Re: [Paparazzi-devel] ArduIMU and Tiny autopilot continued

[David Conger]

Hello,

Just an update so I thought I would extend this thread for others following. I 
was able to power all servos from the BEC. Only the PPM wire from the autopilot 
goes to the servos. Ground and power to the servos comes from the BEC now. 

So, I was able to fly. However, during sustained turns the autopilot commanded 
a sharp roll which I was able to recover from. It is consistently doing it. 
Also if the autopilot starts level it tends to stay level. However if you 
engage AUTO2 while the aircraft is not level it does not recover well (or at 
all). 

I realized after viewing this video: 
http://www.youtube.com/watch?v=H1rGYIDLKIE&list=ULKKPsIyq1E8Q&playnext=1 that I 
am using something different. That video was using the 6DOF razor which is just 
a sensor board. So the DCM code must be running on the autopilot in this case. 
In my case with the ArduIMU the attitude information comes from the ArduIMU. So 
if it's incorrect the autopilot is unaware. 

Chris from DIY drones seems surprised at this behavior and claims hundreds are 
flying with this IMU and the latest IMU running the same code. I'm not sure how 
it's possible but believe him. 

Did I miss something? I have a video showing the attitude information is 
correct on the ground. However in flight it simply is failing to stabilize my 
little Merlin aircraft. I am hoping maybe there is a tuning parameter I am 
missing someone can share with me to correct. 

I have not flown in weeks so I hope to get some new data soon.  However my 
questions are:
1. Am I supposed to be tuning the IMU somehow? If so how? 
2. The only video of a working example is not using an AHRS. Has anyone a video 
or proof of a Tiny+ArduIMU flying? Logs that can be replayed? Anything? I heard 
of a FunJet...can they share some more info to back up the claim and help me 
get flying. I have a FunJet BTW as well setup to go but don't dare try if the 
Merlin won't fly. 

Regards,
-David
On Nov 7, 2010, at 4:12 PM, David Conger wrote:

> Well, all is on hold. The plane flew well in manual but I found the 3-pos 
> switch was not working. It stayed in manual unless I turned off the radio. I 
> am using a T7CAP Tx and the same files that worked previously so this is a 
> mystery. 
> 
> -David
> On Nov 7, 2010, at 8:33 AM, Martin Mueller wrote:
> 
>> Hi David,
>> 
>> the attitude is only fetched with 15Hz from the arduimu, not sure why the 
>> authors set it to that. Maybe they can comment?
>> 
>> The setup seems to work in general but expect some more work until it can 
>> fully replace IR for small/agile planes. And of course Christophes IMU 
>> introduction applies.
>> 
>> Martin
>> 
>> On 04.11.2010 19:30, David Conger wrote:
>>> Awesome, thank you for clarifying. The Tiny211 I was not seeing GPS info 
>>> but I was also indoors so I will try closer to a window. The TWOG I will 
>>> connect a Paparazzi GPS to it.
>>> 
>>> Do you think the delay in the GCS display for attitude is normal? I guess 
>>> I'll soon find out. I'm trying hard to get this into a FunJet or Merlin. 
>>> Prefer the Merlin but there is so little room in there.
>>> 
>>> -David
>>> On Nov 3, 2010, at 10:59 PM, Martin Mueller wrote:
>>> 
>>>> Hi David,
>>>> 
>>>> it is in (3) of http://paparazzi.enac.fr/wiki/ArduIMU
>>>> 
>>>> "This Guide/Software is made to use the ArduIMU without separate 
>>>> GPS-Receiver and without Compass/Magnetometer. The GPS-Data is sent by the 
>>>> Tiny 2.11 over I2C to the IMU."
>>>> 
>>>> Martin
>>>> 
>>>> On 04.11.2010 06:30, David Conger wrote:
>>>>> All,
>>>>> 
>>>>> Some more questions...and observations.
>>>>> 
>>>>> What of the GPS? The ArduIMU has a connector for a GPS and the code in 
>>>>> the AHRS uses GPS to do yaw corrections I believe. I have right now the 
>>>>> GPS connected to the ArdduIMU but do not see messages for GPS in the GCS.
>>>>> 
>>>>> Are my observations correct that the ArduIMU is to be used without the 
>>>>> GPS or do I need two GPS to fly with. One for ArduIMU and one for 
>>>>> Paparazzi?
>>>>> 
>>>>> I'll take a photo of my setup tomorrow. I have a YouTube video up of my 
>>>>> current setup here: http://www.youtube.com/watch?v=9EFXRy11O7k
>>>>> 
>>>>> It seems a bit slow. I'll be curious to see if this is not an issue in 
>>>>> flight.
>>>>> 
>>>>> -David
>>>>> On Nov 2, 2010, at 9:16 AM, Martin Mueller wrote:
>>>>> 
>>>>>> Hi David,
>>>>>> 
>>>>>> with the Arduino debug plug pointing forward in flight and parts up the 
>>>>>> directions work ok for me. Maybe it is the earth horizon moving the 
>>>>>> other way than the aircraft?
>>>>>> 
>>>>>> Martin
>>>>>> 
>>>>>> On 02.11.2010 05:07, David Conger wrote:
>>>>>>> Hi Martin,
>>>>>>> 
>>>>>>> With your help I have a Tiny2.11 with an ArduIMU connected to the I2C 
>>>>>>> port. I followed the Wiki and am using your airframe suggested with the 
>>>>>>> exception that I also commented the ADC IR values and set the modem to 
>>>>>>> transparent.
>>>>>>> 
>>>>>>> Holding the IMU with the arrows on the IMU for X,Y,Z I see pitch in the 
>>>>>>> PFD is shown correctly. However the roll is reversed. If this was an 
>>>>>>> airframe with IR I would change the sign for: LATERAL_CORRECTION in the 
>>>>>>> INFRARED section. As expected there is no INFRARED section. I sure 
>>>>>>> could use a LATERAL_CORRECTION value to modify though :)
>>>>>>> 
>>>>>>> Is there a way I do not see to reverse the roll? Before doing this I 
>>>>>>> did upload the firmware in SVN for the arduIMU (as per the Wiki).
>>>>>>> 
>>>>>>> BTW, very cool to see IMU data and the PFD artificial horizon 
>>>>>>> responding to the IMU movements. Thank you for all your help so far. I 
>>>>>>> think I am close.
>>>>>>> 
>>>>>>> -David
>>>>>>> On Oct 30, 2010, at 11:26 PM, Martin Mueller wrote:
>>>>>>> 
>>>>>>>> Hi David,
>>>>>>>> 
>>>>>>>>> Thanks to the new notes I have a compiled airframe
>>>>>>>>> I would like to try the ArduIMU and followed the steps from the Wiki. 
>>>>>>>>> However there was no mention of this value:
>>>>>>>>>    <subsystem name="attitude"             type="infrared"/>
>>>>>>>>> ...and the IR_ values farther in..
>>>>>>>>> Can someone help. If I do  not have IR and am flying with ArduIMU 
>>>>>>>>> what becomes of those values? Removing them all brings compile 
>>>>>>>>> errors. Leaving them without any IR sensors won't cause issues?
>>>>>>>>> Would it be possible for someone who is flying with IMU to post their 
>>>>>>>>> airframe to SVN or in a reply? vn100 or ArduIMU or even Booz IMU.
>>>>>>>> 
>>>>>>>> you might try airframes/mm/fixed-wing/fw_ins_arduimu.xml. The infrared 
>>>>>>>> must be removed at the moment not to have two software parts update 
>>>>>>>> the estimator. Did you use settings/tuning_ins.xml as mentioned in (4)?
>>>>>>>> 
>>>>>>>> Martin
>>>>>>>> 
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