Precision Landing Help needed

Hi @ThomasSFL - if you could spare a moment please could you take a look a the attached log.

We are using a Pixhawk 2.1 Cube (With Quad 3.6.8) - No error messages from lidar or “bad vision positioning” and the logs show Heal as 1 and Tacq as 1 however the drone does not try land over the beacon.

Its annoying as I did have the system working 2months ago but it had to be stripped down and reset for something else…

Any help much appreciated!

Best regards,

Ben

Hi @ThomasSFL,

I have resolved the issues that I was facing. It was rather embarrassing actually. The camera was mounted back to front in the enclosure. The white button on the Pixycam should be facing the front of the vehicle. Setting PLND_YAW_ALIGN to 180000 (cdeg) resolved the issue. I was able to get 6 out of 6 prefect landing with PLND_EST_TYPE = 1 and PLND_ACC_P_NSE = 0.5. yesterday. For most of the landings the camera was right over the beacon.

I guess the issues I had with my other vehicles were due to a combination of poor tuning and/or camera orientation. Will be reviewing the photos from those tests to find out.

Thank you for your help.

SOLVED

Just to let you all know I managed to solve the issue from above; I found it to be a damaged connector on the Pixy camera board (Large black connector for I2C communication to Pixhawk); a couple of the header pins had very slightly lifted from the main board. I was able to re-solder the connector and with the following setup and parameters all worked well.

Setup:

Pixhawk 2.1 Cube Black
Arducopter 3.6.8
Mark One Beacon
Pixy Camera
Benewake TFMini LiDAR

Pixy camera is powered via the Pixhawk I2C port.

LiDAR is connected to the GPS 2 port (serial 4)

Parameters:

PLND_Enabled: 1
PLND_Bus: 0 (when set to -1 or 1 the bad vision position message would appear on the HUD)
PLND_EST_TYPE: 1
PLND_Type: 2

You can use parameter PLND_ACC_P_NSE to “tune” the stability of the drone in landing - with a S500 10” quad opted I found a value of 0.5 worked best.

Hopefully this will help any others having some configuration issues.

Hi @ThomasSFL!

I have Irlock working in precision loiter and land but for some reason when I do an RTL it does nothing with the IRLock, it lands as if there were no beacon there, any ideas??

Update to Arducopter 4.0.4-rc3 and re-test

Thank you Ill try with that one, what changed on this last version?

Check the changelog: https://github.com/ArduPilot/ardupilot/blob/master/ArduCopter/ReleaseNotes.txt or the github changes: https://github.com/ArduPilot/ardupilot/commits/Copter-4.0

Sorry I missed your message. Do you have a .log/.bin?

If you could help me with this problem, i would really appreciate it

Hello. So i actually managed to solve the problem by, resetting all the parameters to zero, then uploaded to 4.0.4 (from 4.0.3) and upload the same parameters back. Its weird but now it works great. Only isue is it is a little bit shaky during PLND. Should this parameter “PLND_ACC_P_NSE” be lowered?

Are you still having trouble with the large “swing” when first starting precision landing? I also am using a large drone with large propellers and it is rolling over all the way to 45 degrees then back as hard as it possibly can (which is very hard with KDE motors and 21" props 6S power) and it almost looked like it was going to flip upside down and crash.

Why is this Precision Landing so aggressive? if the copter is above the target a meter or less to one side there should be absolutely no reason for the copter to roll to 45 degrees in such an aggressive maneuver.

1 Like

It sometimes still does a big swing. It looks random. But it still in the first moment of detecting the beacon. I dont know why, but its very unpleasant

What is going wrong??? This is scary and dangerous and definitely not what I expected when I purchased IR-Lock. I am lucky I was able to get the drone back in one piece. See video and attached flight logs.

The drone has here+ RTK GPS and can nearly land back on the platform all on it’s own. It should only use the IR-Lock to guide it the last bit but it looks like the autopilot completely disregards the GPS, accels, all of it’s sensors and just relies on the camera alone. I have tried with multiple settings for PLND_ACC_P_NSE and this video was with it set to .5; the lowest authority for the camera.

I have also tried with Kalman filter on and off with the exact same behavior.

tlog file: https://ageagleas-my.sharepoint.com/:u:/g/personal/jimmy_underhill_ageagle_com/EVJ0sFHd8TJMv6eajJrXmJgBllwrF5x3fGXG9jWY9IgBIQ?e=9xj1x5

1 Like

For us, disabling the Kalman filter fixed the issue: You can read more about it here: https://www.ksp.kit.edu/index.php?link=title_info&oldTitleID=1000124383
On the paper: Robuste kameragestützte Präzisionslandung von automatisierten fliegenden Systemen (WARNING content in german)

With IR-Lock it‘s a mess. When I first used IR-Lock with Copter 3.4, it worked perfect. Smooth landings with precisions within only few cm.

Later, I think since Copter 3.6 or so, IR-Lock landings became unusable for me. In my case, nothing was changed in hardware or mounting of the sensor, I just upgraded the firmware. But from that time on, the behaviour of PL changed drastically.
The first correction movement, when the Pixy aquires the beacon is so aggressive that, depending on the payload, it seemed definitvly too dangerous to me to use PL any longer.

For me, none of the suggested changes of any parameters did ever solved the behaviour, so I gave up after some time.

And the aggressivness of the initial correction movement has nothing to do whitch the use of the kalman filtering or not.

1 Like

Really sorry to hear that :frowning: I read similar posts before but hoped the issues were resolved. This certainly does not behave like the IR-Lock videos on their website. I guess I will try once more to make it work and if not I will abandon it as well.

Do the devs not believe us that this is not working and is dangerous? I have read reports about the update from 3.6 that screwed this up going back several years and multiple firmware versions.

The simple problem is, that when the target is aquired, the copter accelerates with very high (maximum possible?) values to correct its position within just around 1m or so.Then, of course, nearly immediate, it brakes, also with very high angles. This leads to a totally unnecessary aggressive motion.

For shure, I believe this may be no problem with a Solo class small quad. But it is a unnecessary and risky issue on large machines (i.a. 1000mm hexa with low kv motors and larger props). In my case, especially with mid size cameras on gimbal as payload.

IR-Lock says, they have no influence in this, because this is the responsibility of the Loiter controller.
I never worked out which parameters can change this (if it is possible at all). Especially as this machine flies very well for years now in all other situations.

This behavior started with a firmware change, around 3.6 or so. When I first used IR-Lock PL with Copter 3.4, everything worked perfect.

i think you should check the takeoff point agian.

I totally agree with you, that this is a big issue for big drones.
Tested with Light big quad with U8II motors and 28" propellers.
The movements are definitely too aggresive and none of the parameters changes helped solve this for me.
I contacted IR-lock company and they told me, that in AC, there are only few parameters related to PLND only.
And that is the problem.
When we tried with small drone and 10" propellers, there was no issue there, because, you dont care if it leans a lot with such a small drone.
But it is really big problem with bigger drones.

Hello, could anyone help me with problem ?

Im testing landing on platform equiped with irlock. Out of 13 tries drone landed just fine in 9 of them. But after 9th landing it started ignoring IRlock. I switched to RTL, drone came back above platform as usual but during descent and landign phase it totally ignores irlock. It happend 3 more times after that and then i restarted whole system and everything went back working normally (all landings on irlock were successful after restart.).

Im attaching log files.

I checked logs as well but for me everythings seems to be normal. Every single time there was target acquired by irlock camera, but drone just ignored it and i dont know why (as i said, out of 13 landings, last 4 of them were unsuccessful.). In some of the last 4 unsucessfull landings i had to take control to avoid crash landing (drone was landing out of platform).

Thanks to everyone willing to help.

bin log

We are using lightware sf11 and pixy irlock.

@ThomasSFL