TEAM TESLA Anthony Thompson Philip de la Vergne Aaron Wascom Brandon Sciortino 1.
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Transcript of TEAM TESLA Anthony Thompson Philip de la Vergne Aaron Wascom Brandon Sciortino 1.
2
Overview
• Address concerns from previous PDR presentation• Polarity• Humidity• Temperature• Linear Actuator• Breakdown Voltage at Sea Level• Data Accuracy• Data Frequency• Requirements• System Design• Traceability• Software• Principal of Operation• Payload Development• WBS
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Humidity
Effect of absolute humidity on the breakdown voltage of a 30cm point-to-plane spark gap
Parameter: VoltagePositive D.C Voltage
A.C. Voltage
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Temperature
Lower temperatures mean slower molecules, which means that the particles in the air collide with less kinetic energy.
This drop in energy apprehends the production of ions and free electrons, which decrease the current created through the corona breakdown mechanism
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Data• If the payload passes through a cloud the humidity will
change rapidly making Its effect on the breakdown voltage more evident.
The Smallest cloud () is about 1000 ft. tall so it insure we get a measurement inside the cloud we will measure no less than every 500 feet
We ascend 1000 ft. per min and want to sample every 500 ft. so we will measure every 30 second's .
• How accurate to our results need to be?• Temperature, Pressure, Humidity, Current, Voltage
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Linear Actuator
• Data must be taken every 500 feet.• A actuator will increase the distance across the spark gap
to prevent a breakdown and the distance at that instant will be recorded.
• An analysis of the expected results of this method reveals that it is not plausible.
• The linear actuator would have to change the spark gap 19 mm every 500 ft.
• Assuming a constant voltage of 3000 V, the sea level pressure distance product on the x-axis of Paschen’s curve is 3 Torr-in. This requires a gap distance of 1.002 mm the gap distance would have to change by 19 micrometers every
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Technical Requirements
• The payload shall have a temperature sensor that can measure from 40 °C to -70° C and operate throughout the flight.
• The payload shall measure Temperature to an accuracy of 1 degree Celsius
• The payload shall measure Pressure to an accuracy of 1 Pa• The payload shall have a humidity sensor that can measure 0 to
100% relative humidity and operate throughout the flight.• The payload shall measure relative humidity to an accuracy of 1%• The payload shall have a pressure sensor that can measure 101.3
kPa to 1 kPa and operate throughout the flight.
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Technical Requirements• The payload shall provide up to 4.5 kV in order to create a corona
discharge at ground level• The electrodes shall have a point to plane configuration• The payload shall have a 1 mm spark gap• The electrodes shall be properly conditioned to provide a smooth
finish• The anode shall be composed of a gold-plated copper point and
the cathode shall be composed of copper• The payload shall weigh less than 500 grams.• The payload shall have two holes 17 cm apart for interfacing with
the LaACES balloon.• Record and store data from flight so that it can be retrieved after
flight for analysis• The payload will have enough power to operate throughout entire
flight.
10 Science Requirements
• The electrodes shall be exposed to external temperature and humidity conditions
• This payload shall consider a corona discharge of 10-5 Amps to be a breakdown
• The payload shall increase the voltage with an accuracy of
• The electrode configuration shall create a positive corona discharge
• The onboard electronics shall be protected by a Faraday Cage around the spark gap
• The payload shall record data every 500 feet to observe any clouds in the flight profile
• The payload shall record temperature, pressure, humidity, and breakdown voltage from 0 to 100,000 feet
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Principle of Operation
• Measure pressure, temperature, humidity, breakdown voltage, and current across the spark gap
• Sensors: Piezoelectric, thermistor, relative humidity• Exposed to environmental conditions• Voltage across spark gap increased until 10 microamps
are measured• Voltage comparator observes corona discharge• Switch opened, data recorded, voltage set to zero
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Electrical Development
• Temperature Sensor• Select sensor that operates within requirements
• Measure from -70 to 40 degrees Celsius• Operates within 40 degrees Celsius• Accurate to +/- 1 degree Celsius
• Order Sensor• Draw preliminary schematic• Measure accuracy and compare to data sheet accuracy• Calibrate sensor according to difference between data sheet and
observed accuracy• Determine necessary gain for op-amp conditioning circuit• Select resistors for op-amp circuit• Test to operate under 100% relative humidity• Test performance in thermal/pressure environments
14 Electrical Development
• Pressure sensor • Select sensor that operates within requirements• Measure from -70 to 40 degrees Celsius• Operates within 40 degrees Celsius• Accurate to +/- 133 Pa• Order Sensor
• Draw preliminary schematic• Measure accuracy and compare to data sheet accuracy• Calibrate sensor according to difference between data sheet
and observed accuracy• Determine necessary gain for op-amp conditioning circuit• Select resistors for op-amp circuit• Test to operate under 100% relative humidity• Test performance in thermal/pressure environments
15 Electrical Development
• Humidity sensor• Select sensor that operates within requirements
• Measure from -70 to 40 degrees Celsius• Operates within 40 degrees Celsius• Accurate to +/- 1%
• Order Sensor• Draw preliminary schematic• Measure accuracy and compare to data sheet accuracy• Calibrate sensor according to difference between data sheet and
observed accuracy• Determine necessary gain for op-amp conditioning circuit• Select resistors for op-amp circuit• Test to operate under 100% relative humidity• Test performance in thermal/pressure environments
16 Current Detection
• Flight simulation• Compare to expected results to confirm system design
• Draw Preliminary Schematic• Select resistor for voltage comparator circuit
• Must allow for 10 microamps created at lowest voltage created• Select threshold voltage across resistor for voltage comparator• Select voltage comparator from threshold voltage, environmental
requirements and 2ms response time• Operate from 40 to -70 degrees Celsius
• Select JK Flipflop• Operate from -70 to 40 degrees C• 2ms response time
• Determine high voltage at JK Flipflop for high at BASIC Stamp• Select transistor
• Response time less than 2ms• Test transistor to confirm response time• Purchase materials for electrode configuration
• Test to determine breakdown voltage at sea level• Finalize circuit schematics• Flight simulation
• To confirm system design
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Mechanical Development• Determine required volume to contain components• Determine method of component attachment to payload• Determine required dimensions for interfacing and components• Thermal test to determine required thickness• Shock test• Add to weight budget
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Software Development• Read/Write to EEPROM
• Determine syntax needed to input and output data to EEPROM
• Develop subroutine to write data to EEPROM• Develop subroutine to prevent overwriting• Test to confirm coding
• Reading sensors• Develop subroutines to
• Record data from ADC• Read data from EEPROM• Timestamp data
• Control Voltage• Develop subroutine to increase voltage• Test output voltage sent to DAC from BASIC Stamp• Ensure HVDC output voltage is the same value indicated by
BASIC Stamp• Develop subroutine to record breakdown voltage• Develop subroutine to remove voltage across spark gap
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Mission Development
• Full flight simulation prior to trip• Bring extra batteries, sensors, voltage comparator, JK flipflop,
resistors, and HVDC• Assemble payload 24 hours prior to launch
• Test operation off all components prior to launch• Launch
• Run Pre-flight software that leads into operations software
20 HVDC Development
• Select and order HVDC based on electrode testing• Required breakdown voltage from materials testing
• Draw Preliminary Schematic• Test and compare measured accuracy to data sheet• Calibrate HVDC according to difference between data sheet and tests• Determine required input voltages to create desired output voltages• Test performance in thermal/pressure environment• Draw finalized schematics• Flight simulation
• Compare to expected results to confirm system design
• Add all sensors to weight and power budget
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Overview
• Mission Goal• Science Objectives• Technical Objectives• Science Background• Science Requirements• Technical Requirements• System Design• Power Budget• Software Design• Structural Design• Management
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Mission Goal
• To study the effects of humidity and temperature on the corona breakdown of the atmosphere in an effort to prevent sparking and ensure safety on future payloads.
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Science Objectives
• Observe the effect of temperature on corona breakdown voltage of the atmosphere
• Observe the effect of humidity on corona breakdown voltage of the atmosphere
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Technical Objectives
• Measure temperature of the atmosphere • Measure pressure of the atmosphere • Measure humidity of the atmosphere • Measure the corona breakdown voltage as a function of
pressure and gap distance• Measure the current across the gap• Meet all payload standards set by LaACES
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Electrode Geometry & Polarity
http://etd.auburn.edu/etd/bitstream/handle/10415/2044/Lipham_Mark_Thesis.pdf?sequence=1
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Effects of Humidity
• Humidity has an effect on the corona breakdown voltage by rearranging the polar water molecules entering the electric field.
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Effects of Temperature
• Temperature has an effect on the corona breakdown voltage through increasing the kinetic energy of the molecules within the spark gap.
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Science Requirements
• The electrodes shall be exposed to external temperature and humidity conditions.
• This payload shall successfully create a corona discharge.• The electrode configuration shall create a positive corona
discharge. • The payload’s onboard electrons shall be protected with a
Faraday cage.
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Technical Requirements
• The payload shall have a temperature, pressure, and humidity sensor that can measure and operate throughout the flight.
• The payload shall detect a corona discharge by intercepting a radio interference and detecting a current spike.
• The payload shall have an HVDC Converter.• The electrodes shall have a point-to-plane configuration.• The electrodes shall be properly conditioned.• The anode shall be composed of a gold-plated copper
point and the cathode shall be composed of copper.
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HVDC Converter
SMHV Series sub-miniature regulated HV DC • 0.434 cubic inch converter • 0 to 10kV at 1 W of power• 5VDC input• On/Off Pin• Voltage and Current monitor outputs • Current Limiting Control inputs
• SHORT LEAD TIME
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Current & Radio Wave Sensor Interface
Resistor
Conditioning ADCV out
CurrentMonitor
PinConditioning ADCV out
RWSensor
Conditioning ADCV out PeakDetector
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Power BudgetComponent Current Voltage Power Flight Time Capacity
HVDC ConverterSMHV SeriesEMCO
Full Load – 300 mA 5 V 1500 mW 4 minutes 20 mA-hours
Stand by – 20 mA 5 V 100 mW 3 hours 56 minutes
79 mA-hours
Humidity SensorHIH-5030 Series
200 μA 2.7 V 2.5 mW 4 hours 2 mA-hours
BalloonSat 52 mA 12 V 1790 mW 4 hours 208 mA-hours
Pressure Sensor1230 Series Measurement Spec
2 mA 12 V 24 mW 4 hours 8 mA-hours
Temperature Sensor44000 seriesOMEGA
1 mA 12 V 12 mW 4 hours 4 mA-hours
DAC 160 μA 5V .8 mW 4 hours .64mA-hours
Totals:
Full Load – 355.2 mAStand by – 75.2 mA
12 V Stand by – 1930 mWFull Load – 3330 mW
4 hours 322 mA-hours
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Flight Software Flowchart
Temperature: 1 byteHumidity : 1 bytePressure : 1 byteTime : 3 bytesVoltage : 2 byte Voltage Redundancy: 2 byteCurrent : 1 byte Current Redundancy :1 byteRadio : 1 bit
Total : 97 bits
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Thermal Design
Device Upper Temp (°C) Lower Temp (°C)
ADC, RTC, BASIC Stamp, EEPROM, DAC
80 -40
Pressure Sensor125 -40
Humidity Sensor125 -50
Temperature Sensor120 -80
HVDC85 -55
Current Sensor85 -40
Energizer Lithium Batteries
60 -40
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Weight Budget
Item Mass Uncertainty Measured or Estimated
BalloonSat67.6 g ± 5g Measured
Signal Conditioning 70 g ±5 Estimated
and Sensors
Packaging100 g ± 10g Estimated
Wiring15g ±5g Estimated
Power Supply150g ±10g Estimated
Totals:402.6g ±35g
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Group Structure
Functional Group Team Member
Project Management Anthony Thompson
Science Requirements Chris Rowan
Electronics Aaron Wascom
Flight Software Aaron Wascom
Mechanical Integration Philip de la Vergne
System Testing Brandon Sciortino
Data Processing and Analysis Anthony Thompson
Documentation Chris Rowan
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Risk ManagementRisk Event Likelihood Impact Detection Difficulty When
Faulty Power Supply 4 5 2 Flight
Faulty Preflight Procedure
2 4 4 Pre-Flight
Incorrect Coding 3 5 1 Calibration
Sparking 3 3 2 Flight
Losing a Team Member
2 3 1 Pre-Flight
Faulty Parachute 1 3 1 Flight
Component Failure 4 4 2 During Flight/ Testing
Impurities on Electrode Surface
3 4 2 Pre-Flight/During Flight
Loss of Payload 3 5 5 Post-Flight
External Deadlines not Met
2 5 3 Pre-Flight
Over Budget 3 4 2 Pre-Flight
Memory Deficiency 4 4 3 Flight
Unexpected Environmental Conditions
2 3 1 Flight
Part Unavailability 3 3 2 Pre-Flight
Change in Electrode Distance
2 5 5 Flight
Bad Connection During Fabrication
2 4 4 Fabrication
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Risk Event Response Contingency Plan Trigger Responsibility
Faulty Power Supply Reduce Switch out with new Batteries
Sensors Malfunction or Break
Philip de la Vergne
Faulty Preflight Procedure
Reduce Pre-Flight To-Do list Pre-Flight Set up Anthony Thompson
Incorrect Coding Reduce Recode Will not load to BASIC Stamp
Aaron Wascom
Sparking Reduce Electrode geometry, sparking type, and Faraday cage
Faulty Programming Aaron Wascom
Losing a Team Member
Reduce Work is shared among remaining members
Sudden Workload Increase
All Members
Faulty Parachute Transfer Build payload to protect data storage
Parachute failure Dr. Guzik
Component Failure Transfer Order another from a different company or have a spare
Device does not operate properly
Aaron Wascom
Impurities on Electrode Surface
Reduce Check surfaces prior to launch
Condensation or dust Brandon Sciortino
Loss of Payload Share Prepare Failure Report Lack of Payload All Members
External Deadlines not Met
Transfer Pray we don’t get fired Lack of Project Management
All Members
Over Budget Transfer Find cheaper Component or Apply for More Funds
Cost Analysis All Members
Memory Deficiency Retain Obtain more memory Loss of Data Points Anthony Thompson
Unexpected Environmental Conditions
Reduce Increase Sensor Ranges Sensor Failure and Data Spikes
All Members
Part Unavailability Reduce Different Supplier Research Supplier
Change in Electrode Distance
Reduce Strengthen stability of electrodes
Carelessness during Fabrication
Chris Rowan
Bad Connection During Fabrication
Transfer Double and triple check all solder joints
Faulty circuit Chris Rowan