Vision failure everytime during takeoff

modaltb

As far as disabling the driver in the build you have:
/etc/modalai/voxl-px4.confg

You can comment out the last two lines to prevent the UART driver starting.

# ESC driver
# We start this even if there is a PX4IO module. If there is
# a PX4IO (M0065) module it will be plugged into the RC port
# and so this driver will output commands on an empty port.
#qshell modalai_esc start
#qshell mixer load /dev/uart_esc quad_x.main.mix

I just did a test and this made no difference in flight perf, but in the next release I will be checking for a param and only starting if the param is set:

My first flight I though I was reproducing your error, my Sentinel was flying awful and I had to put it down. I got our flight test team to make some tuning changes around the PID values for roll/pitch/yaw and we were able to fly after that.

So one data point out of this is, the default Sentinel tune is optimized for our UART ESC and doesn't work well with the VOXL IO / PWM escs out of the box likely.....

I will get these off the vehicle when I do some updates here in a bit and can share with you to see if that helps any.

Tamas Pal 0

@modaltb After diabling it, the quad is able to hover in stabilized mode. but it is going here and there uncontrollably and dangerously without any stick input and a bit of wobbling is still there. Any update?

modaltb

My next step is to share some PX4 params (pid settings, cutoff filters) that got my sentinel stable, but I need my team to validate before sending. I’m not clear if this will solve everything but will at least be a good data point. I’m hoping to get this tested tomorrow and will share

modaltb

@Tamas-Pal-0 ...

I still have nothing to report as far as finding root cause of something, after our tune tweaks I was up and going. I am still testing though for this use case to see if there's some edge case I'm not seeing, I'm just a bit slow with this debugging.

As far as sharing my params that got me flying, I don't even know if my approach here is valid, you have different motor/prop setup, and frames aren't identical, battery type?...

My lawyer told me to tell you "not to use these since we don't have the same setup and the author/developer in the post here isn't really a pilot so...." You've been warned by the lawyer!

# Pitch PID
1	1	MC_PITCH_P	5.5	9
1	1	MC_PITCHRATE_P	0.065	9
1	1	MC_PITCHRATE_I	0.150	9
1	1	MC_PITCHRATE_D	0.002	9
1	1	MC_PITCHRATE_K	1.0	9

# Roll PID
1	1	MC_ROLL_P	5.5	9
1	1	MC_ROLLRATE_P	0.065	9
1	1	MC_ROLLRATE_I	0.150	9
1	1	MC_ROLLRATE_D	0.002	9
1	1	MC_ROLLRATE_K	1.0	9

# Yaw PID
1	1	MC_YAW_P	2.0	9
1	1	MC_YAWRATE_P	0.15	9
1	1	MC_YAWRATE_I	0.10	9
1	1	MC_YAWRATE_D	0.0	9
1	1	MC_YAWRATE_K	1.0	9

################################################################################
# Noise management
################################################################################
1	1	MOT_SLEW_MAX	0.0	9
1	1	IMU_DGYRO_CUTOFF	30.0	9
1	1	IMU_ACCEL_CUTOFF	30.0	9
1	1	IMU_GYRO_CUTOFF	30.0	9

Checkout out noise management here... I've had some nasty flights due to cutoff frequencies.

Tamas Pal 0

@modaltb I have tried with your parameters. It is still the same. I am able to hover it but it is going here and there uncontrollably and a bit of wobbling is still there.

modaltb

Any chance you could post a link to a video of a flight to help us understand the failure mode even more? Sorry to this going, but we're struggling to find a smoking gun.

Tamas Pal 0

@modaltb I am using your parameters here and disbaled the modalai_esc driver. The video link is here
https://drive.google.com/file/d/1cbBXsEFMLztR7F1_en4i77F1ww4LbQ1t/view?usp=sharing

modaltb

OK thanks for the data. This is where I'm at now with my VOXL2 / VOXL2 IO setup sentinel, it's not super clean yet but but flyable for sure:
https://www.youtube.com/watch?v=1INto92k-v0

I'm getting our team to do a real tune and early this week and will post info.

Tamas Pal 0

@modaltb Thanks. which escs are you using for this?

modaltb

Hi @Tamas-Pal-0 ,

These are BLHeli 20A, should be similar/same as the ones from this kit: https://shop.holybro.com/spare-parts-s500-kit_p1251.html

Here's my setup:

Tamas Pal 0

@modaltb so, the problem is solved for you by tuning only ?

modaltb

On my setup yes that was all I needed to do, but we are still going to do a "full proper tune" on our S500 based frame (Sentinel dev drone) and I will confirm with you that we are getting performance as expected after this and share a video. Our flight test team will be doing that this week, thanks for the patience!!!