05.07.09

Code under MIT

Posted in Software at 3:29 pm by Joël

The past few months we’ve been using Assembla to manage our code. Assembla provides easy to use SVN, Trac and wiki capabilities for free to Open Source projects. Since we strongly believe in Open Science we’ve decided to share our code under the famous MIT license.

Before you check out our code remember that we’re undergrad students with little to no experience with software development out of our classes. We’ll be gradually improving and expanding our code with the knowledge we’re acquiring.

Compiling and running the Java for the client side should be no problem with Java 1.6. The C/C++ code should be able to compile under linux with gcc. To cross-compile for the Verdex Pro (Open Embedded) you need to install the Open Embedded toolchain.

So go ahead and get the source!
http://svn2.assembla.com/svn/zeppy

04.17.09

Sort of completed

Posted in Hardware, General, Software at 3:03 pm by Joël

Wednesday was judgment day for the people at the Hanze University as that day signaled the ending of their 8 week project. Both Electrical Engineering and Mechanical Engineering worked hard to complete a working Zeppy before the 13:00 deadline. And succeeded, Zeppy flied beautifully!

There are some parts that still need a finishing touch, like the printed circuit board(PCB) and helium balloon. But for the demo we replaced the PCB with a experiment board (breadboard) which we were able to lift with a slightly over-sized balloon. Below are some pictures of this historical day!

See the Zeppy Set on Flickr for more pictures!

In other news our, slightly outdated, article for the Dutch magazine for Artificial Intellgence (de Connectie) got published! Head over to their site to see how you can get a copy!

Also we’ve made great progress on the client-side. We’re now able to remote control Zeppy with a Joystick and have made a GUI to read and set the status of Zeppy. Below is a screenshot of this system we call Uplink!

04.07.09

Nearing Completion

Posted in Hardware, General, Software at 7:35 pm by Joël

Our cooperation with the Hanze University is coming to an end. We expect to integrate the fruits of 9 weeks of hard labour into a great product by the end of next week. It has been an awesome experience and I hope that the students from the Hanze University can only agree. Out of nothing there will be a robotic zeppelin, which was not an easy task. Finding the right material for the helium envelope proved to be extremely hard and even after acquiring the desired material, coated mylar, working with it was also problematic. The imagination of the engeneering students was taxed with finding a suitable way of sealing the mylar envelope. Quite a few unorthodox methods of sealing have been explored and, ultimately, rejected. At the moment they are trying a combination of a special mylar glue and aluminium tape, which seems to be working. As for the gondola part the finalized blueprints are being sent to a 3D printer which was made available to us.

On the electrical engineering side of the story we were faced with the failure of our Gumstix module. This was a setback which was quickly overcome by buying a new Gumstix and Robostix. However easy this simple switching trick might seem it pulled some nasty tricks on us. There is no documentation on both components, not organized anyway. So for the electrical engineers this meant browsing the internet for hours to get the system back to its original state. Not an easy task when taking into account that the platform had switched from Buildroot to Open Embedded rendering most our i2c modules useless. The lack of i2c modules seemed to be easily fixed by compiling them from the available repositories, which were unavailable. We were able to get the system running again, however, and the AVR(a type of integrated circuit) software almost immediately worked its magic. The AVR will communicate to a custom Printed Circuit Board(PCB) which will provide access to the sensors and actuators. It’s a strange thing realizing that you’re communicating through a Bluetooth connection to a computer chip, talking to another computer chip which is making motors run. At a distance!

While the students at the Hanze University were developing the hardware, we focused on creating good software for developing the robots’ behavior. On the client-side we now have a functional graphical user interface, written in Java, which is able to sent and receive UDP(User Datagram Protocol) messages to and from Zeppy. On Zeppys’ side we are now able to receive these messages and parse them appropriately into C++ objects. It now only seems to be a matter of tying the generated C++ objects to the i2c-layer and we have a remote controlled blimp again! We’ve also started working on a simulation environment which will be able to simulate Zeppy’s behavior on a basic level and replay Zeppy’s logfiles so we can analyze them.

When Zeppy is completed the fun for us will really begin. We’re considering multiple techniques for autonomous behavior ranging from simple reactive control (like Braitenberg vehicles) to complex Simultaneous Localization and Mapping(SLAM) systems integrated in a hybrid control architecture. Keeping the zeppelin stable in an ever changing environment will also provide the necessary challenges and we are eager to try various control systems like PID-control or recurrent neural networks.

Of course we will flood this blog with pictures and video’s when we are able to show the brand new Zeppy but for now we have some fun videos and pictures!

Prototype Envelope

Prototype Envelope

Testing variable motor speeds using Pulse Width Modulation(PWM)