Hybrid Airship

This is a photo of the hybrid airship the Funky Shiitake Mushrooms finished building in spring of 2009. Our design was a two envelope hybrid airship equipped with a wireless camera, LiPo battery, three ESCs, a receiver and transmitter equipped with 2.4GHz technology, four motors and four propellers (two on the vertical axis, two on the horizontal axis):

The Project

It all started with Tech Challenge’s 2009 competition, Explore the Volcano: a local competition against high schools in the Bay Area. We decided to build a simple, inexpensive aircraft that was maneuverable, fast, and stable for the challenge. After looking at helicopters and fixed-wing aircraft, we decided that a more original design would better suit our needs: a hybrid airship combining vertical thrusters with helium envelopes.

Our basic design, as done on the computer (everything’s better in CAD).

Over the next few months, we designed and prototyped a tele-operated hybrid airship capable of lifting a few hundred grams. We have been delighted to find that it is nearly impossible to damage and safe to use indoors around people, which makes it a promising platform for aerial robotics. It can change direction quickly and turn in place, making a full 360-degree turn in a little over one second.

In April we entered this device in Tech Challenge 2009, winning a thousand dollars and a chance to meet Al Gore. In June of 2009, we entered the open category of Robogames, taking second place and in this August we entered the Digital Open, taking home a team laptop and a Grand Prize. Click on the menu on the left to see more about the competitions!

Future Plans

The success of our prototype has prompted us to add microcontrollers and develop our airship into an autonomous device. Yes, that’s right: we want our device to navigate, conduct surveillance, and interact with the environment on its own. Some of the uses that we have thought of for our airship include military reconnaissance, hostage negotiation, and inspection of hard-to-reach places; to those ends, we are planning to put together multiple configurations of our airship using cameras, intercoms, and servo manipulators for opening doors and lifting loads. In addition, another one of our goals is to create a better power system that would allow it to operate for days on end.

By the way, we have no relation whatsoever to these guys, hybrid airships from Lockheed Martin that are getting deployed in Afghanistan. In fact, we never heard of them until they appeared all over the Internet in September.

Although you have to admit, there is a certain family resemblance.

Software and Control

On the software side, our goal is to create a codebase to allow an airship of our design to maneuver without a human operator. To that end, we have started considering wireless microcontrollers that would allow us to make the airship semi-autonomous. We’re currently testing two microcontrollers (AVR RZRaven, TI MSP430) that cost about $50 each.

Our current plan is to integrate the two controllers into a system so that they are not only critical system redundant but also cooperative, using the following:

• AVR RZ Raven
• TI MSP430
• laptop PC
• joystick inputs
• GPS reciever
• accelerometer
• gyroscopes

AVR RZ Raven
The AVR RZ Raven is based off of the ATmega series of microcontrollers. The Raven is designed for prototyping wireless solutions and has built in ZigBee networking. It features 4 easily accessible GPIO pins and a relay driver circuit built it. It also has an integrated LCD panel and microphone and speakers.

TI MSP430
The TI MSP430 is a series of low-power microcontrollers. We are using TI’s wireless development boards – in particular, a ZigBee enabled wireless board that’s about one inch square. These have a total of 18 GPIO pins, as well as the usual serial bus and communication chips.

The intent of our system is to provide an extremely wide varied system of control. The AVR RZ Raven will direct critical flight systems, namely, the maneuverability controls and the failsafe emergency cutoff system. The TIMSP430 will control manipulator arms and sensor inputs, which can then be relayed to the control computer or passed to the AVR RZ Raven using ZigBee. GPS, accelerometers, and gyroscopes should give us navigational capabilities. With our newly upgraded systems, we hope to achieve basic aerobatics (aileron roll, barrel roll) and auto waypoint navigation.

Then, we’ll start working on a barebones version for all the starving hackers and photographers out there.

Materials

Using these microcontrollers, the total cost of an airship is about $350. That’s around the cost of an off-the-shelf model helicopter outfitted with camera, sensors, and gyroscopes, and compared to a helicopter, our device is much easier to pilot, has longer operating times, and has lower-cost consumables; as a result, we see our airship as a device with potential as a research project and as a platform for hobbyists.

No Materials section would be complete without a bill of materials, so here is ours:

FSM Hybrid Airship, Mark II

The FSM Hybrid Airship, lowest-cost version (preliminary)