Hello,
I know lots of people with spare time but they don't have documentation. With these answers I can help them to work on the code. I did not realize the IR was optional with the Tiny1.1 and Razor example. Are there any examples with Paparazzi only hardware? Since the quality of the sensors matter I imagine using the Booz IMU would be more attractive to an open source project than using closed source IMU.
Thank you again for helping me with answers. They give me the ability to help bring more new talent to this project. When I get something flying I cab then demonstrate to the World and show them.
David On Sep 2, 2010, at 9:12 AM, Christophe De Wagter < address@hidden> wrote: Dear David,
The main thing missing is people that want to help and especially have time left. The DIYdrones and UAV Dev Board and HB Warmers code are basically the same. The UAV Dev board uses some hardware acceleration from the microchip. The DIY code is more generic.
There are several approaches to the IMU-based kalman filter. Many have done it. It does require some significant CPU processing so good programming is a must.
The quality of the IMU DOES matter. Lower drift, better resolution, high dynamic range make a difference.
Christophe
PS: you mentioned: "use DIY code and still use IR to fly": the code that Dr. Warmers committed does not need thermopiles if that is what you meant.
On Thu, Sep 2, 2010 at 4:48 PM, David Conger <address@hidden> wrote:
Hello,
One of their users flies a FunJet > 100mph, not in a straight line only, quite well with the DCM code. How is this possible from a project so new by someone with no experience with UAV before?
It should be noted that the code for the DIY is a simpler version of the orig. code from the UAV Devboard so maybe better results would come from code more like the UAV Devboard and not the DIY IMU.
I want to help, try out code, fly, ask programmers I work with to take a look... but I don't want to use DIY code and still use IR to fly fixed wing. I also can not afford a 2000.00 IMU. To me Booz is fine because anyone can assemble one or have one assembled from available plans or it can be purchased for about the same price as a VT100. I do not get the feeling having a 100.00 IMU will make all the difference. It's the lack of actually being able to do it or that it's not widely done with any IMU that seems to get the complaints from people I interact with. They simply point to the UAV Devboard and DIY for the examples.
-David
On Sep 1, 2010, at 11:34 PM, Christophe De Wagter wrote: Hello,
The AHRS works fine as long as there are no long-lasting kinematic accelerations. An airplane however does accelerate very often for a long time: for instance when making something as simple as a turn. This is a big problem for "Inertial/Magnetic-Only" AHRS. For quadrotors, as long as you hover or move slowly and always keep your nose in the same direction, these sensors are sufficient. For aircraft you NEED to compensate for kinematic accelerations. This is why either airspeed of GPS is required in order to make the filter stay within the +/-10 degree error range like thermopiles.
The code in the HW branch uses this type of filter as was written by diydrones.
If the Raisor IMU can be converted to accept GPS data, it could do the full computation. Once reliable attitude data is available, like you say: "it can simply be copied to the estimator variables"
If you run for instance the XSens Mti-G Module (with internal GPS and barometer for kinematic conpensations), that is exactly what happens.
-Christophe
On Thu, Sep 2, 2010 at 8:16 AM, David Conger <address@hidden> wrote:
Hello,
I took a look at the HW branch code today. Am I correct when I think the HW code in razor_imu is bypassing the DCM code on the Razor and just using the ADC outputs and then calculating the Euler Angles in the Autopilot. Then feeding them to estimator.
Since the Razor is an AHRS already can't the outputs from the AHRS just be fed to estimator directly? Just over SPI feel the Euler Angles output into: From estimator.c /* attitude in radian */
float estimator_phi; float estimator_psi; float estimator_theta;
I also see the wiring diagram in the HR branch shows IR sensors are still used alongside the Razor IMU. Is this because it's difficult to remove the IR code?
-David
Germar, Have a look at the post by Prof. Dr.-Ing. Heinrich Warmers on 23 July 2010.
He has tested a low cost Sparkfun IMU ( RAZZOR IMU 6DOF Razor - Ultra-Thin IMU) with the paparazzi hardware.
Contact hwarm or check out his branch in svn. I believe they have this IMU working with the autopilot already.
Buzz
On 09/01/2010 09:31 AM, Germar Walter wrote:
Hi, We are building a fixedwing Aircraft with tiny board. We want to replace the Thermopiles with a AHRS System. We have purchased the Sparkfun9DOF Razor IMU. On the IMU we are directly calculating eulerian angles via the code provided by http://code.google.com/p/sf9domahrs/source/list.
We have activated the SPI interface on the board to communicate with the paparazzi. Has anybody done something similar or knows how to use the angles for roll and pitch for stbilization? The code from the gyro.c only takes analogue measurements, but since We have a digital interface we don't want to convert to analogue just to convert back on the paparazzi.
cheers Germar _______________________________________________ Paparazzi-devel mailing list address@hidden
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