype, to a more scalable product. Our plan is to use low power

consumption to reduce the cost of the electrical design.


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Software/GUI Development8.9.1.6

The objective of the initial prototype was to figure out the most cost effective way to create the

software needed for the system. The software design calls for programming a microcontroller to

control motor motion,position a pressure probe at the users request, and read data obtained

from a pressure probe. An Arduino Mega 2560 microcontroller is being implemented to control

the motors and read data from the pressure probe. Software design for the system involves two

different parts: Motor control and pressure probe reading. The prototype starts with

communicating with the Arduino through a graphical user interface (GUI). The GUI prompts the

user of the program to enter three coordinates: The Azimuthal coordinate, Vertical coordinate

and Radial coordinate. Once the three coordinates have been entered by the user, a c++ language

software program obtains the input and sends the data through the serial port of a computer to the

Arduino Microcontroller for interpretation of the data sent. The microcontroller coding then

translates these data values to integer values and transfers control to another c++ program that

sends signals to digital out pins on the Microcontroller. These digital out pins send data to the

stepper motor driver, which then converts the signal to a value of voltage that can move themotor. After the azimuthal, radial and vertical motors move to their respective positions, the

pressure probe takes the pressure of the location. This pressure value is sent to the Arduino in

analog form for the Arduino to interpret. The Arduino software code then sends this pressure

data to the computer and the software on the computer outputs the pressure data to the GUI. If

this product were to be mass produced the prototype GUI must evolve to a more user friendly

program. More tests are being run to make the software more fool proof.

Table 17. Manufacturing Process Plan

ASSEMBLYNAME Languauge CODE SIZE OPERATIONS

GraphicalUser Interface(GUI)

C++ coding Around 150lines of code

Ask the user what lengths they want to movethe Azimuthal, Radial and Vertical Length

Code makes sure the user doesnt input and

invalid option

Outputs a graph of the measured data fromthe pressure probe

Motor ControlCode

C++ coding Roughly 500lines of code

Moves the Azimuthal, Radial and Verticalmotors

Pressure probereading code

C++ - Matlab N.A. Arduino code sends data through the serialport to the computer

The code takes in the serial data from the


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Arduino and graphically represents it on theGUI

F in ished Product8.9.1.7

The parallel development of the subsystems results in a modular completed product. The

independent manufacturing lines feed into a simple final assembly. Assembly of the components

can occur as the subassemblies are completed, preventing schedule delays in both prototype and

bulk manufacturing.

Table 18. Manufacturing Process Plan

ASSEMBLY

NAMEMATERIAL

TYPERAW

STOCK

SIZE

OPERATIONS

MechanicalAssembly Bolt together the azimuth, radial, andvertical drives.

ElectricalAssembly

Connect the control, signal conditioning,and power supply modules to the DAQ(Arduino)

Final Assembly Connect computer with software to DAQ(Arduino)

Connect control module to drive motors

8.9.2 AnalysisAzimuthal Drive8.9.2.1

After designing the alpha prototype, the need for many improvements was realized. The biggest

issue came in the form of the spacing between the outer and inner dolly rails. Each rail was not

kept at exactly a constant radius so the spacing between the rails varied by over an inch over the

span of 90 degrees. This caused the dolly to derail. The design was also bulky and required many

parts. At full scale, the alpha prototype would have an 11ft diameter. A base this big would

quickly prove to be quite cumbersome. Constructing accurate metal rails (instead of bent PVC

pipe) would exceed the capabilities of most machine shops, including the Learning Factory.

Thus, bending the rails would have to be outsourced to a vendor which would increase the

projects overall cost and manufacturing time. In addition, the dolly system had a high profile at

about 9 which limited the range of vertical motion for the probe. The new azimuthal system

cuts that profile height down to 5.88: a 36% reduction in height.


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Figure 10: Profile CAD drawing of azimuthal section with floor-arm height measured

Due to physical size and project time and cost, the alpha prototype would have only allowed for

only 90 degrees of azimuthal motion. The new concept should allow for 178 degrees of

azimuthal motion. This could easily be extended to 180 degrees but would require processes

not available or affordable for students given timeline and budget constraints.

The original concept was to create a third radial track, concentric with the other two and

positioned between them. A timing belt would be cut and mounted to this third track with the

teeth facing inward. It would act as a flexible rack. The pinion would be the timing belt pulley

attached to the stepper motor and mounted to the underside of the dolly. While the concept is

sound, a major issue with implementing it in the alpha prototype is the positioning of the third

track. It needs to be almost perfectly concentric and very accurately positions so the pinion stays

coupled to the belt and does not cause the system to jam. However, this fixed-belt concept works

very well with the current design. The belt can be attached directly to the outer diameter of the

lazy Susan bearing thus ensuring its concentricity with the rest of the system.

An exhaustive engineering analysis was performed on the current system design. It is imperative

to ensure to the design will actually work in practice before manufacturing begins. The goal of

the calculations were to ensure a) the stepper motor could provide enough torque to turn the arm,

b) the overhung load and bending moment on the motor shaft were sufficiently small, and c) the

stresses and forces on the belt and pulley were not too large.

To begin the calculations it was necessary to know the torque required to rotate the arm. In order

to determine this accurately, a mock-up of the design was constructed in the Learning factory:

the bearing was mounted on stilts and a 46 wooden arm with a caster wheel was attached to the

bearing. Two 7lb, 3.5 bars were placed on the arm to simulate the weight of the radial and

vertical systems. A 4lb force gauge was hooked to the end of the arm and pulled manually. The

force indicated by the gauge at the onset of motion was recorded. This force multiplied by the

arm length yielded the minimum torque the stepper motor had to generate. It was found that even


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with the current belt-pulley gearing, the system could not be driven by the current stepper motor

that was intended. A motor as strong as that currently being employed by the vertical drive

would be ideal.

Figure 11. The motor used on the vertical drive (left) and the motor originally intended forthe azimuthal drive (right). The vertical motor provides 1.73in-lb of torque whereas the

radial motor supplies 0.70in-lb of torque. Photos courtesy of Pololu.com.

To account for the predicted bending stresses on the motor shaft, a special shaft support

assembly has to be installed on the system. The motor shaft will be coupled to a second shaft.

This second shaft holds the pinion gear and is supported by two pillow block bearings to take the

bending stresses off of the motor shaft. The final results of all calculations are listed in Table 19.

Complete calculations with all work and assumptions can be found in Appendix G.

Table 19. Final Results of System Analysis Calculations

Variable English Value Metric Value

Torque Required 3.41 ft-lbs 4.62 N-m

Tangential Contact Forcebetween Belt and Pulley

4.06 lbs 18.0 N

Radial Contact Force betweenBelt and Pulley

3.15 lbs 14.0 N

Bending Moment on MotorShaft

0.26 ft-lbs 0.35 N-m

Gear Ratio 31.6 31.6

Minimum Motor TorqueRequired

0.108 ft-lbs 0.146 N-m

Bending Stress (Pinion) 814 psi 5.61 MPa

Surface Stress (Pinion) 979 psi 6.75 MPa

Bending Stress (Pulley) 814 psi 5.61 MPa

Surface Stress (Pulley) 979 psi 6.74 MPa

Bending Stress on Motor Shaft 12 ksi 82.74 MPa


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From the alpha prototype it was quickly realized that accuracy needed to be improved

significantly. The first model allowed the radial platform to wiggle significantly which combined

with the scissor lift would make it difficult to find accurate results. To address this problem a

tighter fit between the rail and the slide must be created. The prototype created proof that the

radial design was plausible. The table was able to slide freely and the rails will be able to support

the weight that is expected. The design is slightly over designed for weight since the electrical

conduit will be able to support three or four times the weight of the pitot probe and scissor lift.

For this reason no calculations for strength or bending were performed. Since the alpha prototype

performed the necessary functions for the final design it will only need an added threaded rod to

drive the lateral motion. This will keep the design process short and the design simple.


No stress calculations or FEA were used as the scissor lift was designed with stability in mind.

To maximize stability, all load-bearing components were over-designed, to the point that none of

the loads experienced by these components will come close to the failure point.

The torque required by the motor to turn the threaded rod was calculated using the followingequation:


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Where Tm is the required motor torque, W is the weight to be lifted (estimated), is the

minimum angle of the scissor arms, and Req is the equivalent moment-arm of the threaded rod.

From the initial prototypes, it was clear that stability was going to be an issue with the scissorlift. This will be remedied by using stiffer scissor arms and having cross-members connecting the

scissor arms at every joint. We also learned that as the angle of the scissor arms gets smaller, the

torque required to urn the threaded rod increases dramatically. This can be remedied by over-

sizing the motor, or by limiting the minimum angle to which the scissor arms can lower. The

early prototypes also demonstrated the importance of having the connections for the scissor arms

perfectly centered. If the center connection of the X portion of the scissor lift is not centered

perfectly on the scissor arm, the mechanism will not function as desired. This issue will be

remedied by using a water jet to cut the holes, assuring that the holes are centered perfectly on

the scissor arms.


The data acquisition capabilities of an Arduino and the motor control capabilities of an Arduino

with the A4988 chip has been proven beyond the demands of our system. With real world

validation of the design already available, only minor trouble shooting is expected. Basic

analysis was performed to assure the combination of systems would not pose a problem.

Ultiboard software determines the trace width and component placement for a printed circuit

board.


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Noise filtering circuit:

Instead of using active load, we deciding that using a passive circuit with resistors and capacitors

would be more appropriate, and the necessary components are in the available inventory.

Stock room capacitor available: 100uF: The time constant for the given circuit : Resistance in series of load capacitor: Capacitance of load Capacitor

=16

The equations above apply for low frequency cut off point.Amplification Circuit:

Using a simple non-inverting op amp configuration


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=5Av = Gain of Amplification Circuit

With the amplification and noise filtering circuit coupled together, there seems to be a change in

some of the characteristics, some good and some bad. For instance, when coupled together there

appears to be an offset in the voltage, but that could be changed simply by applying an additional

1 volt voltage into the op-amp or to make simple adjustments. In terms of the bode plot, the

amplitude decays faster for the unwanted frequencies, which is a plus.

Software/GUI Development8.9.2.6

Simple math equations were necessary to convert the three user inputted data points to an

amount of step pulses for the Arduino Microcontroller to read. Testing the prototype creates an

accurate measurement of how far in length a specified amount of motor steps actually goes.Measuring these lengths creates a conversion equation to change length to an actual amount of

motor steps (amount of pulses that need to be sent out to the motor driver). Measuring the length

of each motor step is essential to creating a reliable conversion equation.

An Arduino microcontroller was used in conjunction with software design because it is an easy

to use and reliable microcontroller. Coding an Arduino is simpler than other microcontrollers

because of the vast open source Arduino coding community. 11 and visual studio c++ has the

biggest Windows function code library. This gave c++ a slight advantage over other languages

such as Java or Matlab.

Features of the software design are divided into two large components: Motor control software

and the pressure probe data acquisition software. Motor control software starts with the GUI and

ends with actual motor movement. The pressure probe then reads the value of the pressure at the

point the motors move to and sends the data to the Arduino microcontroller. Microcontroller

coding reads the data, interprets it, and sends the interpreted data back to the computer for output

on the GUI. The computer makes its own interpretation of the microcontroller data by software

coding, which then translates this data to data understandable to the user.

8.9.3 Material Selection ProcessAzimuthal Dri ve8.9.3.1

The primary materials being used for this design are aluminum and plywood. Three major

factors in choosing materials for the azimuthal drive are a) both are relatively inexpensive

compared to other engineering materials, b) they are readily available for use at the Learning

Factory or can easily be procured from a local hardware store, and c) they have more than


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sufficient strength properties for the given application. Another driving force is the machinability

of the materials. Easily machined materials reduce manufacture time which is a big aid in

making quick prototypes or testing an idea on the fly. It also means that if a major component

does not work or breaks, it can be quickly replaced at a low cost. One tradeoff that exists lies in

using the plywood. With the current shop facilities in Reber and the Learning Factory, wood

products can only be made to about 0.1-0.2 of design specifications. This issue is mitigated by

only using wood in parts that can afford to be less precise and not have a major effect on system

performance. For joining pieces, screws, washers, and hex nuts readily available at the Learning

Factory are being used. This reduces expenses and has no lead time. Less general screws that are

needed will be purchased from McMaster-Carr or a local hardware store.


For this design electrical conduit and electrical boxes will be utilized to create the radial rail

system. By punching out the three tables in our electric boxes we can us couplers to connect the

conduit to them creating a rail system will create a stable platform to build off of. These parts are

only sold in steel components. Since these parts will be easy to work with, the will not need to be

any significant modifications. The threaded rod will also be made of low strength steel since this

was the most cost effective solution that would still provide enough rigidity to avoid bowing.

The rest of the components will be made of aluminum. This material is lightweight and easy to

work with. After some quick research it was discovered that aluminum on steel will not bind.

However since aluminum is so soft damage in journal bearing after the system is run for an

extended period of time is imminent. Since this will be a proof of concept this concerned with

damage will be neglected in the short term. In the future if the design is utilized it will be

possible to make these bearings out of a harder material and the threaded rods can be either

shave down or fitted with a sleeve.


Aluminum stock was chosen for the prototype because of its availability, machinability, low

weight, high strength, and low cost. Steel was also considered for its greater strength, but its

greater weight and cost made aluminum a much more desirable option. Steel is also much more

expensive to cut using a water jet, making aluminum the clear choice.


For the printed circuit board the use of laminate, copper etching and prototype boards were

considered. Etched copper board is used because of the greater manufacturing flexibility and

shorter lead times than laminates. Copper etched board is also a more accurate representation of

a mass produced board than a prototype style board.


The signal conditioning circuit is configured such that the design could utilize parts from the

Electrical engineering stock room. This minimizes the cost by using materials that are already

readily available. The circuit will also be configured for low power considerations.


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8.9.4 Component Selection ProcessAzimuthal Dri ve8.9.4.1

From the engineering analysis performed, the bending stress on the stepper motor shaft caused

by the overhung load is on the order of 16 ksi, using a safety factor of 2. The stepper motor

manufacturer did not list the shaft material so it was taken to be aluminum with a yield strengthof 35 ksi. Even though the azimuthal system could function under these conditions, its life span

would be compromised.. The motor was not specified an overhung load capability. This loading

would result in faster degradation of the motor bearings and a shortened motor shaft life. To

increase the robustness of the system, a special bracket and shaft support assembly is included in

the design to take the bending stress off the motor shaft.

Figure 12. Motor attached to shaft support assembly

The major tradeoff here is the increase in cost, complexity, and size of the system with the

bracket included. Cost is expected to increase $50, six new custom parts are required, additional

machining to the arm is necessary, and the arm is raised an additional 1.5 off the floor. The

justification for using this bracket is that there is more than enough room in the budget to handle

the added expenses. At week 9, with most major purchases made (before the cost of

manufacturing the azimuthal drive), there is still $600 left in the budget. Moreover, the processes

necessary to machine the extra parts are not overly complex: water jet cut, mill, drill, and tap.Manufacture time should not increase by more than 3 hours for someone decently-versed in the

aforementioned machining processes. The increase in height still provides a 36% in height from

the previous prototype. The height increase is further justified by the fact that the life span of the

system is expected to increase significantly. An added bonus of this feature is that the pinion

location is not variable. Using a system of four sets of screws, nuts, and washers, the pinion


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location can be moved radially and then fixed into place to ensure optimal coupling the timing

belt.

Another feature of the system is the variable height caster wheel arm support assembly. With the

use of a level, this feature allows the operator to ensure the azimuthal arm is sufficiently

horizontal before taking any measurements. The height is adjusted by the use of threaded knoband two hex screws. When loosened, the caster wheel can move vertically, and then it can be set

to a fixed height by pinching the shaft to the support arm with the knob and screws. One issue

that can arise with this feature is the knob coming loose and thus causing the arm to drop below

the horizontal. To get around this problem, two hex nuts are used. The first one works in

conjunction with the knob to provide the necessary pinch to hold the arm at a constant height.

The second nut provides a level of redundancy: it is jammed against the first nut to prevent it

from coming loose during operation.

Figure 13. Threaded knob to be used on caster wheel/arm support. CAD model courtesy of

McMaster-Carr.

The final and most innovative feature of the azimuthal drive is the fixed timing belt. The timing

belt is cut and wrapped around the outer diameter of the lazy Susan bearing 356 degrees. The

belt is held in tension with a screw at each end; this tension keeps the belt from moving during

operation. The fixed belt acts as a flexible rack while the timing belt pulley becomes the pinion

to crawl along the belt and move the arm. The curved belt also acts like a giant gear thus

amplifying the torque stepper motor.


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Since the design process builds on the alpha prototype, most of the focus is on motorizing the

radial design. Fitting the electrical boxes in the original design with journal bearing allows us to

drive the radial table with a screw. The screw driven design allows the probe to move accurately

and smoothly, however, this motion is slow. The journal bearings allow quick manufacturing

since they are aluminum. However this is a trade off with strength since the journal bearing will

only last for a short period of time. The coupler and drive that was selected is the simplest

functioning design that could be created. Fewer parts make the system easy to maintain which is

in the best interest of the sponsor.


The design is made nearly entirely of machined aluminum stock. The use of stock material sizes

reduces the amount of machining required, leading to a reduction in production time and

ultimately a substantial cost savings. A stepper motor is used to drive the lift so that position can

be accurately controlled without the need for a position sensor. Because the height of the scissor

lift is a non-linear function of base separation, the software will need to be calibrated to

accurately determine the position.


The concept selected for the Data Acquisition and Control system is centered around the use of a

loaned data acquisition system. However, the concept of a microcontroller based data acquisition

is being used following logistical issues in loaning a data acquisition system. The design uses an

Arduino microcontroller because of the significant documentation readily available on similar

projects. The team also is positive past experience Arduino based systems.

Specialized circuitry is required to control the stepper motors in the mechanism. Where possiblethe design uses commercially available circuits as opposed to custom circuitry. Commercial

circuits provide a simple interface with the Arduino, reliability and comparable price to custom

solutions.


In the component selection phase simplicity, desired performance and available inventory are

large drivers. Simplicity is necessary because for the tight time schedule. The desired

performance is determined by the design metrics and the other systems with which the circuits

are interfacing. With a significant available inventory, component selection is not heavily

influenced by inventory. Matlab coding was originally selected to be the coding choice forsoftware design. Since Matlab coding didnt have the needed built in functions for serial port

communication, it was decided that the design use c++ coding. The c++ coding language has a

vast library of GUI creation and has many built in functions that work with Microsoft Windows.

Since the software is designed to run on Microsoft Windows, c++ coding was chosen. Another

reason for using c++ is the arduino microcontroller. The microcontroller can be coded in c or

c++ which makes it easier for compatibility purposes if the computer software is coded in c++.


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8.9.5 CAD DrawingsAzimuthal Dri ve8.9.5.1

Four different CAD drawing are provided to provide a general overview of the azimuthal system.

Two drawings show the entire system while two more provide a more detailed view of the CasterWheel Arm Support Assembly and the Stepper Motor Bracket and Shaft Support Assembly.

More detailed drawings of specific components may be found in Appendix A: Shop Drawings.

Figure 14 Azimuthal SystemIsometric View

Figure 15. Azimuthal SystemFront View


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Figure 16. Azimuthal SystemFocus on Caster Wheel Arm Support Assembly (front)

Figure 17. Azimuthal SystemStepper Motor Brac

final report - boeing 4

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