full mission simulation and testing report: west virginia university
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Justin Yorick, Ben Province, Marc Gramlich , William Kryger , Alex Bouvy Advisor :Dimitris Vassiliadis. Full Mission SIMULATION AND Testing Report: WEST VIRGINIA UNIVERSITY. Mission Overview. - PowerPoint PPT PresentationTRANSCRIPT
FULL MISSION SIMULATION AND TESTING REPORT:
WEST VIRGINIA UNIVERSITY
Justin Yorick, Ben Province, Marc Gramlich, William Kryger, Alex Bouvy Advisor:Dimitris Vassiliadis
Mission Overview The purpose of the WVU payload is to
measure several physical parameters of the atmosphere as a function of altitude.
Experiments include:GHGE- Greenhouse Gas ExperimentRPE- Radio Plasma ExperimentCRE- Cosmic Ray ExperimentCLE- Capillary Liquid ExperimentFD- Flight Dynamics
3
WVU Payload 2012: Concept of Operations
h=75 km (T=01:18) RPE Tx ON
h=75 km (T=04:27)RPE Tx OFF
h=117 km (T=02:53)Apogee
h=0 km (T=13:00)Splashdown
h=10.5 km (T=05:30)Chute deploys
h=52 km (T=00:36)End of Orion burn
H=1.52 km t=004.x s Wallops Valves Open
H=1.52 km t=771 s Wallops Valves CloseSolenoid Valves Close
h=0 km (T=00:00)Pre-Launch activation signal
GHGE processor and sensors power up
WVU Payload The updated payload is shown here:
GHGE
CRE
FD
RPE
Not shown: CLE
Subsystem Overviews
Subsystem Overview Greenhouse Gas Experiment(GHGE): The
GHGE is designed to measure the concentration of Carbon Dioxide, water vapor and ozone gas concentrations as function of altitude in the atmosphere. The system uses a dynamic port for air input and a static port for exhaust.Currently the mechanical components of the
GHGE are assembled and operational with temporary “patch brackets” and an interim control volume highlighted on the next slide.
Greenhouse Gas Experiment “Patch
Brackets”
Interim CV
Original Brackets
Plumbing and Solenoid Valves
Subsystem Overview Flight Dynamics (FD):The FD
subsystem is responsible for measuring the kinematics of the payload in flight. From this information, the data from all other subsystems can be correlated to altitude of the payload.
Flight Dynamics
Revised FD Circuit Board (3D Rendering)
Revised FD Circuit Board(Trace Schematic)
Subsystem Overview Radio Plasma Experiment (RPE): The
RPE will measure the density of ambient plasma in the ionosphere. A ferrite rod will act as a transmitting and
receiving antenna for the 1.3-6.3 MHz signalsA patch antenna at a special port of the rocket
will be used to transmit the 5.826 GHz signal A Langmuir probe will be used as a
secondary sensor.
Subsystem Overview Cosmic Ray Experiment (CRE): The
CRE will use an array of Geiger tubes to record the flux of high energy particles.
These tubes have varying thickness of shielding to identify various energies of particles based on penetrating power.
Subsystem Overview Capillary Liquid Experiment (CLE):
The CLE records the dynamic capillary actions of a liquid in the microgravity conditions experienced in portions of the flight. This behavior will be monitored by recording the position of the fluid against a gridded background. Parts for this experiment are ready to fly from last year.
Full Scale Testing The full scale testing is initiated by using
the activation signal. With this activation, the entire payload
control scheme begins operation. The remainder of the report details the
testing sequences performed on each subsystem.
Testing Protocols
GHGE Testing Protocols Flow Test Simulation of flow in manifold structure has
proven difficult and inconclusive. Flow rates under different solenoid
configurations is a requirement for effective GHGE control scheme.
Using a flowmeter, the GHGE manifold flow rates will be measured after exposing the dynamic input to pressurized air, and the static exhaust to atmosphere.
GHGE Testing Protocols Internal Volume Test To optimize the control scheme
parameters, a precise internal volume of the manifolds and testing volume must be known.
Using the system temperature and pressure sensors, the internal volume will be calculated by inducing a known change in volume via the piston and observing the pressure change.
GHGE Testing Protocols Gas Concentration Tests By using concentrated carbon dioxide
gas and water vapor, the team can test the steady state and transient responses of the gas concentration sensor.
These gases are added to the flow at the dynamic input port.
GHGE Testing Protocols Linear Actuator Transient Response The linear actuator is used to compress air
under different dynamic conditions. It is of interest to know how long the
actuator takes to achieve full piston compression under different pressure loads.
The power required to compress the gas will be recorded and used to update the power budget.
RPE Testing Protocols Waveform Generation Test The RPE relies on the generation of a
variable frequency pulse sweep. To ensure the proper waveforms are
produced, the output signal will be measured by an oscilloscope.
The oscilloscope used in the lab is capable of displaying and capturing waveforms as well as performing frequency analysis.
RPE Testing Protocols Patch Antenna The patch antenna will be tuned and
impedance matched to the 5.826 GHz transmitter using a network analyzer
RPE Testing Protocols Data Writing Test The RPE writes data in ASCII format to a flash
memory SD card. This data is imported into Matlab and the data packets are converted to useable measurements.
Matlab informs the user of corrupted data packages in this process.
Such analysis allows the team to verify the data writing process is working properly.
This data writing process is the same for the remaining subsystems as well.
FD Testing Protocols Kinematic Perturbation Test One of the main goals of the FD
subsystem is to measure kinematic variables in the rocket flight.
By activating this subsystem and exposing it to small fast controlled perturbations by hand, the sensor response can be recorded and tested for proper response.
FD Testing Protocols Magnetometer Test By exposing the magnetometer to a
magnetic field generated by a local permanent magnet, the sensor response can be calibrated.
CRE Testing Protocols Geiger Rate Count Test The Geiger arrays are used to measure
pulse activation caused by particle collisions within a time interval.
Using a known radioactive source the count rates of the CRE can be measured.
This test also inherently tests the data recording and software formatting for the CRE.
Testing Results
GHGE: Subsystem Assembly and Testing (top view)
GHGE: Subsystem Assembly and Testing (side views)
GHGE: Control Volume Testing
GHGE: Flow Test This test is not yet complete. We have
secured a compressor, vacuum pump, regulators, and a flowmeter, but require additional fittings to connect the components.
The flow test for the GHGE with the interim control volume is expected to be completed the week of April 23rd.
GHGE: Internal Volume Test This test is not yet complete. The
Internal Volume Test requires pressure sensors to be present in the control volume as well as the high-pressure manifold.
This test is expected to be completed the week of May 7th.
GHGE: Sensor Control and Data Acquisition Test
GHGE: Gas Concentration
GHGE: Gas Concentration
GHGE: Modeled Time Constants (rise) CO2 Tank Manifold Pressure (psi)
Test Type (cold/hot) Time Constant
38 Cold 7.80
50 Cold 13.25
60 Cold 21.60
40 Hot 3.7
• At this point, more testing is needed for the hot test configuration.• CO2 pressures need to be related to expected flow regimes in
payload flight.
GHGE: Linear Actuator ResponsePressure
DifferenceFull-Stroke
Actuation Time Voltage Current Power Energy (approx)
PSIG s v A W mW-hr
0 1.31 12 0.4 4.8 1.7
5 1.35 12 0.7 8.4 3.2
10 1.44 12 1.0 12.0 4.8
15 1.56 12 1.3 15.6 6.8
20 1.71 12 1.5 18.0 8.6
25 1.82 12 1.6 19.2 9.7
30 1.90 12 2.1 25.2 13.3
35 1.97 12 2.6 31.2 17.1
GHGE: Linear Actuator Response
0 5 10 15 20 25 30 35 400.00
0.50
1.00
1.50
2.00
2.50
f(x) = 0.0206190476190476 x + 1.27166666666667R² = 0.985979858536457
Actuation Time
Actuation Time
Linear (Actuation Time)
Pressure Difference (PSI)
Actu
atio
n Ti
me
(s)
Actuation time for each pressure difference was measured with a stopwatch
GHGE: Linear Actuator Response
0 10 20 30 400.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
f(x) = 0.697142857142857 x + 4.6R² = 0.973574045002616
Power
Power
Linear (Power)
Pressure Difference (PSI)
Pow
er (W
)
Motor power consumption calculated as the product of steady-state current and potential.
GHGE: Linear Actuator Response
0 5 10 15 20 25 30 35 400.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0
18.0
f(x) = 0.00669523809523803 x² + 0.18125396825397 x + 2.03472222222221R² = 0.990249135483274
Energy (approximate)
Energy (approx)
Polynomial (Energy (approx))
Pressure Difference (PSI)
Ener
gy (m
W-h
r)
Approximate energy was calculated by multiplying power by time.
This does not include energy estimation does not include losses encountered in the mechanical components.
GHGE: Linear Actuator Response Test Setup
Current Potential
Compressed air at dynamic port
Static port exhausted to atmosphere
GHGE: Linear Actuator Response Other Useful information:
The drivetrain will self-start when the motor is unpowered if the pressure difference in the piston-cylinder is greater than 12 PSI.
The solenoid valves require at least 10v to open, but will remain in the open position when voltage is stepped down to 3v. Due to their fixed resistance and Ohm’s law, current draw is also significantly reduced by lowering the voltage.
GHGE: Linear Actuator Response While under pressure, the piston tends to turn in
the cylinder. This will cause problems with the rotary optical
encoder based position sensing strategy. We are currently exploring options including:
Replacing the rotary optical encoder with a linear potentiometer
De-emphasizing the encoder data in the control scheme by allowing the piston to hit end-stops and making decisions based on pressure instead of position.
Adding a keyway to the ballscrew.
RPE: Waveform Test The following figures show sample
waveforms obtained from the RPE waveform generator.
RPE: Wave Output
RPE: Antenna Testing The antenna has been tested for
frequency response. Due to nature of testing apparatus, a graphic of these responses is not available at this time. It has been found that the antenna has a loss of 21dB at 5.826GHz.
FD: Sensor Tests
IMU sensor
Gyro
NetBurnersocket
FD: Gyro Test
Z-Axis Gyro Test
FD: Magnetometer Test
FD: Magnetometer Test (cont.)
FD:IMU Testing
FD: IMU Testing (cont.)
CRE: Geiger Counter Assembly
CRE: Geiger Rate Test The following graphs summarize the results of the Geiger
test for a single tube. It can clearly be seen that the CRE electronics are
operational.
Work Breakdown Schedule
Conclusions From This Test Stage The FD, CRE, and CLE subsystems are
nearing completion The RPE subsystem has all components
built and ready to be integrated. The system is currently in the tuning and optimization stage.
The GHGE subsystem sensor components and actuators have been tested. Full integration of the system is underway.