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!