Transcript spacegrant.colorado.edu

Critical Design Review
PDR Presentation Contents
•
Section 1: Mission Overview
• Mission Statement
• Mission Requirements
• Mission Overview
• Concept of Operations
• Expected Results
2
PDR Presentation Contents
•
Section 2: Design Description
•
•
•
•
Off-ramps
Physical Model
Mechanical Design
Electrical and Software Design
• Section 3: Prototyping and Analysis
•
•
•
•
Mechanical Subsystems
Electrical Subsystems
Mass Budget
Power Budget
3
PDR Presentation Contents
•
Section 4: Manufacturing Plan
• Mechanical Elements
• Electrical and Software Elements
• Section 5: Testing Plan
• PEA Subsystem
• EPS Subsystem
• VVS Subsystem
• Total System Testing
4
PDR Presentation Contents
•
Section 6: Prototype Risk Assessment
• PDR Risk Walk-down
• Top CDR Risks
• Section 7: User’s Guide Compliance
• Section 8: Project Management
•
•
•
•
Organizational Chart
Schedule
Budget
Sharing Logistics
5
Drexel RockSat Team 2011-2012
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.
7
Mission Requirements
Number
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
8
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
9
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
10
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
11
Expected Results
• Piezoelectric beam array will harness enough
vibrational energy to generate and store
voltage sufficient to power satellite systems
• Anticipate output of 130 mV per piezo strip,
based on preliminary testing.
• Success dependent on following factors:
• Permittivity of piezoelectric material
• Mechanical stress, which is related to the
amplitude of vibrations
• Frequency of vibrations
12
Christopher Elko
Subsystem Identification
EPS – 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
14
Off-Ramps VVS
• Main concern: Camera activation
• Relaying the camera to the g-switch for
activation after launch will likely prove difficult.
• If this cannot be achieved on time, the VVS will
be removed from the payload.
•
This will drop the mass of the payload
significantly, and will require additional ballast in
its place.
15
Physical Model
Accelerometer Array
Microcontroller
Power
Supply
G-Switch
Bridge
Rectifiers
Flight
Decks
Camera
Standoff
Supports
Piezo Arrays
Verification LED
16
Canister Fitment
Canister Partner’s
Space Allowance
10.0”
4.313”
17
Mechanical Design STR
Stainless Fasteners
Clear Acrylic
Flight Decks
8-32 thread
x 3/8” long
QTY = 10
¼” thick
9.29” dia.
QTY = 2
Aluminum
Standoffs
5/16” hex
x 2 ¼” long
QTY = 5
Fifth standoff column
included to provide
support for EPS
electronics mounted
to top deck.
18
Mechanical Design PEA
Piezoelectric Strip
PZT Ceramic
40 mm x 10 mm
5 mm thick
Fasteners
Support
Block
Aluminum Cantilever
2 ¼” x ½”
0.040” thick
Different orientations
account for vibrations in
multiple planes.
19
PEA Design continued
Mounted to Lower Deck
Use 4-40 x 3/8” Screws
20
Electrical Design
LED
High-G
Accelerometer
High-G
Accelerometer
Piezoelectric
Power Output
Piezoelectric
Power Output
Rectifier
Rectifier
Arduino
Microcontroller
G-Switch
LED
Camera
Low-G
Accelerometer
Low-G
Accelerometer
Power
Supply
21
Electrical Design continued
Piezoelectric
Wire Output
LED
EPS
Camera
Power
Supply
22
Electrical Elements
•
•
•
Powered by 4 AA batteries
Connects directly to
microcontroller
Modified to incorporate
G-switch
G-Switch
To Bridge Rectifier
Piezo Arrays
(Battery)
LED
Battery
Pack
Microcontroller
To Bridge Rectifier
PEA-VVS Circuit Diagram
G-switch interface with EPS
23
Electrical Elements continued
Low-G Accelerometer
High-G Accelerometer
24
Electrical Elements continued
Bridge Rectifier #1
Piezo
Array 1
Bridge Rectifier #2
Piezo
Array 2
25
Electrical Elements continued
• Breadboard used for SD card and Arduino
microcontroller integration
http://www.electronicslab.com/blog/?m=200806
26
Electrical Elements continued
• Two breadboards
•
•
LED circuit
SD card integration
• Allowance of 15-20 iterations to debug electronics
•
Limited previous exposure to programming
microcontrollers and EE in general
• All electrical elements have been procured
• Four dual-axis accelerometers have been
replaced with two three-axis accelerometers
27
Software Elements
28
Software Elements continued
Input
Output
Purpose
G-Switch T/F
True/False
Write to SD when T
Accelerometer 1 X
Data Collection
Accelerometer 1 Y
Data Collection
Accelerometer 1 Z
Accelerometer 2 X
Accelerometer 2 Y
Accelerometer 2 Z
Voltage Outputs
All data output to SD card
via “write to file”
command
Data Collection
Data Collection
Data Collection
Data Collection
Bridge Rectifier 1
Data Collection
Bridge Rectifier 2
Data Collection
Time (>1000s?)
True/False
End write command when T
29
Accelerometer Pseudo-Code
*/
// these constants describe the pins. They won't
change:
const int groundpin = 18;
// analog input pin
4 -- ground
const int powerpin = 19;
// analog input pin
5 -- voltage
const int xpin = A3;
// x-axis of the
accelerometer
const int ypin = A2;
// y-axis
const int zpin = A1;
// z-axis (only on 3axis models)
void setup()
{
// initialize the serial communications:
Serial.begin(9600);
// Provide ground and power by using the analog
inputs as normal
// digital pins. This makes it possible to directly connect the
// breakout board to the Arduino. If you use the normal 5V
and
// GND pins on the Arduino, you can remove these lines.
pinMode(groundpin, OUTPUT);
pinMode(powerpin, OUTPUT);
digitalWrite(groundpin, LOW);
digitalWrite(powerpin, HIGH);
}
void loop()
{
// print the sensor values:
Serial.print(analogRead(xpin));
// print a tab between values:
Serial.print("\t");
Serial.print(analogRead(ypin));
// print a tab between values:
Serial.print("\t");
Serial.print(analogRead(zpin));
Serial.println();
// delay before next reading:
delay(100);
30
SD Card Data Storage Code: Complete
#include <sd-reader_config.h>
#include <sd_raw.h>
#include <sd_raw_config.h>
int print_disk_info();
int sample();
int readDisk();
byte incomingByte;
void printWelcome();
long int address;
byte tempBytes[2];
void setup()
{ Serial.begin(9600);
delay(1000);
printWelcome();
if(!sd_raw_init())
{ Serial.println("MMC/SD initialization failed");
} print_disk_info();
}void loop()
{ int i;
if(Serial.available()>0)
{incomingByte=Serial.read();
switch(incomingByte)
{ case 114:
readDisk();
break;
case 115:
sample();
break;
default:
break;}}
int sample()
{ int i,j;
int temp;
byte low;
byte high;
byte inByte;
Serial.println();
Serial.println();
Serial.println("Sampling..");
for(i=0;i<500;i=i+2)
{ if(Serial.available()>0)
{inByte=Serial.read();
if(inByte==113) return 0;}
temp=analogRead(0);
Serial.print(temp,DEC);
Serial.print(" ");
//Convert int to 2 bytes
low=temp&0xFF;
high=temp>>8;
// Serial.print(temp,DEC);
//Serial.print(low,DEC);
//Serial.print(high,DEC);
tempBytes[0]=low;
tempBytes[1]=high;
if(!sd_raw_write(i,tempBytes,2))
{ Serial.print("Write error");
} //sd_raw_sync();
delay(5000);
Serial.println(); }
return 1;}
int readDisk()
{ byte low;
byte high;
byte info[2];
int i;
int result;
Serial.println();
for(i=0;i<50;i=i+2)
{sd_raw_read(i,info,2);
//Serial.print(info[0],DEC);
//Serial.print(" ");
//Serial.print(info[1],DEC);
low=info[0];
high=info[1];
result=high<<8;
//result<<8;
Serial.print(" ");
Serial.print(result+low,DEC);
Serial.print(" ");}}
void printWelcome()
int print_disk_info()
{ Serial.println("------------------------");
Serial.println("Data sampling system");
Serial.println("send r to read disk");
Serial.println("send s to start sampling");
Serial.println("send q to stop sampling");
Serial.println("Ready.....");
Serial.println("-------------------------");}
{
struct sd_raw_info disk_info;
if(!sd_raw_get_info(&disk_info))
{ return 0; }
Serial.println();
Serial.print("rev: ");
Serial.print(disk_info.revision,HEX);
Serial.println();
Serial.print("serial: 0x");
Serial.print(disk_info.serial,HEX);
Serial.println();
Serial.print("date: ");
Serial.print(disk_info.manufacturing_month,DEC);
Serial.println();
Serial.print(disk_info.manufacturing_year,DEC);
Serial.println();
Serial.print("size: ");
Serial.print(disk_info.capacity,DEC);
{Serial.println();
Serial.print("copy: ");
Serial.print(disk_info.flag_copy,DEC);
Serial.println();
Serial.print("wr.pr.: ");
Serial.print(disk_info.flag_write_protect_temp,DEC);
Serial.print('/');
Serial.print(disk_info.flag_write_protect,DEC);
Serial.println();
Serial.print("format: ");
Serial.print(disk_info.format,DEC);
Serial.println();
Serial.print("free: ");
return 1;}
31
Christopher Elko
Prototyping
PEA
•
Preliminary test setup measured voltage levels from
a single strip actuator under deformation using a
digital voltmeter.
•
•
•
Results suggest adequate voltage potential for entire
system, with an average of approximately 132 mVAC
generated by a single actuator.
Preliminary finite element analysis results in ABAQUS
suggest aluminum is adequate for resistance to
cyclic loading in this application.
Mechanical analysis, in conjunction with destructive
testing of piezo actuators, will optimize dimensions of
support cantilever dimensions.
33
Prototyping continued
STR
•
•
Preliminary FEA results suggest a fifth aluminum
standoff is desirable for added support of electronic
components on upper deck.
Currently finalizing design and interactions with PEA
mounting methods.
EPS
•
•
SD card adapter to be integrated
Accelerometers integrated into microcontroller and
tested for data output
VVS
•
Tested LED circuit for functional interaction with PEA
34
Prototyping continued
Preliminary piezo strip
actuator voltage testing
for PEA design
Preliminary piezo strip
actuator LED testing for
PEA-VVS interaction
35
Analysis cantilever deflection
Point Load
•
•
Distributed Load
Maximum deformation at end of beam, where x = L
Combined loading
during flight due to
G-loading and mass
at end of beam
36
Analysis FEA
PEA
Stress Analysis
•
•
•
Point load
to simulate
mass at end
Uniform load
to simulate
G-loading
Maximum
stress does
not exceed
2000 psi
37
Analysis FEA
PEA
Deformation Analysis
•
•
•
Point load
to simulate
mass at end
Uniform load
to simulate
G-loading
Maximum
deformation:
0.3 inches
38
Analysis FEA
STR
Stress Analysis
•
•
•
Point load
at electronic
elements
Uniform load
to simulate
G-loading
Maximum
stress does
not exceed
649.6 psi
39
Analysis FEA
STR
Deformation Analysis
•
•
•
Point load
at electronic
elements
Uniform load
to simulate
G-loading
Maximum
deformation:
0.92 inches
40
Mass Budget
Part
Mass (lbf)
Qty
Subtotal (lbf)
Comment
Flight Deck
0.84
2
1.68
Aluminum Standoff
0.02
5
0.1
Piezoelectric Arrays
0.01
4
0.04
G-Swtich
0.014
1
0.014
Microprocessor
0.089
1
0.089
Bridge Rectifier
0.012
2
0.024
Accelerometers
0.002
2
0.004
AA Battery
0.0178
4
.0712
Includes battery holder
LED
N/A
1
0
Negligible weight
Camera
0.0691
1
0.0691
Based on micro-camera, may change manufacturer
STR
PEA
Includes actuator, cantilever, mounting block, fastener,
and deflection limiter
EPS
VVS
TOTAL
2.091
41
Power Budget
Part
Voltage (V)
Current (A)
Qty
Time On (min)
Amp-hours
Structure
0
0
0
10
0
PiezoElectric Actuators
0.13 V
-
4
10
0
G-Swtich
250VAC
5.00E+00
1
0.02
1.39E-03
Microprocessor
5V
4.00E-02
54
10
3.60E-01
Bridge Rectifier
20
1.00E+00
2
10
3.33E-01
Accelerometers
2.2-16 V
5.00E-04
2
10
1.67E-04
0.055 V
5.00E-05
2
10
1.67E-05
Comment
STR
PEA
power generation part of project scope
EPS
VVS
LED
Camera
10
TOTAL
Self-Contained
0.69
42
Choose your weapon
Mechanical Elements
STR
•
•
Acrylic plate laser-cut to size/shape of flight decks
Flight decks among first components manufactured
to ensure proper interaction with other subsystems
PEA
•
•
•
Cantilevers cut to size from sheet aluminum upon
determining optimum
Piezo actuators to be bonded to cantilevers
Mounting blocks and deflection limiters must be
custom-milled from aluminum stock
44
Electrical Elements
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
45
Software Elements
Code to be finalized
• Accelerometers
• Voltage output from bridge rectifiers
• SD card data recording
Code to be developed
• Power loop for camera
• G-switch
Code block dependencies
• SD card code integrates all subroutines
• All code dependent on “true” output from G-switch
46
Choose wisely.
PEA Subsystem
Piezo Actuator Tests
Non-destructive Testing
• Non-destructive testing
will determine voltage
output from piezo
actuators.
• Test Plan
• Connect actuators to
voltmeter, LEDs; flex
Destructive Testing
• Will determine bending
deformation limits of
piezo actuators.
• Test Plan
• Use spindle micrometer to
bend piezos until fracture.
actuators to generate
current
48
PEA Subsystem continued
Cantilever Tests
Unrestricted Cantilever
• Unrestricted cantilever testing will determine max
deformation limits of cantilevers and whether or not a
block is needed to restrict deformation.
• Cantilevers will be designed so that they bend freely
with only slight vibration.
• Test Plan
• Set up cantilever assembly on vibe table
• Measure deflection using high speed camera
49
PEA Subsystem continued
Cantilever Tests continued
Restricted Cantilever
• Restricted cantilever testing will ensure that designed
block will restrict deformation as needed such that PEA
won’t deform past piezo deformation limits.
• Block will be designed to restrict deformation in the +
and – axis.
• Test Plan
• Same as unrestricted tests except for use of block.
50
PEA Subsystem continued
Thermal and Adhesive Tests
• Thermal tests will be used to determine thermal
expansion of the piezos once adhered to the
cantilever. This will ensure that the piezos don’t
crack once adhered.
• Results will determine adhesive to be used.
• Test Plan
• Adhere piezo actuator to cantilever material
• Subject assembly to cyclic thermal environment
• Bake in oven, then put in freezer
51
EPS Subsystem and Software
Arduino Sampling Rates
• Tests will ensure Arduino board records at highest
sampling rate possible.
• Test will be completed after all subsequent
electronics are tested.
• Test Plan
• Connect all systems to Arduino board, click system
on with G-switch
• Set resolution
• Iteratively check data collection while increasing
sampling rates
52
EPS Subsystem and Software
Arduino Data Collection
• Tests will ensure Arduino board records data as
required.
• Test will be completed after all subsequent
electronics are tested.
• Test Plan
• Connect all systems to Arduino board, click system
on with g-switch.
• Check for data collection and storage.
• Modify software as needed.
53
EPS Subsystem and Software
G-switch Program Test
• Tests will ensure that G-switch activates system with
one click and does not deactivate the system on
subsequent clicks.
• Test Plan
• Program G-switch, connect to any system
• Will test with dummy system and with full EPS system
once other tests are complete
• Click system on, ensure function; click again, check
that system did not shut off
54
VVS Subsystem
Camera Activation
• Tests will ensure camera relays function properly.
• Power down requirement includes camera. Camera
will be relayed to g-switch to be activated upon
launch.
•
Test Plan
• Connect camera to G-switch, click system on and
check that camera turns on and records.
• Check that video saves at the end.
55
Full System Testing
Vibration Testing
• Tests will ensure system is structurally sound during
vibration.
• Test Plan
• Construct and connect full system
• Use vibe table to simulate Terrier-Orion flight vibration
conditions
• Monitor system connections and structural integrity
throughout test
• Check for data collection on Arduino board and
camera at end of tests
56
Full System Testing
Spin Testing
• Tests will ensure system is structurally sound during
spin.
• Test Plan
• Construct and connect full system
• Use spin table to simulate spin of Terrier-Orion rocket
• Monitor system connections and structural integrity
throughout test
• Check for data collection on Arduino board and
camera at end of tests
57
Kelly Collett
Prototype Risk Assessment
Subsystem
Risk/Concern
Action
STR
Concerns exist about
clearance and
component mounting
Prototype all interfaces
with STR to ensure
integrity
PEA
Bond between PE
actuators and aluminum
must not fail
Test various bonding
materials and application
methods
EPS
Functionality of
microcontroller must be
verified by CDR
Prototype controller on
bread board to verify
function
VVS
LED must light, camera
must not fail to record
actions of LED
Test LED with PEA to
verify power draw;
test camera to ensure
functionality
59
Risk Walk-Down risks at PDR
Consequence
EPS.RSK.2
EPS.RSK.1
•
STR.RSK.1 – Clearance and
component mounting
•
PEA.RSK.1 – Bonds between PE
actuators and cantilevers must
not fail
•
PEA.RSK.2 – PEA actuators
cannot fracture
•
EPS.RSK.1 – Functionality of
Microcontroller
•
EPS.RSK.2 – G-switch must not
shut off system
•
VVS. RSK.1 – LEDs must light
•
VVS.RSK.2 – Camera must
record LED light and cantilever
deflection
PEA.RSK.2
STR.RSK.1
PEA.RSK.1
VVS.RSK.1
VVS.RSK.2
Possibility
Risk Matrix at PDR
60
Risk Walk-Down top 3 risks at CDR
EPS.RSK.2
EPS.RSK.1
PEA.RSK.2
• Top 3 Risks
Consequence
• PEA.RSK.2
PEA fracture
• EPS.RSK.2
G-switch
• EPS.RSK.1
Microcontroller
• Will be walked
down with testing
Possibility
Top 3 Risks Remaining
61
Kelly Collett
User’s Guide Compliance
Magnitude of Mass
•
Approximately 2.091 lbf (without ballast)
CG
•
Lies within 1 in.3 volume at center
Power Requirements
•
•
Low voltage electrical components used
Batteries
•
4 x 1.5-V AA = 6 V
63
Kelly Collett
Organizational Chart
Danielle Jacobson
Christopher Elko
Electrical Systems Lead
Structural Lead
Machining
CAD Designer
Dr. Jin Kang
Faculty Advisor
Kelly Collett
Testing Lead
Drexel Space
Systems Lab
Primary POC
Project Support
65
Schedule December & January
Testing
Deliverables
12/1
Prelim. cantilever FEM
12/8
CDR Due
12/12-22
G-Switch programming
12/13
CDR Teleconference
Arduino software
programming
Temple CDR Teleconference
Destructive piezo testing
Cantilever tests
1/9-24
Thermal / Adhesive Tests
1/9
Flights Awarded
Software Iterations
1/30
Online Progress Report due
VVS Camera Tests
Preliminary EPS Integration
Redesigns, if necessary
66
Schedule February & March
Testing
February
VVS Testing
Re-test of any redesigns
Full system hook-up tests
Deliverables
February
2/6
Midterm Draft Report Due
2/1
3
Subsystem Test Reports
Due
2/2
7
Progress Presentation to
Faculty Advisor
March
3/1
2
Online Progress Report due
3/1
9
Project Progress Report
due
67
Schedule May
Testing
Subsystem and system testing,
troubleshooting, and
modifications as needed
Deliverables
5/7
Weekly Teleconference
5/14
Weekly Teleconference
Senior Design Project
Report Due
5/21
Weekly Teleconference
5/215/22
Final Senior Design
Presentations
5/28
LRR Presentation Due
5/29
LRR Teleconference
5/30
CoE Project Competition
68
Budget
Spending to date: $238.48
Estimated final total: $503.23
Budget: $1,000  Lookin’ Good!
Major Cost Contributors
Digital Camera: $140
Piezoelectric Components: $100
Major Time Contributors
Piezoelectric Components: 7-10 Days
Accelerometers: 7-10 Days RECEIVED!
69
Budget Ordered Parts ($238.48)
Item
Subsystem
Supplier
Cost/Set or Unit
Sets
Subtotal
Bridge Rectifier
EPS
DigiKey
$0.62
2
$1.24
Piezo Actuator
PEA
STEMInc.
$19.98
1
$19.98
Piezo Actuator
PEA
STEMInc.
$19.98
2
$39.96
Piezo Actuator
PEA
STEMInc.
$19.98
2
$39.96
STR
McMaster
$7.23
2
$14.46
EPS
Pololu
$14.95
2
$29.90
EPS
DigiKey
$4.39
2
$8.78
EPS
SparkFun
$58.95
1
$58.95
STR
McMaster
$1.05
5
$5.25
STR
McMaster
$20.00 allowance
N/A
$20.00
12” x 12” Acrylic
Sheet
3-Axis
Accelerometers
G-Switch
Arduino MEGA
Microprocessor
Aluminum
Standoffs
Miscellaneous
Fasteners
70
Budget To Be Ordered ($290)
•
Camera ($140)
•
Circuitry Components ($100)
• Parts for testing and installation
• We have some spare parts, so orders will be made
on an as-needed basis
•
Structural Materials ($50)
• We have some spare materials, so orders will
be made on an as-needed basis
71
Sharing Logistics
Temple 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
72
What’s Next?
Next Steps
•
•
•
3 days’ worth of sleep for each
member of the team
Prototype assembly
Testing testing testing!
74
Questions?