BLIMPS
description
Transcript of BLIMPS
BLIMPSMohit Bhoite and Saurabh Palan
MEAM 610
IntroductionBlimps
AnatomyDesignControlSensing
Anatomy of a Blimp
Envelop
Gondola
Motors
Stabilizers
Propellers
“A blimp, or non-rigid airship, is an airship without an internal supporting framework or keel.” - wiki
HELIUM - Calculating LiftAt standard temperature and pressure, mass density of
Air : ρair = 1.293 kg/m3
Helium : ρHe = 0.178 kg/m3
Neon: ρHe = 0.9 kg/m3
Wload = [(ρair – ρHe) x volume – Wenv ] Kg
Grade A Helium gas = 99.995% He and 0.005% Ne
Wload = [(ρair - 0.99995ρHe - 0.00005ρNe) x volume – Wenv ] Kg
HELIUM - Calculating LiftWload = [1.1149 x volume – Wenv ] Kg
Thumb rule : 1m3 of helium can lift 1.1 kg of load
Latex Balloons vs. Rigid EnvelopsWhich one is better?
Balloons have internal pressure much higher than atmospheric => unnecessary helium mass => no extra lift
Rigid envelops will have pressure equivalent to atmospheric pressure => better efficiency
Envelop Designs
Envelop DesignsOff-the-shelf OptionsCost
$25, 7cu feet
$13, 5cu feet
$12
$4, 3’ dia
PropulsionDC Brushed motors + PropellersFlapping wings/fins !
Propeller Placements
Propeller Placements
Propeller Placements
Controller Architecture
Main Controller(uP, uC)
Wireless Link
Motor Driver
Motors, Servos
Sensors
Camera
SensorsGyrosAccelerosGPSDigital CompassUltrasonicPressure sensorIRVision
SensorsGyrosAccelerosGPSDigital CompassUltrasonicPressure sensorIRVision
Digital CompassSpecifications
Voltage 5v
Current 20mA Typ.
Resolution 0.1 Degree
Accuracy 3-4 Degrees approx (after calibration)
Output 1 Timing Pulse 1mS to
37mS in 0.1mS increments
Output 2 I2C Interface, 0-255 and 0-3599
SCL Speed up to 1MHz
Weight 0.03 oz.
Size 32mm x 35mm
Devantech, acroname.com, $57
Digital Compass
Sparkfun.com, $60
•I2C interface •2.7 to 5.2V supply range•1 to 20Hz selectable update rate•True drop-in solution•0.5 degree heading resolution•1 degree repeatability•Supply current : 1mA @ 3V
Pressure SensorsBarometric pressure
sensing for altitude measurement
Can achieve resolution of about 10cm at sea level
Pressure decreases at the rate of 100 millibars per 800 meters
$55
Thank you!