Download Force Resisting Canard Deployment

AMCOM MK66 guidance
system
11-18-2004
System interface specifications
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Rocket management system
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(Target acquisition system on helicopter)
IMU
GPS
Actuator system control
Controller I/O bus
Rocket management system
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Current system uses analog line for purposes of
charging a timing capacitor
Proposed implementation of an RS-232 digital
serial interface
RS-232 allows for target data transfer at
comfortable data rates, from 300bps to
115200bps.
Standard 9600bps baud rate will more than
likely suffice
Rocket management system
(cont’d)
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RS-232 implementation at 12V active-low
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Allows for debugging based on a PC serial port using
12V active-low
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PC may be used in conjunction with Matlab, C or other to
simulate rocket management system outputs
Data format based on target data:
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Allows for extended serial cable lengths
Current position and elevation
Target position and elevation
Current speed
Guidance module returns “target acquired” signal
IMU
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IMUs may provide analog or digital outputs; IMUs that
we have researched mostly output serial digital signals
2-wire serial outputs, 5V TTL to Altera serial I/O line
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I/O types:
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Standard to be defined
Δv, Δθ
9600bps transmission rate allows more than 8 times the
necessary data rate for 16 corrections/second
GPS
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Digital serial I/O lines
Provides P(x, y, z), ΔP(x, y, z)
5VDC (TTL-level power), no voltage
division required
Data transmission rate at 9600bps will
allow for more than 8 times the necessary
data rate for 16 corrections/sec
Altera Cyclone system buses
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Memory R/W/ADDR bus, 16MB system memory
(SDRAM), interface specifications allow for SDRAM
SDRAM in PC100 specification, managed by onboard
memory controller
Local serial, parallel buses
Actuator control:
 Via parallel ports, can be used in conjunction with
LM741/MIL741 and transistor drivers coupled to
relays to trigger actuator assemblies
 ADC ICs provide actuator position feedback, 8-bit
parallel port solution for feedback to FPGA controller
System clock rates allow for 50MHz modulation (more
than enough)
ser.
RMS
GPS
3
3
RS232
Actuator Control
4 ADC
Cyclone
3
IMU
Feedback
n
8 par.
ser.
SDRAM
PC100
Additional FPGA considerations
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Nios devel. kit has two serial ports; three are
required for this application:
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The RMS and IMU or GPS ports may be shared and
appropriately multiplexed
Actuators:
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8-bit parallel port can be set to drive actuator driver
circuit.
8-bit parallel ports (4) will be used for feedback
purposes from each servo with ΔV coming from an
ADC
Force Resisting Canard
Deployment
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Force acting on the canard due to
acceleration of 80g’s is 42.7N (10
lb) acting on the centroid.
(assuming canard dimensions in
diagram)
This relates to a torque of 2.7225
Nm
To open the canards with a force
applied 1 in from the pivot point, a
force of 106.75N (24lb) is needed
This force is possibly to large to
produce within the design
limitations (space and weight)
Optional Canard Deployments
1. Suicide
2. Different Shapes
NACA Airfoil
• 4 digit airfoil
•Example: 2412
•Max chamber 0.02c
•Camber max location 0.4c
•Max thickness 0.12c
Simulation: Upcoming Goals
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Researching and understanding DATCOM
Locating Aerospace Block Set and
learning the software
Analyzing various fin geometries
Creating new deployment mechanisms