MEAM 610 BLIMPS Mohit Bhoite and Saurabh Palan

Introduction �Blimps �Anatomy �Design �Control �Sensing

Anatomy of a Blimp “A blimp, or non-rigid airship, is an airship without an internal supporting framework or keel. ” - wiki Stabilizers Envelop Motors Propellers Gondola

HELIUM - Calculating Lift �At standard temperature and pressure, mass density of �Air : ρair = 1. 293 kg/m 3 �Helium : ρHe = 0. 178 kg/m 3 �Neon: ρHe = 0. 9 kg/m 3 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 Lift Wload = [1. 1149 x volume – Wenv ] Kg Thumb rule : 1 m 3 of helium can lift 1. 1 kg of load

Latex Balloons vs. Rigid Envelops �Which 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 Designs �Off-the-shelf Options �Cost $25, 7 cu feet $12 $13, 5 cu feet $4, 3’ dia

Propulsion �DC Brushed motors + Propellers �Flapping wings/fins !

Propeller Placements

Controller Architecture Sensors Main Controller (u. P, u. C) Camera Wireless Link Motor Driver Motors, Servos

Sensors �Gyros �Acceleros �GPS �Digital Compass �Ultrasonic �Pressure sensor �IR �Vision

Digital Compass Specifications Voltage 5 v Current 20 m. A Typ. Resolution 0. 1 Degree Accuracy 3 -4 Degrees approx (after calibration) Output 1 Timing Pulse 1 m. S to 37 m. S in 0. 1 m. S increments Output 2 I 2 C Interface, 0 -255 and 0 -3599 SCL Speed up to 1 MHz Weight 0. 03 oz. Size 32 mm x 35 mm Devantech, acroname. com, $57

Digital Compass • I 2 C interface • 2. 7 to 5. 2 V supply range • 1 to 20 Hz selectable update rate • True drop-in solution • 0. 5 degree heading resolution • 1 degree repeatability • Supply current : 1 m. A @ 3 V Sparkfun. com, $60

Pressure Sensors �Barometric pressure sensing for altitude measurement �Can achieve resolution of about 10 cm at sea level �Pressure decreases at the rate of 100 millibars per 800 meters $55

Thank you!