drexel rocksat
DESCRIPTION
Drexel RockSAT. Preliminary Design Review. Kelly Collett • Christopher Elko • Danielle Jacobson October 26, 2011. PDR Presentation Contents. Section 1: Mission Overview Mission Statement Mission Requirements Mission Overview Theory and Concepts Literature Review Concept of Operations - PowerPoint PPT PresentationTRANSCRIPT
Drexel RockSAT Preliminary Design Review
Kelly Collett • Christopher Elko • Danielle JacobsonOctober 26, 2011
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PDR Presentation Contents• Section 1: Mission Overview
• Mission Statement• Mission Requirements• Mission Overview• Theory and Concepts• Literature Review• Concept of Operations• Expected Results
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PDR Presentation Contents• Section 2: System Overview
• Physical Model• Critical Interfaces• Requirement Verification• User Guide Compliance
• Section 3: Subsystem Design• Energy Harvesting Subsystem• Structural Subsystem• Electrical Subsystem• Visual Verification Subsystem
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PDR Presentation Contents• Section 4: Prototyping Plan
• Projected Prototyping Process• Prototype Risk Assessment
• Section 5: Project Management Plan• Organizational Chart• Schedule• Budget• Work Breakdown Schedule• Sharing Logistics
Mission OverviewDrexel RockSat Team 2011-2012
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Mission Statement
Develop and test a system that will use piezoelectric materials to convert
mechanical vibrational energy into electrical energy to trickle charge on-board power
systems.
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Mission RequirementsNumber Requirement
MIS-REQ-1000 Must be able to convert vibrational energy to electrical energy
MIS-REQ-2000 Must be able to withstand launch environments
MIS-REQ-3000 Final design must meet RockSAT specifications
MIS-REQ-4000 Must be functional during flight
MIS-REQ-5000 Must not interfere with canister partner’s design
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Mission Overview• Demonstrate feasibility of power generation
via piezoelectric effect under Terrier-Orion flight conditions
• Determine optimal piezoelectric material for energy conversion in this application
• Classify relationships between orientation of piezoelectric actuators and output voltage
• Data will benefit future RockSAT and CubeSAT missions as a potential source of power
• Data will be used for feasibility study
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Theory and Concepts• Piezoelectric Material
substance with linear electromechanical interaction between mechanical and electrical states in crystalline materials
• Piezoelectric Effectelectrical potential (voltage) developed within a piezoelectric material in response to an applied pressure or stress.
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Theory and Concepts continued
Where D is electric displacement, ε is permittivity,and E is electric field strength
Where S is mechanical strain, s is compliance,and T is mechanical stress
Superscript e denotes a zero/constant electric field;Superscript t denotes a zero/constant stress field;
d indicates piezoelectric constants
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Theory and Concepts continued
• Bonded to cantilevered aluminum strips with mass attached to free end
• Dynamic deflection under vibration andg-loading will create voltage potential
• Array of piezoelectric actuators
• Various orientations will account for vibrations in multiple directions http://en.wikipedia.org/wiki/Euler-
Bernoulli_beam_equation
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Theory and Concepts continued
• Place mass at end of beam to achieve maximum deflection under vibration
• Model with point load
Top: Bending Moment, M(x)Middle: Shear Force, Q(x)Bottom: Deflection, δ(x)
http://en.wikipedia.org/wiki/Euler-Bernoulli_beam_equation
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Theory and Concepts continued
• Uniform, distributed load when subjected to g-forces during launch
• Model with load acting along length of beam
Top: Bending Moment, M(x)Middle: Shear Force, Q(x)Bottom: Deflection, δ(x)
http://en.wikipedia.org/wiki/Euler-Bernoulli_beam_equation
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Theory and Concepts continued
• Electric potential (voltage) developed throughout piezoelectric actuators in AC form• AC voltage conditioned
using a full-bridge rectifier• Accumulated in a
capacitor• Monitored using a
voltmeter• Recorded using data
acquisition system (DAQ)http://en.wikipedia.org/wiki/Diode_bridge
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Literature ReviewPiezoelectric Generator Harvesting Bike
Vibrations Energy to Supply Portable Devices
E. Minazara, D. Vasic, and F. Costa• Piezoelectric generator that
harvests mechanical vibration energy and produces electricity
• Determined optimal band to harvest energy 12.5Hz• Modeled piezoelectric beam as spring mass damper
system• Produced ~3.5mW electricity
capable of powering LED
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Literature Review continued
Recent Progress in Piezoelectric Conversion and Energy Harvesting Using Nonlinear Electronic Interfaces and Issues in Small Scale Implementation
D. Guyomar and M. Lallart• Design of an efficient microgenerator must consider:
• Maximization of input energy• Maximization of electromechanical energy• Optimization of energy transfer
• Increase conversion abilities by:• Increase voltage• Reduce time shift between speed and voltage• Increase coupling term
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Literature Review continued
A Review of Power Harvesting Using Piezoelectric Materials
S. R. Anton and H. A. Sodano• PZT widely used
• Extremely brittle• Piezoceramics prone to fatigue crack growth when
subjected to high-frequency cyclic loading• PVDF exhibits considerable flexibility
• Flexible materials more beneficial• Practical coupling modes
• -31: Force applied perpendicular to poling direction• -33: Force applied in same direction as poling
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Literature Review continued
A Review of Power Harvesting Using Piezoelectric Materials
S. R. Anton and H. A. Sodano• High power output situations
• Stack configurations most durable in high-force environments
• When driving frequency is at resonant frequency of the system
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Literature Review continued
Comparison of Piezoelectric Energy Harvesting Devices for Recharging Batteries
H. A. Sodano and D. J. Inman• Researchers tested energy-harvesting qualities of
three different piezoelectric materials• Lead-zirconate-titanate (PZT)• Quick Pack bimorph actuator material (QP)• Macro Fiber Composite (MFC)
• Measured vibration of compressor, using piezo samples as accelerometers – output in volts• Full-bridge rectifiers used to condition signal from
oscillating AC into DC to charge batteries
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Literature Review continued
Comparison of Piezoelectric Energy Harvesting Devices for Recharging Batteries
H. A. Sodano and D. J. Inman• Efficiencies varied by material
• QP most effective for resonant frequencies (~8 to 9%)• PZT most effective for random vibrations (~4 to 4.5%)• MFC significantly less effective than PZT and QP
• Low-current, high-voltage output lacks the strength to charge batteries and is easily dissipated by diodes in circuit
• QP charged batteries fastest under resonant frequencies; PZT charged the best with random vibration.
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Literature Review continued
Piezoelectric Sea Power GeneratorR. M. Dickson• Operating principle
• Attempted to harness mechanical energy of waves as changes in pressure acting upon piezoelectric mats
• Minimally intrusive to ecosystem• Important implications for this project
• Studies show that static pressure alone does not induce a charge in piezoelectric materials
• Piezo arrays must be continuously deformed to create an electric potential that can be harvested
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Concept of Operations• G-switch will trip upon launch, activating all
onboard power systems• Batteries power Arduino microprocessor and data
storage unit• Data collection begins
• Vibration and g-loads on piezo arrays create electric potential registered on voltmeter• Current conditioned to DC through full-bridge
rectifier and run to voltmeter• Voltmeter output recorded to internal memory• Data gathered throughout duration of flight
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Concept of Operations• Data acquisition and storage will enable
researchers to monitor input from multiple sources• XY-plane vibrational energy• Z-axis vibrational energy
• Researchers will determine if amount of power generated is sufficient for the power demands of other satellites
• Include visual verification of functionality• Use energy from piezo arrays to power small LED• Onboard digital camera will verify LED illumination
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Expected Results• Piezoelectric beam array will harness enough
vibrational energy to generate and store voltage sufficient to power satellite systems
• Success dependent on following factors:• Permittivity of piezoelectric material• Mechanical stress, which is related to the
amplitude of vibrations• Frequency of vibrations
System OverviewChristopher Elko
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Physical ModelMicrocontroller
Power Supply
Accelerometers
Piezo Arrays
Camera
Verification LED
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Subsystem IdentificationEPS – Electrical Power Subsystem
• Includes Arduino microprocessor, g-switch, accelerometers, voltmeter, battery power supply, and all related wiring
STR – Structural Subsystem• Includes Rocksat-C decks and support columns
PEA – Piezoelectric Array Subsystem• Includes piezoelectric bimorph actuators, cantilever
strips, mounting system, rectifier, and related wiring
VVS – Visual Verification Subsystem• Includes digital camera, LED, and all related wiring
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Critical InterfacesInterface Name Brief Description Potential Solution
EPS-STRThe electrical power system boards will need to mount to the RockSat-C deck to fix them rigidly to the launch vehicle. The connection should be sufficient to survive 20Gs in the thrust axis and 10 Gs in the lateral axes. Buckling is a key failure mode.
Past experiences show that stainless steel or aluminum stand-offs work well. Sizes and numbers required will be determined by CDR.
STR-PEAThe piezoelectric bimorph actuators must integrate into the structure without introducing a hazard to the operations of other satellite operation. The structure must also be designed such that the oscillatory motions of the piezo array cantilevers will not be impeded. Fracture is a key failure mode.
Testing will verify mounting methods and loading limitations of piezo actuators. Testing will also determine ideal range of deformation for maximum power generation.
PEA-EPSThe piezoelectric actuators must be wired correctly to ensure a voltage signal reaches the voltmeter and is registered by the DAQ.
AC signal may need to be conditioned to DC with a rectifier and amassed using an inline capacitor. Testing will verify whether parallel or series wiring should be used.
VVS-STRThe components (camera, LED) of the visual verification system must be mounted to the RockSat-C deck to fix them rigidly to the launch vehicle. The connection should be sufficient to survive 20Gs in the thrust axis and 10 Gs in the lateral axes.
Utilize stainless steel or aluminum standoffs, as in EPS-STR interface above.
VVS-PEA The LED component of the visual verification system must illuminate when a voltage is generated by the piezo arrays.
Wire LED in series with PEA to ensure proper illumination.
EPS-VVSThe camera component of the visual verification system must be powered from a steady, reliable source. Camera data must also be stored for playback after the flight.
Power camera from same battery source as microprocessor.
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Requirement VerificationRequirement Description Verification Method
The full system shall fit in the allotted space within the canister. Visual inspection will verify this requirement. Inspection
The system shall survive the vibration characteristics prescribed by the RockSAT-C program.
The system will be subjected to these vibration loads during preliminary testing on an associated institution’s vibration table, as well as in June during testing week.
Test
The power supply shall be engaged via the g-switch and all electronic systems powered on upon launch.
The minimum load needed to activate the g-switch and engage electronic systems will be calculated to ensure proper functionality under launch conditions.
Analysis
The piezoelectric actuators shall develop a recordable level of electric potential.
Preliminary testing will ensure a potential is developed when bimorph piezoelectric actuators are deformed.
Test
The microprocessor shall record and store all voltage, current, and visual data for duration of flight.
Arduino microprocessor will be programmed and checked to ensure proper collection of flight data prior to testing.
Demonstration
The camera shall record all activity the LED experiences.
The camera will be checked for functionality and successful integration into electrical system prior to testing.
Demonstration
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User’s Guide Compliance• Magnitude of mass to be determined by CDR• CG – to be determined based on design,
dictated by pre-CDR testing and validation• Low voltage electrical components used• No ports required
Subsystem DesignStructural Subsystem
Christopher Elko
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Structural ComponentsRigid Mounting Deck Support Column
Subsystem DesignEnergy Harvesting Subsystem
Christopher Elko
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Piezoelectric Actuators
Aluminum Cantilever
Mass
FastenerPiezoelectric Strip
Support Block
Redundant Assembly for Multi-plane Vibration
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Piezoelectric ActuatorsMounted to Lower Deck Attached with Fastener
Subsystem DesignElectrical Power Subsystem
Danielle Jacobson
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Block DiagramPiezoelectric
Power OutputLED
Arduino Microcontroller
Camera
Power Supply
Rectifier
Piezoelectric Power Output LED
Rectifier
High-G Accelerometer
High-G Accelerometer
Low-G Accelerometer
Low-G Accelerometer
G-Switch
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Microcontroller• Arduino ATMEGA328 Microprocessor (Open
Source)• Record and store data on 2GB SD card
• Vibration data from accelerometers• Voltage output from piezoelectric materials
• Powered by four (4) AA replaceable batteriesOperating Voltage 5V
Input Voltage 6-20V
Digital I/O Pins 14 (6 can provide PWM output)
Analog Input Pins 6
DC Current per I/O Pin 40mA
DC Current for 3.3V Pin 50mA
Flash Memory 32KB 0.5KB used by boot loader
SRAM 2KB
EEPROM 1KB
Clock Speed 16MHz
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Accelerometers• Two (2) Low-G Accelerometers
• Analog Devices ADXL206 Dual-Axis• Two (2) High-G Accelerometers
• Analog Devices ADXL278 Dual-AxisLow-G Accelerometer High-G Accelerometer
Range +/- 5g +/- 35gSensitivity 312 mV/g 27mV/gOutput Type Analog Analog
Noise Density 110 µg/rtHz 180 µg/rtHzTemperature Range -40°C to 175°C -40°C to 105°CSize 13mm x 8mm x 2mm 5mm x 5mm x 2mm
Operating Voltage 4.25-5.25 V 4.25-5.25 V
Power 700 µV at VS=5V 2.2mA at Vs=5V
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Bridge Rectifier and G-Switch
• Bridge Rectifiers• Four (4) Diode Schottky 1A 20V MBS-1
• G-Switch• One (1) Omron Basic Roll Lever Switch SS-5GL2
Speed Recovery ≤ 500ns
Current 1 Amp
Voltage 20V Max at Peak Reverse
Temperature Range -55°C to 150°C
Operating Force 50 gf
Contact Rating 5A @ 125 VAC
Voltage 20V Max at Peak Reverse
Temperature Range -25°C to 85°C
Weight 1.6 g
Subsystem DesignVisual Verification Subsystem
Kelly Collett
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Block Diagram
Piezoelectric Wire Output
LED
EPS Power Supply
Camera
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Camera Specifications• Runs on 12VDC, 100mA• Size: 0.98” sq. x 0.8”
IMAGING SPECIFICATIONSImager Manufacturer SonyLines 420Lux 0.0003
LENS SPECIFICATIONSMax FOV (degrees) 72Pinhole Yes
POWER REQUIREMENTSAmps DC (mA) 100Power Supply Included NoVolts DC Input 12
http://www.supercircuits.com/Security-Cameras/Micro-Video-Cameras/PC180XP2
Super B/W Microvideo Pinhole Camera
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LED Specifications• 5mm through-hole LED• 360-degree viewing angle• Low power consumption
http://www.superbrightleds.com/moreinfo/component-leds/5mm-white-led-360-degree-viewing-angle-4500-millilumens/341/1288
White 5mm LED
General Specifications
Lumen 4.5
Viewing Angle 360 deg
Wattage Consumption 0.064 W
Color Cool White
Color Temperature 7350 K
Prototyping PlanChristopher Elko
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Prototyping Plan• STR
• Structural Subsystem will be designed and analyzed primarily using CAD and FEM techniques
• Prototype to be constructed and tested for fitment and mounting methods
• PEA• Piezoelectric actuators will be tested to determine
deformation limits and optimal deformation for energy harvesting
• Mounting/bonding methods to be explored upon construction of first prototypes
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Prototyping Plan continued
• EPS• Electronic interfaces will be table-tested with breadboard
and reconfigurable components• Testing will help to determine system capabilities
• VVS• Testing will help to determine system capabilities and
effects on other subsystems
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Prototype Risk Assessment
EPSFunctionality of
microcontroller must be verified by CDR
Prototype controller on bread board to verify
function
PEABond between PE
actuators and aluminum must not fail
Test various bonding materials and application
methods
STRConcerns exist about
clearance andcomponent mounting
Prototype all interfaces with STR to ensure
integrity
Risk/Concern ActionSubsystem
VVSLED must light, camera must not fail to record
actions of LED
Test LED with PEA toverify power draw;
test camera to ensure functionality
Project Management PlanKelly Collett
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Organizational Chart
Danielle JacobsonElectrical Systems Lead
Machining
Christopher ElkoStructural Lead
CAD Designer
Kelly CollettVisual Verification Lead
Testing
Drexel SpaceSystems LabProject Support
Dr. Jin KangFaculty Advisor
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ScheduleNovember 201111/3
Order partsPiezo samples, electronics, structural materials
11/7PDR due
11/14Senior Design Written Proposal dueBegin Testing Samples (vibe, electronics)
11/17Senior Design Proposal Presentation
11/21Online Progress Report due
RockSat Deadlines • Drexel Deadlines
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Schedule continued
December 2011 – January 2012Continue testing and verification of all structures andparts for use in proposed assembly• Order additional parts as needed• Make necessary modifications12/8
CDR due1/9
Flights Awarded1/30
Online Progress Report due
Schedule continued
FebruaryContinue testing and integration2/6 – Midterm Draft Report due2/13 – Subsystem Testing Reports due2/27 – Progress Presentation to Faculty Advisor
MarchContinue testing and integration3/12 – Online Progress Report due3/19 – Project Progress Report due
April3/9 – Senior Design Project Abstract due4/15 – Payload Canister ReceivedIntegration of components with canister
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Estimated Spring Schedule
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Schedule continued
April, continuedFirst Full Mission Testing (vibration, etc.)4/23 – First Full Mission Simulation Test Report
Presentation dueMay
Continue Full Mission Testing and modificationsWeekly teleconferences5/14 – Final Senior Design Project Report due5/21 – Final Project Presentation5/28 – Launch Readiness Review (LRR) Presentation due5/30 – College of Engineering Project Competition
JuneWallops
Estimated Spring Schedule, continued
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Budget• Spending to date: $94.44• Estimated final total: $673.93
• Major Cost Contributors• Digital Camera - $109.99• Piezoelectric Components - $150
• Major Time Contributors• Piezoelectric Components – 7-10 days• Accelerometers – 7-10 days
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Budget continued
Item Subsystem Supplier Cost Lead Time
12"x12“Polycarbonate Sheet STR McMaster-Carr $7.23 1 day
+/- 35g Accelerometer EPS DigiKey $17.23 7-10 days
+/- 3g Accelerometer EPS DigiKey 7-10 days
G-Switch EPS DigiKey $2.15 7-10 days
Arduino ATmega 128 microprocessor EPS 7-10 days
Bridge rectifier EPS DigiKey 0.62 7-10 days
Piezo Electric Parallel Bimorph Actuator PEA Steminc $19.98/set of 2 7-10 days
Digital Camera VVS Super Circuits $109.99 3-5 days
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Budget continued
Item Subsystem Supplier Cost Lead Time
LED Lights VVS SuperbrightLEDs.com $1.59 3-5 days
TBD PIEZO MAT'L PEA – testing TBD $75 TBD
TBD PIEZO MAT'L PEA – testing TBD $75 TBD
TBD PIEZO MAT'L PEA – final installation TBD $150 TBD
TBD CIRCUITRY COMPONENTS EPS – testing TBD [DigiKey] $50 TBD
TBD CIRCUITRY COMPONENTS EPS – final installation TBD [DigiKey] $50 TBD
1/8" x 1" Rectangular Aluminum Stock STR McMaster-Carr $17.91 1 day
TBD STRUCTURAL MATERIALS STR TBD [McMaster] $50 TBD
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Sharing LogisticsTemple University• Plan for Collaboration
• Email, phone, campus visits• Full model designed in
SolidWorks for fit check• DropBox/Google Docs for
file sharing• Structural interface
• Consider clearance• Joining method
ConclusionsWhat’s Next?
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Next Steps• Conduct functionality tests of
subsystems• PEA material strength testing• EPS functionality test
• Determine final materials to be used• Procure parts and begin assembly• Fabricate structures for assembly
Thank you!Questions?