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P09561: Visible Spectrum Imaging System MSD I Detailed Design Review

Group Members:

Steve Sweet Dave Lewis

Darrell Draper Jason Thibado Joanna Dobeck

Lenny Calabrese

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Table of Contents

Project Summary………………………………………………………………………………………………………….. 3 Customer Needs…………………………………………………………………………………………………………… 5 Engineering Specifications……………………………………………………………………………………………..5 Selected Concepts VIS……………………………………………………………………………………………………………………………. 6 Frame...………………………………………………………………………………………………………………….. 15 Camera…………………………………………………………………………………………………………………… 20 Microcontroller/Software……………………………………………………………………………….……... 25 Power…………………………………………………………………………………………………………………….. 30 Bill of Materials…………………………………………………………………………………………………………… 34 Action Items……………………………………………………………………………………………………………….. 35 Risks/ Risk Mitigation………………………………………………………………………………………………….. 37 SDII Plan……………………………………………………………………………………………………………………… 40 Test Plan…………………………………………………………………………………………………………………….. 42 Appendix…………………………………………………………………………………………………………………….. 44

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Project Description

Project Background: Imaging Scientists often use aerial photography in their studies. Due to the size and weight of current systems, they must be mounted into small single engine airplanes or helicopters. This makes the cost of flight time take up a considerable amount of a project’s budget. By designing a much smaller ground controlled imaging system to be used on an Unmanned Aerial Vehicle; this cost can be greatly reduced while still acquiring useful research photography. This first phase of the project is mostly a proof-of-concept using a visible spectrum camera. Future phases may use other types of camera systems such as infrared cameras or spectrometers.

Problem Statement: The purpose of this project is to design an imaging system that can be mounted onto an Unmanned Aerial Vehicle and can be controlled from the ground. This project includes vibration damping to ensure clear pictures, a microcontroller to relay commands to the camera and the proper interface to do so as well as a power supply for the system.

Objectives/Scope: 1. Lightweight and compact system. 2. Wireless control. 3. Vibration Isolation for clear images. 4. Autonomous image capture.

Deliverables: • Functional Imaging System that meets

project needs. • Required documentation.

Expected Project Benefits: • More cost effective aerial research method

for Imaging Scientists. • Basis for future senior design projects

Core Team Members: • David Lewis – Project Co-Lead • Steve Sweet – Project Co-Lead • Joanna Dobeck • Darrell Draper • Jason Thibado • Lenny Calabrese

Strategy & Approach Each subsystem of the imaging system has been researched in order to decide upon materials and components. This includes comparison of microcontrollers, available cameras and other camera components. A means of interfacing the camera and microcontroller has been decided upon as well as a means to power the system. A concept has been selected for housing the system as well and mounting it to the airframe and methods of vibration isolation have also been investigated.

Assumptions & Constraints: 1. The size and weight of the system are

constrained by the payload dimensions and carrying capacity of the UAV-Airframe B project.

2. Budget of around $2000.

Issues & Risks: • A number of specifications and details of the

project need to be decided upon among the other groups within the track.

• Potential of UAV failing with system onboard. • Available Resources:

• Component Lead time • Necessary workspace and equipment. • Required construction materials.

• Imaging System: • Lack of Imaging science knowledge

within the group.

Project # Project Name Project Track Project Family P09561 Visible Spectrum

Imaging System Printing and Imaging Open Architecture,

Open Source Aerial Imaging Systems

Start Term Team Guide Project Sponsor Doc. Revision 2008-2 Ray Ptucha Dr. Carl Salvaggio

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System Architecture

The imaging system has been broken up into the following sub-systems:

• Camera/Camera Interface • Microcontroller • Data Storage • Power • Mounting Frame • Vibration Isolation

The Camera Module and Electronics Module have been separated for ease of switching the camera type as well as to minimize structural interference with the airframe.

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Customer Needs

Need # Importance Description Comments/Status

CN1 1 Low Cost flight time through use on UAV 1 Hour of Flight Time

CN2 2 Robust design Survive Impact

CN3 1 Camera System Modularity (Multiple Spectrum systems) For future projects

CN4 3 Interchangeability of components Batteries and SD Card

CN5 1 Lightweight Meets payload requirements of

UAV B CN6 1 Compact Fits on UAV B CN7 1 Clear Images

CN8 2 Ability to map area with proper image overlap

CN9 2 Autonomous image capture CN10 3 Calibration of system Camera Calibration if possible CN11 2 Flight parameter data GPS, Orientation, Altitude

Engineering Specifications

Engr. Spec. #

Importance Source Specification (description)

Unit of Measure

Marginal Value

Ideal Value

ES1 2 CN11 GPS Location of each image ft ± 20 ± 5

ES2 1 CN1, CN9 Data Storage gigabyte 16 32

ES3 1 CN9 Data Transfer rate Mb/sec 5 40

ES4 1 CN5 Weight lbs 10 5

ES5 1 CN6 Dimensions in 6 x 6 x 8 4 x 4 x 6

ES6 1 CN7

Reduce Vibration above Specified Frequency Hz 50 2

ES7 1 CN3, CN4 Standard Camera Interface

# of types 1 Multiple

ES8 2 CN11 Latency from measurements group ms 10 5

ES9 1 CN1, CN5,

CN6 Power Requirement Volts 15 5

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Vibration Isolation Subsystem Vibration Isolation System Model:

Figure 1: Vibration Isolation System with Coordinate System

Figure 2: Weight Saving Pocket in Base

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Figure 3: Vibration Isolation System

Specifications:

• Material: Aluminum [6061-T6/T6511] and Sorbothane [Durometer 30 oo]

• Dimensions: 4.5” x 5.0” x 3.3”

• Bolt Pattern: 3.75” x 4.25” x ¼-20 thru holes

• Construction: Bolted Connections and Lord 7452 A/B Flexible Urethane Adhesive

• Total Weight: 1.174 lb o Weight of VIS only: 0.889 lb o Camera, Lens, and Mounting Adapter (with screws): 0.285 lb o Maximum weight of Camera, Lens, and Mounting Adapter: 0.467 lb

Description: In order to take clear images while in flight, a vibration isolation system was required to filter out vibrations from the internal combustion engine of the plane, as well as the turbulence during flight. The measurements of GPS position and 3D orientation are being measured on the plane itself, and not on the camera. Since it is crucial that accurate position and orientation data of the camera be measured to allow mosaicing of images, linear guides were used to ensure the orientation of the camera matched the recorded orientation of the plane. This design still allows vibration isolation in the 3 axes while maintaining orientation with the plane.

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Sorbothane was selected as the spring and damper equivalent elastomer for its beneficial frequency dependent properties. As the driving frequency of the system decreases, so does the spring rate. This allows a lower natural frequency than would be possible with a constant spring rate. The damping of the material increases and then decreases as the driving frequency increases. This is fine, since less damping is required to isolate vibration at higher frequencies. Analysis: This subsystem was analyzed as a base excitation problem in 3 distinct axes. The elastomer was approximated using a Kelvin-Voight model, i.e. a spring and damper in parallel, resulting in the following model. In the following model, m is the mass of the object being isolated from vibration, the camera and attached hardware in this case. The mass changes in each of the 3 axes as components of the system are added to handle vibrations in each of the 3 directions. The base is the plane to which the camera is attached, and a sinusoidal vibration of the base with a driving frequency of ωdr is assumed.

Figure 4: Theoretical Model

From this model, the following differential equation was derived.

Equation 1: Base Excitation Model

m

Base

k c

y = Y sin(ωdrt)

x

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In order to solve this equation, the spring rate and damping coefficient for the elastomer must be defined. In an elastomer such as Sorbothane, these properties vary as a function of the driving frequency. From http://www.sorbothane.com/material-properties.php:

Driving Frequency Dynamic Young’s Modulus

η = tan(δ)

5 Hz 90 psi 0.30 15 Hz 135 psi 0.38 30 Hz 186 psi 0.45 50 Hz 246 psi 0.35

Table 1: Dynamic Material Properties of Sorbothane Durometer 30 oo

Figure 5: Curve fit of Dynamic Young’s Modulus for Sorbothane Durometer 30 oo

Figure 6: Curve fit of Loss Factor for Sorbothane Durometer 30 oo

y = 3.28695652x + 80.57608696R² = 0.98838141

0

50

100

150

200

250

0 10 20 30 40 50 60

Youn

g's

Mod

ulus

[psi

]

Frequency [Hz]

Dynamic Young's Modulus

y = -0.00023321x2 + 0.01407256x + 0.23098592R² = 0.98643634

0

0.1

0.2

0.3

0.4

0.5

0 10 20 30 40 50 60

Loss

Fac

tor

Frequency [Hz]

Loss Factor

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Curves were fit to this data to extrapolate data beyond this range of input frequencies.

[psi] Equation 2: Dynamic Young’s Modulus as a Function of Driving Frequency

Equation 3: Loss Factor as a Function of Driving Frequency

These curves fit the data extremely well, with R² values of 0.988 for E* and 0.986 for η. The curve for η goes to zero before reaching higher frequencies, and it was assumed that η would never drop below 0.05, as there should be some damping in the system at any frequency. In this model, the natural frequency, ωn, is defined as follows:

Equation 4: Natural Frequency

The elastomer isolators will be used in shear to further reduce their spring rate and allow for lower natural frequencies, and a greater reduction of vibration at lower frequencies. The spring rate for a material in shear, assuming small deflections, is as follows:

Equation 5: Spring Rate of a Material in Shear

In this case, A is the cross sectional area of the mount where the load is applied, and t is the thickness of the mount. G is the shear modulus and is defined as a function of E and Poisson’s ratio, ν.

Equation 6: Shear Modulus

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Poisson’s ratio for similar polyurethanes is generally 0.25, and this value was assumed to hold true for Sorbothane, as the actual value could not be found. The damping coefficient, c, is defined as a function of the loss coefficient and the spring rate.

Equation 7: Damping Coefficient

The physical model was created in Simulink and the above equations were entered into a Matlab script to calculate the Transmissibility over a range of frequencies, and to determine the natural frequency of the system in each of the 3 axes based on the mass of each subsystem. The elastomer mount selected, measures 0.25” in all directions. Finally, a check on the stresses in the elastomer is required. It will be assumed that each mount is compressed a maximum of 0.020” when installed, and all other loading will come from shear. The elastic modulus at 5 Hz will be used to determine the maximum compressive stress, as this will most closely approximate the static elastic modulus. Also, a maximum acceleration of 3 g will be assumed, and a maximum camera weight will be determined based on the tensile strength of 83.39 psi for Sorbothane Durometer 30 oo.

Equation 8: von Mises Stress

Equation 9: Calculation of Compression Stress

Equation 10: Intermediate Calculation of von Mises Stress

Equation 11: Calculation of Shear Stress

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Equation 12: Determination of Maximum Camera Mass

Results:

Figure 7: Transmissibility of vibrations in the Z-Direction

0 20 40 60 80 100 120 140 160 180 2000

0.5

1

1.5

2

2.5

3

Frequency [Hz]

Tran

smis

sibi

lity

Rat

io

Beneficial above = 30.5 HzNatural Frequency = 16.5 Hz

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Figure 8: Transmissibility of vibrations in the X-Direction

Figure 9: Transmissibility of vibrations in the Y-Direction

0 20 40 60 80 100 120 140 160 180 2000

0.5

1

1.5

2

2.5

3

Frequency [Hz]

Tran

smis

sibi

lity

Rat

io

Beneficial above = 25 HzNatural Frequency = 14 Hz

0 20 40 60 80 100 120 140 160 180 2000

0.5

1

1.5

2

2.5

3

Frequency [Hz]

Tran

smis

sibi

lity

Rat

io

Beneficial above = 21.5 HzNatural Frequency = 12 Hz

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Figure 10: Transmissibility of vibrations in the Y-Direction with Max Camera Mass

Modularity: The design of the VIS allows 0.875 inches of travel of the camera in the Y-Direction, and 1.25 inches of travel in the Z-Direction, allowing cameras of different sizes to be used in this system. The hole cut in the base is 2.5 inches in diameter, allowing cameras with lenses of up to 2.375 inches in diameter to be used without worry of interference during vibrations. As can be seen in the transmissibility diagrams, increasing the mass of the camera and lens has a beneficial effect on the vibration isolation effectiveness of this system. Thus, several different camera systems can be used without modifying the VIS at all. However, it must be kept in mind that the maximum mass of the camera that can be used without changing the elastomer mounts is 0.467 lbm.

0 20 40 60 80 100 120 140 160 180 2000

0.5

1

1.5

2

2.5

3

Frequency [Hz]

Tran

smis

sibi

lity

Rat

io

Beneficial above = 19 HzNatural Frequency = 10.5 Hz

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Imaging System Frame Frame Design:

Specifications:

• Material: Aluminum 6061 1/4” Sheet and Bar Stock

• Dimensions: 4.5” x 3.7” x 7.0”

• Standalone Weight : 0.45 lb

• Construction: Welding

• Mounting: Rubber Mounts, Mounted from top side

The top and bottom faces will be milled from solid sheets of aluminum to increase rigidity and the crossbars will be welded in place to connect the two faces. Removable plastic coverings will cover potentially all of the faces and rubber padding will be added under the boards to help hold them in place. The previous imaging project, P07521: UAV Remote Sensing Imaging System, used a similar design to house their system. The frame itself is very light while still maintaining more than enough strength for the application. Extra space has also been left in the Camera Control section to allow for boards to be added to the microcontroller stack.

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Stress Analysis: Using ANSYS, the frame was first subjected to the loads of the components only. The frame is fixed on the top side at all four corners and on both ends of the middle crossbeam. Analysis was done on the basic frame design as well as the frame with angle support included.

Figure 1: Basic Frame, component loading only.

Figure 2: Frame with corner supports, component loading only.

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As can be seen from the analysis above, the corner supports do in fact reduce the maximum stress, but with only component loading both cases are well below the allowable limit for the material. The greater discrepancy was assumed to come when impulse loading is applied, as would be seen if a crash would occur. The loading is shown below: Fixed at the six points indicated along the top surface. At the front bottom corners are two loads of 100 lbf that resolve into 141.4 lbf load at 45 degrees at each corner. This simulated impact on the front corners is about 40 times the force due to gravity assuming the box weighs 7 lbs. This is applied over a time of 0.01 seconds to simulate impact.

Figure 3: Loading for original frame.

Figure 4: Loading for supported frame

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Results:

Figure 5: Basic Frame with impulse loading over 0.01 seconds

Figure 6: Frame with corner supports with impulse loading over 0.01 seconds. Counter to prior assumptions, the stress in the frame with the corner supports is actually higher than the basic frame.

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The supported frame actually does see a lower stress when subjected to impulse forces that act solely in the Y direction. Yet when subject to forces from the Z direction, it sees higher stress concentrations throughout the frame. Other loads were applied to test each frame’s durability. This included a test with the inertial forces of the components causes by a crash and these proved to have very little effect in comparison to the other stresses in the part.

Frame Type Max Stress (psi) Yield Stress (psi) Factor of Safety

Original 17628 40000 2.269 Corner Supports 20201 40000 1.98

Table 1: Summary of Results Further testing will be done to check that the strength of any welded joints will be sufficient.

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Camera/ Camera Link Subsystem

Camera System Architecture:

Sony XCL-V500 Specifications:

Specification Value Unit Output Image Size 648x494 pixels

Sensitivity 400 @ F5.6 lx Minimum Illumination 1 lx

Frame Rate 60 fps Power requirements 12 VDC Power consumption ≤ 2 Watts

Dimensions 29 x 29 x 30 mm Mass 55 grams

Output data clock 24.55 MHz Operating

temperature 23 - 113 °F Pixel Depth 10 bits

Frame

24 Data

4

Start Image Capture Routine

Camera Link

Sony XCL-V500

Power

12 VDC

Filter

5 VDC

Power

Removable Storage

PC104

Receiver Lens

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Camera Link Specifications: We will be configured for the “Base” configuration – i.e. 28 pin configuration.

Specification Value Unit Data throughput 2.04 Gb/s

# of Pins 28 - Data Pins 24 -

Framing/Enabling Pins 4 -

Serialized 7:1 - Camera Link Modularity: Camera link has a defined set of all functions/commands available. However, not all functions are supported by every camera. A camera file specific to individual cameras should be available from the manufacturer. This file serves to map the standard camera link functions to the camera driver (also supplied by the manufacturer). Assuming only basic functions are used for this project, all that should be required to implement a new camera is the camera driver and camera file. The code will be written using the standard CL functions, which will then map to the specific camera functions. If more uncommon functions/commands are used for different cameras in the future, or a different initialization procedure is required, the code will have to be modified to incorporate these changes. General Purpose Input Since manual image capture in flight is no longer a goal, we have a free input to use as needed. This input still comes from the receiver and can go to either the frame grabber or the PC104. If the signal is input to the PC104, it could be used to start the image capture routine, which would then take a picture at a set frequency. If the input is given to the frame grabber, it can still be used to capture an image remotely.

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Picture taken with Sony XCL-V500

Future Camera Alternatives:

XCL-5005

Ultra-High Resolution 5 Mega Pixel B/W Digital PoCL Video Camera

Standard picture size (H x V) : 2448 x 2050 (5,018,400 pixels) Resolution depth : 8/10/12 bits/pixel Operating temperature 23 to 113 °F (-5 to 45 °C) Power requirements DC 12V Power consumption Max. 3.8 W Weight Approx. 4.6 oz (130 g) Price: $3,595.00 (same for color model)

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XCL-U1000 and XCL-U1000C

CameraLink Color/Black & White Digital Video Camera

Output Image Size 1,600 x 1,200 pixels Power Requirements DC12V Power Consumption 5.5 W or less Dimensions (WxHxD) 44 x 56 x 95 mm (1 3/4 x 2 1/4 x 3 3/4 inches) Mass 250 g (9 oz) Operating Temperature -5 to 45°C (23 to 113°F) Price: $ 3155.00 (same for color model)

• 4008 x 2672 pixels • Color or monochrome • 8, 10, 12 or bits

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JAI AD-080CL

Multi-spectral, prism based 2-channel color and near-IR channels 1024 (h) x 768 (v) active pixels per channel Dimensions (HxWxL): 55 x 55 x 80 mm Storage Constraints Several factors contribute to the storage requirements for any particular flight. Some of these variables can be controlled, while some are inherent to the camera being used. Below are formulas describing the relationship between these variables and the total storage required: For any given camera, the picture size will be:

(KB)

Where, H Res = Horizontal resolution V Res = Vertical Resolution The next contributing factor is how often we are taking pictures, i.e. the picture frequency:

(Hz)

Where, FL = focal length, A = altitude PS = pixel size OL = fractional overlap (.4 = 40%)

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The third and final contributing factor is the length of time that we will be taking pictures. The time in seconds is simply:

The total size then is,

(KB)

Below is a table with varying controllable parameters:

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PC104 / Software Subsection The main idea for the software subsection is that we want it to be modular enough that portions of the code can be worked on and modified independently of one another. To do this we are going to encapsulate functions and variables that are pertinent to a class inside that class so that it is reliant upon itself. We are going to have a software class that is responsible for driving the main program execution and a serial communications class that will handle receiving commands on the serial port. The serial communicator will be on a separate thread than the driver such that the driver is able to be placed into a sleep-like state where it is not performing any work when it is not required to do so. The listener will read the direct serial communications and place that in a new command object before it is put in the queue. When there are items in the queue the driver class will be enabled to decode or handle these commands. Classes and individual objects will be created to handle the control mechanisms for the camera attached via the specific implementation of the FrameGrabber subclass that we are operating in.

+listen() : void+init() : bool-SerialListener() : <unspecified>+instance() : <unspecified>

-_instance : SerialListenerSerialListener

+virtual openShutter()+virtual init()+virtual releaseCamera()+virtual getSetting()+virtual powerOff()+virtual storeIMG()+virtual ~FrameBuffer()

FrameGrabber

+CameraLink()+~CameraLink()

CameraLink

+GigE()+~GigE()

GigE

+handle() : bool+getType() : char+getData()

-Type : char-Data : char

Command

+main()+init() : bool+instance() : <unspecified>-Driver()+~Driver()

-_instance : Driver-driver : Driver-grabber : FrameGrabber-list : CommandList-listener : SerialListener

Driver

+addCommand() : void+nextCommand() : void+getSize() : int

-CElement-Size : int

CommandList

Imaging Software Classes

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User Input?Start Store Input Values to Memory

Check/Wait

Command In Queue?

No

YesYes

Process Command

Yes

Command Type?Shutdown Process ShutdownEnd of Program

Input Error Read Error

Log Error

Interpret Control

Interpret Update Info

ControlShutter?Trigger Shutter

Attempt to Store YesStore

Error?

Store Error

Yes

Log Setting Change Attempt

Update Program Fields

Change Setting

Update Info Field

Log Info

No

Log Picture

No

Info

Read Input

Wait to be Notified No

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User Input?Start Store Input Values to Memory

Check/Wait

Command In Queue?

No

YesYes

Process Command

Yes

Command Type?Shutdown Process ShutdownEnd of Program

Input Error Read Error

Log Error

Interpret Control

Interpret Update Info

Control

Log Setting Change Attempt

Update Program Field

Change Setting

Update Info Field

Log Info

Info

Read Input

Wait to be Notified No

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Power Subsystem: Circuitry and Battery After researching several different kinds of buck converters, the LM25576 – Simple Switcher 42V, 3A Step Down Switching Regulator was chosen for use in taking the supplied battery DC voltage and reducing it to within the required values of voltage and current.

For PC/104 Specifications

Vin 14V Vout 5V Iout 0.94A

Power 4.7W

Blue line = 12V, Orange line = 14V, Green line = 16V

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Schematic

Operating Values

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For the Camera

Specifications Vin 22.2V Vout 12V

Iout (max) 300mA Power 2.0W

Blue line = 12V, Orange line = 14V, Green line = 16V

Schematic

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Operating Values

Battery Specifications Research was also conducted to decide which battery would be appropriate for the project. Originally two options were found, but the dimensions don’t allow for easy loading and unloading from the housing structure.

Capacity (mAh) Current Requirement (max

+ 30%) Life (hours) 3850 300mA 12.83 3850 1170mA 3.29 4200 300mA 14.00 4200 1170mA 3.59

Part Number Voltage (V) Part Required

Input Capacity (mAh) Cells Max Continuous

Discharge TP3850-6SP30 22.2 Camera 12V 3850 6 30C TP3850-4SXV 14.8 PC104 5V 3850 4 25C TP4200-6S2PLB 22.2 Camera 12V input 4200 6 15C TP4200-4S2PL 14.8 PC104 5V input 4200 4 15C

Part Number Size (dimensions in inches) Weight (lbs) TP3850-6SP30 2.13 x 1.78 x 5.67 1.305 TP3850-4SXV 1.19 x 1.78 x 5.67 0.8465 TP4200-6S2PLB 3.08 x 1.34 x 3.94 1.283 TP4200-4S2PL 2.05 x 1.34 x 3.94 0.8334

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Effect of Temperature on Battery

Discharge Rate

Weight versus Life

Weig ht vs . L ife

0

100

200

300

400

500

0 1000 2000 3000 4000 5000

L ife (mA*hours)

Weig ht (g )

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Bill of Materials

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Action Items Dave:

• Analyze the bar size vs. cost, strength, and impact resistance • Determine the location of angle brackets in the structure • Get Airframe B to finalize mounting specs • Talk to Airframe B about heat concerns and a possible heat shield • Determine feasibility of welding

Steve:

• Talk to Kozak to find typical plane movements and vibrations • Look at the spring and damping properties of the materials selected and determine the

output characteristics of the camera • Assess variability with cameras • Find the actual input frequencies • Fairly rigid rubber mounts • Angular displacements may affect camera and picture quality more

Lenny:

• Interface to the GPS • Find an SD card reader to order

o One with an LED that shows safe removal status is preferable • Determine an attack plan to coordinate GPS coordinates with the Image filename • Photos should be uncompressed • Flight time as variable to show changes in storage requirements

Darrell:

• Research PC/104 Interrupts o Internet research o Find sample code o Use 5V trigger pulse from R/C receiver

• Look at I/O ports on PC/104 o Determine Addresses o How to drive a motor or an LED, etc.

• Try to come up with curves to design future of this “track” – overlap, storage requirements, etc.

• Show requirements with 80% overlap and 0% overlap for a good design envelope Jason:

• Take a good picture with the camera o The camera lens may just need to be adjusted o If not, you may need to control the camera via software

• Achieving modulating by having variability in frame grabber

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• Allow for camera to power on usually 30 minutes before stabilization • Calibration of Camera

Joanna:

• Determine whether you are going with 1 battery or 2 o Pros and cons of 1 or 2 battery packs o Ray is concerned that 30V may make your power supplies inefficient

• Graphs that Dr. Hensel wanted, How will temperature of batteries affect life? How long can 12V or 5V be provided?

• Can you implement AC Power on the ground o Only drain from AC power if it is connected o Charge batteries if both are connected

You can use a COTS charger - you don't need to design your own • Quick battery swap (Switch from AC to DC without turning camera off)

o Maybe you can use a daisy-chain cable for this: connect the second battery, unplug the first, and start flying again

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Risks / Risk Mitigation

Risk Severity Probability Risk Level Resolution

Images Blurry High Low Medium Sacrifice orientation wrt plane and isolate system

further.

Accelerations higher than estimated: elastomer fails.

Medium Medium Medium Sacrifice isolation and use larger or stronger mounts.

Tracks have long lead time.

Medium Low Low Order parts as soon as

possible.

Other materials unavailable or have

long lead time. Low Low Low

McMaster-Carr and Grainger can be used

instead of Speedy Metals or Fastenal.

Aluminum cannot be welded

High Low Medium Other fastening means or

outsource construction

Weight climbs above estimated value

Low Medium Medium Keep tight watch on

material use

New Cameras fail to work

High Medium High Thorough testing with

additional cameras

Camera Stops working during flight

Medium Low Medium Camera "endurance" and

repetition test

No way of knowing about in flight failures

Medium Medium Medium

Until 2-way communication is

available, nothing can be done

Threads will not work Low Medium Medium

Run it procedurally without threading, this will

just result in a less efficient program

API Issues Low High Medium

Just going to have to work through them since the

API is for the hardware we have

Magick++ Compilation/Function

issues Medium High High

Unknown software. If we cannot make it work in a

reasonable amount of time find another way to save the pictures. Maybe

look at the source code for the sample program.

38

Risk Severity Probability Risk Level Resolution

GPS Triggering Low Medium Medium

If we are unable to use the GPS trigger it would be possible to generate an

internal clock based on the speed of the PC/104 chip.

PC/104 Stops Working Medium Low Medium

Continue Development on Spare PC/104 Board from

Dr. Hensel. Order New Board if Needed and/or

Time Permits

Camera Link Board Stops Working

High Low Medium

Order New Board, Consider Using on-board Ethernet on PC/104 for

development

GPS data cannot be accessed

Medium Low Medium Complete Project without

GPS implemented

5V Signal from Ground Control Unit Cannot be

used with Interrupts Medium Medium Medium

Implement using polling for initiate sequence.

Investigate if polling will be too processor intensive

to use for program termination.

5V Signal from Ground Control Unit Cannot be

used with Polling Medium Medium Medium

Have program run continuously from take-off

to landing

PC/104 Cannot Store Images to SD Card

High Low Medium Use CF card to store image

data

PC/104 Cannot store multiple images with

GPS data Low Low Low

Use images without GPS data

PC/104 Cannot be programmed to

autonomously capture images

High Low Medium If 5V signal from ground

controller is available, use that to capture images

PC/104 fails to capture/store multiple

images High Low Medium Long hours figuring it out

Plane Crashes with imaging system on-

board High Medium High

Document everything along the way to easily

rebuild the system

Ripple Voltage on Output

Medium Medium Medium Add Filtering Circuitry

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Risk Severity Probability Risk Level Resolution Temperatures Outside

Range for Battery Operation

Medium Medium Medium Temperature Control

Batteries will not recharge correctly

Low Medium Medium Supervise charging of

batteries

Inadequate Power for PC104 and Frame

grabber Medium Medium Medium Testing of actual current

Difficult to swap batteries

Low Low Low Testing of Implementation

40

Senior Design II Plans All:

• Address any action items from the Detailed Design Review. Steve:

• Update EDGE website. • Order raw materials and linear tracks. • Machine parts. • Assemble parts. • Perform preliminary tests with accelerometers. • Complete final testing with image capture.

Dave:

• Order components. • Assemble test joints/Perform strength testing. • Build final frame.

Jason:

• Learn Camera configuration file • Configure Camera to our exact needs (software and camera itself) • Establish common camera interface (software) • Assist Darrell and Lenny with software • Test camera and camera link as per Test Plan

Darrell/Lenny: • Week 1 – Begin writing code to automatically take multiple pictures; investigate

adding SD card reader. • Week 2 – Have code capable of taking multiple pictures autonomously; begin

writing code to run a test flight. Continue development of SD card reader if needed.

• Week 3 – Have code capable of running autonomously; begin writing to code to handle GPS data and Initiate/Terminate sequence from external sources. Continue development of SD card reader if needed.

• Week 4 – Have code for imaging essentially complete, Continue development of SD card reader if needed.

• Week 5 – Test code for imaging; Have SD card reader working. • Week 6 – Begin implementing GPS data acquisition and 5V ground control signal • Week 7 – Finish implementing GPS data acquisition and 5V ground control signal;

begin testing these components. • Week 8 – Perform full unit testing; display at Imagine RIT. • Week 9 – Finalize report and documentation. • Week 10 – Finalize report and documentation.

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Joanna: • Push Through Hole Circuit versus Surface Mount Circuit • Check actual current requirements of PC104 and Camera • Fusing of Power Subsystem • Order parts (IC parts, batteries) • Assemble subsystem • Testing of System

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Test Plan Steve:

• 3 Axis Test using the shaker table in the Mechanical Engineering Department o Use simulated camera weight to avoid damaging camera o Use accelerometers and LabView to record acceleration and compute velocity

and displacement o Use data to verify transmissibility plots o Ensure that accelerations do not exceed the camera’s specifications

• 3 Axis Test using actual camera o Focal length of the Computar M0814-MP lens is 0.1 m (3.937 in) o Focus camera on test pattern o Acquire images during vibration frequency sweep o Determine image clarity

Dave: • Tensile test of welded joint.

• Three point bending test of welded joint.

• Drop test of frame with equivalent component weight. Jason:

• Camera warm-up requirements

• Camera Operating temperatures

• Maximum picture frequency supported (with Darrell and Lenny)

• Swap cameras to ensure modularity

• Pictures quality with varying light, focus, etc

Darrell/Lenny: • Run Simple Program to Take a Picture

• Run a Program to Automatically Take 10 Pictures

• Run a Program to Automatically Take Pictures for approx 1 hour

• Save images to SD Card instead of CF card

• Communicate With GPS

• Store GPS data to memory

• Coordinate GPS data to Relevant Image Taken

• Coordinate GPS data to Relevant Image Taken for Multiple Images

• Automatically take pictures and store GPS data for approx 1 hour

• Set input to PC/104 to 5V, illuminate LED

• Set input to PC/104 to 5V, illuminate LED

• Set input from ground control to PC/104 to 5V, illuminate LED

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• 5V Signal From Ground Control Unit Initiates Picture Taking Sequence From Test 8

• 5V Signal From Ground Control Unit Terminates Picture Taking Sequence From Test 8

• Test operation of the system in both warm and cold temperatures

• Test system when battery power is low

• Test system when batteries are full

• Turn off the power to the system when running or have batteries run out Joanna:

• Testing PC104 and Camera current ratings over time as compared to specifications

• Testing batteries discharge rate

• Testing ease of implementation of batteries into structure

• Testing stability of circuit components

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Appendix

Figure A1: Simulink Model clear all clc nu = 0.25; % no units lg = .25; % in width = .25; % in thk = .25; % in Y = 0.05; % in iso = lg*width*thk*85.5/(12^3); %lbm % For z, x, and y isolators in this order m = [0.47586170, 0.63190052 + iso, 0.81487565 + (2*iso)]; % lbm lg = lg*0.0254; % m width = width*0.0254; % m thk = thk*0.0254; % m m = m*0.45359237; % kg Y = Y*0.0254; % m A = lg*width; % m^2 % IMPORTANT: Properties Extrapolated beyond 50 Hz freq = [2:0.5:60,65:5:200]; % Hz n = length(freq); % Plot assist xx = [0,200]; yy = [1,1]; yyy = [0.5,0.5]; for j = 1:3 for i = 1:n

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f = freq(i); wdr = f*2*pi; % rad/s % Duro 30 oo Estar(i) = 3.2869565*f + 80.57608696; % psi Estar(i) = Estar(i)*6894.759086775369; % Pa Gstar(i) = Estar(i)/(2*(1 + nu)); % Pa eta(i) = -0.00023321*f^2 + 0.01407256*f + 0.23098592; % no units if eta(i) < 0.05 eta(i) = 0.05; end % Shear k(i) = Gstar(i)*A/thk; % N/m c(i) = eta(i)*k(i)/wdr; % N-s/m zeta(i) = c(i)/(2*sqrt(m(j)*k(i))); % no units c1 = c(i)*Y*wdr/m(j); c2 = k(i)*Y/m(j); c3 = -c(i)/m(j); c4 = -k(i)/m(j); sim('vibes3'); X = max(x); T(j,i) = X/Y; end xTrue(j) = find(T(j,:)<1, 1); natf(j) = find(T(j,:)==max(T(j,:))); figure(j) plot(freq,T(j,:),'-b',xx,yy,'-r',xx,yyy,'-g'); xlabel('Frequency [Hz]'); ylabel('Transmissibility Ratio'); title({['Beneficial above = ', num2str(freq(xTrue(j))), ' Hz']; ['Natural Frequency = ', num2str(freq(natf(j))), ' Hz']}); end

Code A1: Matlab Code to Determine Transmissibility