Hello Heinrich,
very interesting point you have here.
Have you made any experiments about
vibrations with fuel engines? Typical gas engines may produce annoying vibrations
even if silent blocks are installed in the engine block as long as I understood
from people using this kind of aircrafts.
The flight duration of a quadcopter is
at most one hour as long as I have seen by internet and typical flights are
below 30 minutes. But if a quadcopter was going to still for more than 6 hours,
also the same IMU would be sufficient for insuring the right attitude
determination?
Why if only matters the quality of the
algorithm or the filter, in civil aviation, military systems and space crafts
use so expensive (hundreds of thousands dollars) inertial sensors if a fifty
bucks IMU can be equally efficient?
Anyway, as Hector suggested, integrating
the ADIS16488 IMU into paparazzi would be a positive evolution for integration
of any other AD sensor because most of them use the same protocol. So even if
at the end, it is proved that the integration of a high end IMU does not
improve so much the overall behavior of the autopilot, a whole new brand of
inertial sensors would have been added into paparazzi integration.
Coming back to my first question, there
is an "easy start" for integration of this IMU other than creating a
new module? I think that reusing some existing module may be more efficient in
creating the source code.
Best regards,
Mauro.
From: address@hidden
[mailto:address@hidden On Behalf Of Heinrich Warmers
Sent: domingo, 17 de febrero de
2013 17:52
To:
Subject: Re: [Paparazzi-devel] New
IMU in YAPA
Hello,
what is the reason for hi-end IMU's on the yapa ?
When i measure the vibrations on my multikopters i get levels of 0.4 g .
The rate sensors are not so sensible for vibrations since modern have
vibrations frequencies over 20kHz..
The vibrations have most first an second orders of the revolutions of the
propellers when you generate a spectrum.
A good pressure sensor with 24 bit resolution save the problems with the
altitude measurement of the GPS (Wrong values up to 80m if roll angles >
70°. are flown). When i calibrate the ID500 after power on i reach a bias value
of 0.3 to 0.5 °/s with the HB-mini.
So the cheap rate sensors build not a problem. The MPU6050 cost about 7 Euros
1-2°/s and fly quadrcooters and normal wing excellent.
The problem is the filter. The DCM filter was the first filter in
paparazzi witch estimates the centripetal forces. With this filter you can fly
helixes and circles as long you want. A improvement for implement
magnetometer values and offset angles would be fine.
To make a true INS you need a FPU and a closely coupled GPS and about 3-5
years of time to write a new dissertation of sensor fusion.
And the result ? To have true values for 20 seconds instead of 4?
Please think first on the near problems 1. save fly with a GPS lost. 2. filters
for the acceleration measure values. 3. true altitude measurement without GPS
3. true airspeed measurement 4. damping the vibrations etc.
Regards
Heinrich Warmers
Mauro Garcia Acero schrieb:
Hello everyone,
After some discussion with TU Delft
people, I will try to integrate the new ADIS16488 from Analog Devices into the
YAPA in order to verify the behavior of paparazzi with a high end MEMS IMU:
<From the AD site>
6°/hr in-run bias stability
0.3°/√hr angular random walk
0.01% nonlinearity
Because this IMU communicates through
SPI port, do you have any suggestion about how could I go quicker in the
development of the new module? I was thinking to reuse one existing IMU module
already communicating through SPI. But I have just begun to analyze the doc of
the web site, so, I'm open to any kind of possibility.
Thanks in advance,
_______________________________________________Paparazzi-devel mailing listaddress@hiddenhttps://lists.nongnu.org/mailman/listinfo/paparazzi-devel