Strange behavior when RTH

[GuteFCO]

Hi everyone, yesterday I was flying and notice a strange behavior when I press the RTH button on the controller, the mavic was at 29m (95,8 ft) of IMU altitude and 49m (160,6 ft) from the home point, the Return-to-Home altitute was 40m in the settings, but when I press the button the Mavic start climbing without pauses and I cancel de RTH when it reach 65m (214,6 ft). I have a similar experience a month ago in very bright conditions, but at that moment the Mavic climb 10m, stop, try to return and detect the "obstacle" (the brigth ligth), then climb again and so on.

The user manual says:
"If Return to Home (RTH), including Smart RTH and Low Battery RTH, is triggered and the aircraft is further than 20 m from the home point:
1. It will return to home at the current altitude if flying at or above the RTH altitude.
2. It will ascend to RTH altitude if flying below it."

I take a look to the flight log (using https://www.phantomhelp.com/LogViewer) but I don't see any clue.

I use the DJI Go 4 app (4.1.4) and the firmware is the 0900.

Any idea of what happend? thanks.

 

[msinger]

I take a look to the flight log (using https://www.phantomhelp.com/LogViewer) but I don't see any clue.

Would you mind posting the link to your flight log?

 

[GuteFCO]

Would you mind posting the link to your flight log?

No problem DJI Flight Log Viewer - PhantomHelp.com the RTH start at 8m 36.3s

 

[msinger]

It looks like it encountered an obstacle on the way back to the home point (probably the sun shining into the front sensors), it stopped, and started ascending to try to climb over the obstacle. In such a case, the Mavic will continue to climb until it's over the top of the obstacle.

Later in the log, you can see the "Braking now! Return sticks to midpoints first" message when the Mavic was flying in the same direction. When high up in the air in a location where there are no nearby obstacles, that's an indication that the sunlight is shining into the front sensors.

 

[GuteFCO]

It looks like it encountered an obstacle on the way back to the home point (probably the sun shining into the front sensors), it stopped, and started ascending to try to climb over the obstacle. In such a case, the Mavic will continue to climb until it's over the top of the obstacle.

Later in the log, you can see the "Braking now! Return sticks to midpoints first" message when the Mavic was flying in the same direction. When high up in the air in a location where there are no nearby obstacles, that's an indication that the sunlight is shining into the front sensors.

I think the same, but in previous experiencies the Mavic stop, take a little step back, climb and retry, may be a slightly different conditions. My other worry is I don't get any alert or information of the "obstacle" in the app, no vibration and no proximity bars. either way I'm going to connect the Mavic to DJI Assistant and take a deeper look to the sensors information, thank you very much.

 

[msinger]

My other worry is I don't get any alert or information of the "obstacle" in the app

I've never seen messages like this in flight logs when obstacles were detected during RTH.

 

[GuteFCO]

I've never seen messages like this in flight logs when obstacles were detected during RTH.

Thanks for the feedback, I'm going to see the sensors info stored in the Mavic and try to find what happend, I'll post the results.

 

[GuteFCO]

I take a deep look to the log in the Mavic and the problemas was the obstacle avoidance, it detect a obstacle, here is a image from that.



Thanks for your answers and the clues

 

[msinger]

Thanks for sharing your findings!

 

[gnirtS]

Ive turned off obstacle avoidance in RTH for that reason. I quite often fly late evening due to work and quite often get imaginary obstacles from the sun.
I dont trust RTH-OA to actually fly home and not try to outclimb the sun. Plus the highest part of the entire country here is 60ft above sea level so its easy to set an altitude to not hit anything when it comes back!

 

[GuteFCO]

Ive turned off obstacle avoidance in RTH for that reason. I quite often fly late evening due to work and quite often get imaginary obstacles from the sun.
I dont trust RTH-OA to actually fly home and not try to outclimb the sun. Plus the highest part of the entire country here is 60ft above sea level so its easy to set an altitude to not hit anything when it comes back!

Thanks for the tip, I think the best practice is never relieve in the obstacle sensors in RTH and always ensure a good RTH altitude

 

[MoonstruckView]

I seem to have better luck with the RTH on the actual remote, rather than the phone. It may have nothing to do with your situation, but ever since I started using the hard button on the actual remote my RTH problems have gone away.

 

[charliesRig]

thanks for sharing IMO prolly need to set Visial forward avoidance to Hover Not go over or around

 

[GuteFCO]

I seem to have better luck with the RTH on the actual remote, rather than the phone. It may have nothing to do with your situation, but ever since I started using the hard button on the actual remote my RTH problems have gone away.

Thanks for the suggestipns , but I trigger the RTH from the physical button, may be in other conditions is better than the app.

thanks for sharing IMO prolly need to set Visial forward avoidance to Hover Not go over or around

I don't see that option, I going to search for it, thanks.

 

[WebMaximus]

Same thing happened to me today and now I realize why.

Thanks for the great info in this thread!