Re: [Paparazzi-devel] alt_hold - lisa_m + bmp085

[Eduardo lavratti]

Sergey, as you can see in my videos, the parameter are very fine tuned. When i use SONAR the rotorcraft hold position very solid.

I use foam around sensor.
The altitude swing indoor and outdoor.

The problem is not the precision of the sensor but the variation of pressure.
Sometime the altitude swing +-2 meter when the rotorcraft is stoped in the desktop.

Sergey, i using "I" parameter very low in this case (10~20)

The BIG question is, anybody using lisa_m ?
As i know, only Cédric use lisa_m.

i have mikrokopter, ardupilot1.0 with bmp085 and ardupilot 2 with ms5611.
The mikrokopter have rocksolid alt_hold as the arducopter 2.

The arducopter with bmp085 have some variation in altitude but it hold better than paparazzi.

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From: address@hidden
Date: Wed, 20 Mar 2013 09:56:19 -0300
To: address@hidden
Subject: Re: [Paparazzi-devel] alt_hold - lisa_m + bmp085

Just catching up on this… 

Barometers are also light sensitive, so changes in light intensity can cause rather sudden altitude swings.

The DJI Naza uses the MS5611. I've got one here installed on a TBS Discovery. When the left side of the controller unit

is not taped off with black electrical tape and the sun hits the bark, the altitude will change rather suddenly by 1-2meters.

When taped, the altitude is very precise within a decimeter of variance.

G>

On Mar 18, 2013, at 11:42 PM, Eduardo lavratti <address@hidden> wrote:

Hello friends,
after some months of hard work with paparazzi i can tell that my rotorcraft is flying 100% stable end navigation is almost perfect.

Yesterday i do lots of test using bmp085 and the altitude hold work with much variation.

for a test i installed a SONAR (matixbot) today and the altitude hold work very well but only after i disable barometer because INS add some kind of baro diff to SONAR.

After i configured GUIDANCE_V to get a good alt_hold using SONAR e enabled the BARO again.

The result is the same as a started the tests... the altitude hold with bmp085 has much variation.

Has any set to filter barometer ?
the aspirin 2 with ms5611 has a better alt_hold than bmp085 ?

I ask about bmp because i tested the last ardupilot model with ms5611 baro and altitude hold work much better than the old version with bmp085.

thanks ...

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