So,
The IMU_SENS and ACCEL_SENS are written in floating point.
And they convert the ADC values in SI physical magnitudes. Furthermore, the
real magnitudes are obtained via: real magnitude=sens*(adc value-neutral)
For the accelerometers, I have obtained the following
parameter:
SENS=
=0.0883
For the gyros with a similar
operation I obtain 0.0158663
But with these parameters, the IMU doesn’t react...it’s like
they are too small…
I have tested with different sens values, and have found
ones which make the PFD react more or less according to the inclinations I
apply…but after some seconds it looks like the IMU fixed another position
as zero…I have read something about gyro drift, but don’t know if
that is what I’m experiencing.
On other hand, I was watching only the ACCEL_RAW and
GYRO_RAW messages with the message agent. I have looked into messages.xml and
can see they should be the unscaled values, but I think I see the unscaled
values-neutrals(with sens=1)…but when I add a sens parameter different to
zero, instead of the unscaled values I see (I guess sens*(unscaled-neutral))…and
then I have also looked into the ap_downlink.h:
#ifdef
IMU_TYPE_H
#include
"subsystems/imu.h"
#define
PERIODIC_SEND_IMU_ACCEL_RAW(_chan) { DOWNLINK_SEND_IMU_ACCEL_RAW(_chan,
&imu.accel_unscaled.x, &imu.accel_unscaled.y, &imu.accel_unscaled.z)}
#define
PERIODIC_SEND_IMU_GYRO_RAW(_chan) { DOWNLINK_SEND_IMU_GYRO_RAW(_chan,
&imu.gyro_unscaled.p, &imu.gyro_unscaled.q, &imu.gyro_unscaled.r)}
#define
PERIODIC_SEND_IMU_ACCEL(_chan) { DOWNLINK_SEND_IMU_ACCEL_RAW(_chan,
&imu.accel.x, &imu.accel.y, &imu.accel.z)}
#define
PERIODIC_SEND_IMU_GYRO(_chan) { DOWNLINK_SEND_IMU_GYRO_RAW(_chan,
&imu.gyro.p, &imu.gyro.q, &imu.gyro.r)}
#else
#define
PERIODIC_SEND_IMU_ACCEL_RAW(_chan) {}
#define
PERIODIC_SEND_IMU_GYRO_RAW(_chan) {}
#define
PERIODIC_SEND_IMU_ACCEL(_chan) {}
#define
PERIODIC_SEND_IMU_GYRO(_chan) {}
#endif
And as far I as can understand, it’s like the messages
IMU_ACCEL_RAW and IMU_ACCEL are mixed…
I have tried changing in the IMU_ACCEL, the DOWNLINK_SEND
part to DOWNLINK_SEND_IMU_ACCEL (without the raw), and then I always see the
raw values in the raw message…the problem is that in the other messages
IMU_ACEL and IMU_GYRO I see “nad” or something like that, I can’t
remember exactly.
Sorry it’s such a long message…but I am still
trying to make the IMU run, and wonder if I have some hardware issue(I don’t
know if I should remove some resistors in the IMU-but feel that this is not the
problem), or if I am not well understanding the sens parameter, if calibrating
the IMU is not a simple question…
Next steps I’ll take will be testing the software
branches supposed to work with the IMU(when I first tried them there were
errors while compiling)and trying the calibration tool…I don’t know
which programs are supposed to be installed to run the script, only python? When
I run it by now, I get two nice pictures of my desktop, and nothing more.