paparazzi-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Paparazzi-devel] ins subsystem


From: Loic Drumettaz
Subject: Re: [Paparazzi-devel] ins subsystem
Date: Mon, 23 Jul 2012 12:17:14 +0200

Hi,

I tried to add HFF filter a few times without success: the hovering becomes unstable. I suppose the HFF filter adds some delay to the position and speed estimation, leading to this unstable behaviour. I'm working in V3.9 branch, with lisa m V2.0 and ublox lea 6H GPS
Is it possible to tune the HFF filter parameters in order to improve the filtering, and maybe obtain better position and speed updates? I noticed the flag "USE_GPS_ACC4R" which adapts the filter coefficients to the GPS speed and position accuracy. Does it help? 
Or, does anyone have recommendations to tune the HFF filter, in particular:

ACCEL_NOISE

 R_POS     

 R_SPEED

Is it efficicient to specifiy the GPS delay in the filter, with "GPS_LAG" parameter? What is this delay for let's say, a Lea 6 GPS?


One the other side, I also understood that the IMU sensor filtering is affected by periodic frequency: https://github.com/paparazzi/paparazzi/issues/240. Is it the same problem for HFF filter?


Best regards

Loïc



Hi everyone,

For people working with the master branch (development branch), after commit https://github.com/paparazzi/paparazzi/commit/6b875f40dff3a61873e343cb6472b3cc0e2b357ca separated ins subsystem has been introduced for _rotorcrafts_.
This will allow to handle more easily several ins implementations.

What you need to do in your airframe file is to add this subsystem:
<subsystem name="ins"/>
With this configuration, you will have the vertical filter (float version) running with accelerometers and barometer, and the raw gps position and velocities for the horizontal part.
All airframe files in the git repository have been updated.

You can activate an horizontal filter based on gps and accelerometers by adding the line:
<subsystem name="ins" type="hff"/>
Please note that this code, while working, doesn't improve that much the estimation and should be completely re-written (anyone with an urgent need to do some kalman filtering ?).
You will also notice an "extended" ins subsystem, which is an attempt to properly use an other altitude information, like a sonar, to correct the barometer drift. This code is working as long as the flat earth assumption is correct (flying over obstacles will produce altitude step with a sonar) and that the input signal is not going crazy (which can be the case with ultrasonic sensors close to motors and propellers).
The road-map for this ins subsystem is to split the existing one into several, each corresponding to a given configuration (one of the vertical/horizontal filter or none). This should improve the readability of the code.
Do not hesitate to report issues.

Good flights to everyone

Gautier

reply via email to

[Prev in Thread] Current Thread [Next in Thread]