Smoothing-algorithm altered? (DJI Mavic Air)

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Cuspis
Posts: 17
Joined: Thu Aug 23, 2018 8:23 pm
Location: Germany

Smoothing-algorithm altered? (DJI Mavic Air)

Post by Cuspis » Thu Aug 23, 2018 10:17 pm

At the moment (version 1.4) I experience a lot of difficulties to gain smooth footages and I ask myself if the algorithm for smothing has been altered since one of the last beta-versions.

If I examine footages made on May 13th 2018 there is a feeling of gliding on ball bearings even if the flight direction of the drone alters.

Not so at the moment. Although the flight plan seems to be fairly rounded on my phone display (95 waypoints, curvature 3, length of the flight path 760 m in a closed loop) the drone performs jerks as in a wind turbulences (in absence of those in reality) at every small change of flight direction. The jerks are not compensated by the gimbal! During the whole loop the gimbal was ment to look automatically at one single POI in the middle of the loop (similar situation as in May with much better results).

I am really disappointed at that!

In combination with these observations I experienced in the footage a kind of small saccades (like an older stepmotor) at every waypoint if the waypoints are not so tight-spaced because of a smaller number of wp's or a longer distance to fly.

In my opinion the movements of the gimbal are actuated too discontinuously compared to former motion-layout.

Cuspis
Posts: 17
Joined: Thu Aug 23, 2018 8:23 pm
Location: Germany

Re: Smoothing-algorithm altered? (DJI Mavic Air)

Post by Cuspis » Fri Aug 24, 2018 1:36 pm

In addition to my last sentence:

The Mavic Air has an excellent built in capability to keep drone movements away from the gimbal as the final step of drone- and camera-steering.

I could imagine that the DH-software overrides this in some degree so that the drone cannot keep the gimbal totally steady.

Maybe that (in a kind of timeline) the DJI-software must be the very last factor to influence the gimbal in a chronological sequence of software-inputs to the drone.



By the way: In former versions there was the possibility to slow down the drone in narrow bends by aplying a check mark while smothing a flight plan.
But I cannot find it anymore.

Martin
Posts: 150
Joined: Wed Mar 28, 2018 4:47 pm

Re: Smoothing-algorithm altered? (DJI Mavic Air)

Post by Martin » Sun Aug 26, 2018 4:04 pm

Cuspis wrote:
Thu Aug 23, 2018 10:17 pm
At the moment (version 1.4) I experience a lot of difficulties to gain smooth footages and I ask myself if the algorithm for smothing has been altered since one of the last beta-versions.
We have not altered the smoothing algorithms, but it might be that there was some change within the new DJI SDK or newer firmware that affects the flight behavior of the Mavic Air.
Cuspis wrote:
Thu Aug 23, 2018 10:17 pm
If I examine footages made on May 13th 2018 there is a feeling of gliding on ball bearings even if the flight direction of the drone alters.

Not so at the moment. Although the flight plan seems to be fairly rounded on my phone display (95 waypoints, curvature 3, length of the flight path 760 m in a closed loop) the drone performs jerks as in a wind turbulences (in absence of those in reality) at every small change of flight direction. The jerks are not compensated by the gimbal! During the whole loop the gimbal was ment to look automatically at one single POI in the middle of the loop (similar situation as in May with much better results).

I am really disappointed at that!

In combination with these observations I experienced in the footage a kind of small saccades (like an older stepmotor) at every waypoint if the waypoints are not so tight-spaced because of a smaller number of wp's or a longer distance to fly.

In my opinion the movements of the gimbal are actuated too discontinuously compared to former motion-layout.
Can you send us the flight plan to support@droneharmony.com? I'd like to test something similar outside with our own Mavic Air. See if we can reproduce the behaviors and find a solution to it.

Martin
Posts: 150
Joined: Wed Mar 28, 2018 4:47 pm

Re: Smoothing-algorithm altered? (DJI Mavic Air)

Post by Martin » Sun Aug 26, 2018 4:09 pm

Cuspis wrote:
Fri Aug 24, 2018 1:36 pm
In addition to my last sentence:

The Mavic Air has an excellent built in capability to keep drone movements away from the gimbal as the final step of drone- and camera-steering.

I could imagine that the DH-software overrides this in some degree so that the drone cannot keep the gimbal totally steady.

Maybe that (in a kind of timeline) the DJI-software must be the very last factor to influence the gimbal in a chronological sequence of software-inputs to the drone.
DH sends basically a sequence of waypoints with the gimbal and yaw angles to the drone. This together with a "flag" on how DJI shall choose to interpolate the flight path along the waypoint is the handover from Drone Harmony to DJI's control algorithm. After that it is the DJI "black box" that takes over control on how the drone will actually perform the flight path.
Cuspis wrote:
Fri Aug 24, 2018 1:36 pm
By the way: In former versions there was the possibility to slow down the drone in narrow bends by aplying a check mark while smothing a flight plan.
But I cannot find it anymore.
Yes, we used to have this quite some time ago. We were not happy with the results of that and thus decided to remove it. Your input makes me think that it would probably a good thing to revisit the whole smoothing again within one of our next updates. There is also request for manual input on speeds at each waypoint, could fit together nicely. Let's see..

Cuspis
Posts: 17
Joined: Thu Aug 23, 2018 8:23 pm
Location: Germany

Re: Smoothing-algorithm altered? (DJI Mavic Air)

Post by Cuspis » Sun Aug 26, 2018 8:45 pm

Martin wrote:
Sun Aug 26, 2018 4:04 pm
Can you send us the flight plan to support@droneharmony.com? I'd like to test something similar outside with our own Mavic Air. See if we can reproduce the behaviors and find a solution to it.
Of course. But can you please explain to me, where I can find the desired file in my phone? (By E-mail, PM or in this forum to enlighten other users too.)

Are you interested in the corresponding footage? But the upload will contain nearly 2 GB of data.


Martin wrote:
Sun Aug 26, 2018 4:09 pm
DH sends basically a sequence of waypoints with the gimbal and yaw angles to the drone. This together with a "flag" on how DJI shall choose to interpolate the flight path along the waypoint is the handover from Drone Harmony to DJI's control algorithm. After that it is the DJI "black box" that takes over control on how the drone will actually perform the flight path.
Thanks for the explanation what DH does. Before that I supposed, DH itself is processing the interpolation too. Maybe the "flag" or the way it is interpreted by DJI has changed.

Later on I'll try to find out if a smaller (!) number of waypoints has an positive effect on flight path smoothing by reducing the calculation load in the drone's own computer.

Martin
Posts: 150
Joined: Wed Mar 28, 2018 4:47 pm

Re: Smoothing-algorithm altered? (DJI Mavic Air)

Post by Martin » Mon Aug 27, 2018 4:45 pm

Cuspis wrote:
Sun Aug 26, 2018 8:45 pm
Of course. But can you please explain to me, where I can find the desired file in my phone? (By E-mail, PM or in this forum to enlighten other users too.)
If you have your flight plan loaded (on the right) you can Import&Export -> Export State. This will export all what is currently in the state (areas, buildings & flight plans) into a .dhm file which can be shared.
Cuspis wrote:
Sun Aug 26, 2018 8:45 pm
Are you interested in the corresponding footage? But the upload will contain nearly 2 GB of data.
No, we'll try to reproduce the behavior with a similar flight on our end and see what we can do to improve.

Cuspis
Posts: 17
Joined: Thu Aug 23, 2018 8:23 pm
Location: Germany

Re: Smoothing-algorithm altered? (DJI Mavic Air)

Post by Cuspis » Mon Aug 27, 2018 7:39 pm

Sorry, but the actual version of DH (1.4.1) does not provide genuine data export into a file (only WiFidirect, Bluetooth and e-mail).

But all these offered options are not available with DH in my "only-fly"-cellphone.

If I could store/export a file with the flight plan into a folder of the phone, it could be mailed to you via USB file transfer by my desktop-PC.

Martin
Posts: 150
Joined: Wed Mar 28, 2018 4:47 pm

Re: Smoothing-algorithm altered? (DJI Mavic Air)

Post by Martin » Sun Sep 02, 2018 3:48 pm

Cuspis wrote:
Mon Aug 27, 2018 7:39 pm
Sorry, but the actual version of DH (1.4.1) does not provide genuine data export into a file (only WiFidirect, Bluetooth and e-mail).

But all these offered options are not available with DH in my "only-fly"-cellphone.

If I could store/export a file with the flight plan into a folder of the phone, it could be mailed to you via USB file transfer by my desktop-PC.
Android determines what sharing options you have. In order to store it into a file, you need to have a file explorer / manager program installed. I personally use fX explorer.

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