My virtual playground. Meer info


After a weekend (or two) of hard work, I’m proud to announce a new website: gluonpilot.com. It contains a wiki and a forum.
The account you create on the forum is also valid on the wiki (ask wiki rights if you haven’t got them automatically :-) ).

From now on, all my UAV-related posts will be on this site.
Also, I invite every one of you to enter the discussion or ask any questions you might have on the forum. Don’t be shy! Let’s build a community!

23 November 2009, 21:55 | Link | Comments [1]


A new child is born!

From now on, the hardware module will be known as GluonPilot.
A project has been created on google code. Until now, the first release only contains libraries and examples. I’m in the progress of re-writing portions of the current autopilot firmware to make sure it’s more modular, more easy to understand… so basically just better!

A forum will should be up and running shortly. If you’d have any ideas/remarks: please let me know!

8 November 2009, 18:07 | Link | Comments [3]

New hardware!

After a long struggle (which isn’t over yet), my new hardware finally arrived:

Designed to be as small and lightweight as possible: the weight is 8.6grams with a size of 46×59mm. The cool thing is that the profile of this board is only 6mm thick. This makes it also perfect for small UAV’s.

This high-precision yaw rate gyro makes this board a nice candidate for your next quadrocopter as well :-)

Its features are an extention of my previous versions:

  • 6DOF IMU (3 gyros and 3 accelerometers)
  • 16-bit pressure sensor for height
  • can control 6 servo
  • RC-transmitter input through PPM or PWM (4 channels)
  • a push button
  • 2 LEDs
  • 4MB flash for datalogging and configuration
  • 256kB flash for code
  • works with EB-85 GPS and other (4-pin) GPS modules
  • connects to your PC using the standard FTDI USB data cable
  • SPI, I2C, UART headers available for communication with other devices

And last but not least: the software

  • Easy to use libraries for all hardware
  • 11 simple demo applications for every hardware component
  • a simple autopilot
  • a more complex autopilot using FreeRTOS (work in progress)
  • all code nicely documented

However, still a lot of work has to be done. Attitude estimation needs to be improved, and a nice configuration tool would rock! It would be great if some people would show interest to join me in this effort!

Interested in joining or just in the board? Contact me

20 September 2009, 16:30 | Link | Comments [3]

Real-time OS

I wanted to send commands to my UAV during flight. Implementing this on my ground station was not hard at all. Doing the same on my autopilot software turned out not as easy: parsing (and validating data that could be gibberish) data coming from the serial interface could potentially disturb the strict timing needed for my kalman filtering. That strict timing also prevented my from doing some other telemetry and dataprocessing stuff.

It was time to port my code to a real-time operating system. Also a good excuse to start playing with it :-)
I’m not familiar with a lot of those “free” RTOS’s on the net, so I picked up the most common one: FreeRTOS

I had read the documentation a few times before, but never got to the coding part. It turned out pretty easy! Thanks to the modular approach i used in the autopilot software, porting it to FreeRTOS was finished in about an afternoon!
Now I can add various new functionalities without worrying how to fit it in the current code.

Another advantage is “Run time statistics”. Before I thought I used about 40% of the CPU, but it turns out that I’m only using 6% of it:

TickTask	267             <1%                                                                                                                                                                                      
IDLE    	49058           94%                                                                                                                                                                                      
5DofTask	2098            4%                                                                                                                                                                                       
ControlTask	481             <1%                                                                                                                                                                                      
GpsTask 	16              <1%   
  • TickTask: the task printing this statistic (once every 5 seconds)
  • IDLE: the idle task, when nothing else is running
  • 5DofTask: the task calculating the attitude (Kalman)
  • ControlTalk: the task calculating the PID control algorithms (50Hz) and the navigation (5Hz)
  • GpsTask: the task parsing the GPS strings (5Hz)
14 June 2009, 13:48 | Link | Comments [6]

Autopilot HILS demo

I’ve been working on 2 things lately (past few months, I didn’t have a lot of time in the last few weeks):

  • New autopilot module
  • Glass cockpit framework

This demo combines both of them:

  • Simple waypoint editing in the first seconds on the video
  • KML file viewing
  • Uav simulation: the navigation and control is done on the autopilot module. Sensor data comes from a simulated airplane model on the PC, servo positions are sent back to the PC. In manual mode, the autopilot module forwards the inputs from my RC transmitter. In autopilot mode, it will circle the home position (I should tune it better).

This HILS (Hardware-in-the-loop simulation) idea came to my mind after seeing Jordi’s great demo.

Technologies used:

  • Microsoft Virtual Earth for the maps (I also have a class for Google maps, but Google doesn’t seem to like us ripping their tiles).
  • WPF (a .NET 3.5 technology) is a graphics framework that does most of the rendering on the video hardware (not loading the CPU).
  • C for the dsPic on the autopilot module
  • General C#.NET for the airplane modeling
  • The windows application is completely OO. The view area consists of layers, all deriving from a base layer class. All layers have a model too. When the workspace is saved, the models are persisted to disk. This pure OO approach makes serveral transitions easy. For example I can switch between a .NET autopilot or a hardware autopilot class without affecting any other code.

11 January 2009, 20:18 | Link | Comments [1]

New flight tests

Today I did another flight test in very bad weather (actually my car got stuck in the mud yesterday while testing…). I also wrote a tool which makes it very easy to download the logging from the autopilot, and save it as XML (for later use) or KML (for Google Earth). The dataset viewer allows easy copying to Excel.

I was surprised to see how accurate the GPS height (from the EB-85 module) is, especially when it has 9 satellites tracked:

This is how the logging tool looks in it’s current stage:

13 December 2008, 16:41 | Link | Comments [8]

First logged flight

I finished migrating all my hardware-related code from my old autopilot to my new one. The most important new feature for me is datalogging (how could I ever live without it). Data is logged in a binary format on a dataflash chip.

The flightitself was manually and it’s only purpose was to test the datalogging feature.
It works! I was suprised to see how accurate the EB-85’s GPS height is. When I make a flight together with the barometer I’ll post a comparison between those 2 heights.

Download KML file

10 December 2008, 19:46 | Link | Comments [3]

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