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How to check "sensitivity" setting in flight logs?

samysys

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Hi all,

I am not proficient with the language of telemetry so I will just tell the story and hope that you understand the question I am asking.

Sometimes, my fellow drone pilots complain that their drones "drifted" and thus crashed with no sticks control. Whilst majority of the crashes are confirmed pilot error after reviewing the telemetry, I wish to dig further into the problem to see if incorrect sensitivity setting in the remote controller would contribute to the "drifting" phenomenon.

For most DJI drones, it comes with 3 standard control mode: Sport mode, Normal (aka P mode), Tripod (aka Cine mode etc). They each has default maximum ascend/descend speed, horizonal speed limit and rate of turn (angular velocity) etc. However, the setting can be adjusted in the “Gain & Expo Tuning”.

I have conducted several test flight (with Mini 3Pro) in different settings and did find that the drone may "drift" in some situation, especially when the “Yaw Smoothness” and “Brake Sensitivity” are adjusted, e.g.: when I do a full pitch followed by immediate release to neutral stick with a low Brake Sensitivity setting (value: 0), the drone will "drift" for 3-4 second before a complete stop in air (i.e. continue forward flying for about 15 meter); whilst if the Brake Sensitivity setting is set to high (150), the drone will stop almost immediately with a more drastic nose tilt. Similarly, with inappropriate Yaw Smoothness setting, the drone may continue to yaw after hands off the sticks.

Back home, I examine the dat and txt of the test flights. I found that the 4 relevant telemetry (RC.aileron, RC.elevator, RC.throttle, RC.rudder) were only showing how much I moved my stick (range: 364-1684, return value at 1024, regardless of the mode or sensitivity setting). Likewise, the mode (RC.mode) also only show if I was in N mode or S mode.

My theory is that if the sensitivity setting of respective mode is adjusted, it should somehow be kept/ reflected in the telemetry/somewhere. I just don't know where to find.

Does any one knows where/how to find related record? May be they are just kept for some models but not the others?

Thank you.

P.S. In case I did not explain myself clear in the above, this clips showed almost exactly what I tried to do in the test flight
 
I think you best bet would be to look in the DAT ...... but there may not be any record of it in either the DAT or the txt. The actual setting is most probably stored in the drone.
It might be possible to work out if it is recorded in DAT by, in one drone switch on, incrementing up or down the braking severity say every ten or twenty seconds then look in the columns of the csv of the DAT for that pattern. If you attempt this I would run a screen recorder on the phone or controller to give yourself a reference of when you made the changes.

However "drifting" applies to other situations as well e.g. side slip if you turn a moving drone but DO NOT apply aileron to counter the drone's original direction of travel. Think car on ice.
Drifting also applies where the drone's GPS and or VPS position holding is not great, then of course there is wind that may exceed the drone's capabilities to fight.
I have seen an otherwise rock solid mini 1 or perhaps 2 blown sideways when applying some combination of either or both full throttle and or max travel elevator, the same thing probably applies to forward/backward motion when is a head or tail wind and applying max travel aileron.

BTW, personally I think the use of maximum braking severity is a bad idea, it probably stresses the drone's air frame unnecessarily.
I would suggest it is better to pick a midrange setting, stick with that setting and learn to fly and brake the drone accordingly.
Changing the setting frequently is probably a bad idea too ...... the pilot may not remember the new setting ..... with possible dire consequences.
 
Last edited:
Hi all,

I am not proficient with the language of telemetry so I will just tell the story and hope that you understand the question I am asking.

Sometimes, my fellow drone pilots complain that their drones "drifted" and thus crashed with no sticks control. Whilst majority of the crashes are confirmed pilot error after reviewing the telemetry, I wish to dig further into the problem to see if incorrect sensitivity setting in the remote controller would contribute to the "drifting" phenomenon.

For most DJI drones, it comes with 3 standard control mode: Sport mode, Normal (aka P mode), Tripod (aka Cine mode etc). They each has default maximum ascend/descend speed, horizonal speed limit and rate of turn (angular velocity) etc. However, the setting can be adjusted in the “Gain & Expo Tuning”.

I have conducted several test flight (with Mini 3Pro) in different settings and did find that the drone may "drift" in some situation, especially when the “Yaw Smoothness” and “Brake Sensitivity” are adjusted, e.g.: when I do a full pitch followed by immediate release to neutral stick with a low Brake Sensitivity setting (value: 0), the drone will "drift" for 3-4 second before a complete stop in air (i.e. continue forward flying for about 15 meter); whilst if the Brake Sensitivity setting is set to high (150), the drone will stop almost immediately with a more drastic nose tilt. Similarly, with inappropriate Yaw Smoothness setting, the drone may continue to yaw after hands off the sticks.

Back home, I examine the dat and txt of the test flights. I found that the 4 relevant telemetry (RC.aileron, RC.elevator, RC.throttle, RC.rudder) were only showing how much I moved my stick (range: 364-1684, return value at 1024, regardless of the mode or sensitivity setting). Likewise, the mode (RC.mode) also only show if I was in N mode or S mode.

My theory is that if the sensitivity setting of respective mode is adjusted, it should somehow be kept/ reflected in the telemetry/somewhere. I just don't know where to find.

Does any one knows where/how to find related record? May be they are just kept for some models but not the others?

Thank you.

P.S. In case I did not explain myself clear in the above, this clips showed almost exactly what I tried to do in the test flight
It also occurs to me that if you simply want some form of reference material then you could, on a windless day, fly a set of calibration brakings from full speed to zero, one or more braking for each braking severity increment, then look at the h speed curves in csvview .
I do not know if either log directly records accelerations.
 
@samysys the settings you are referring to ,are how the drone responds ,to a given stick movment ,it can be an instant start responce ,and abrupt finish .or a more gentle start and stop responce ,the problem is altering the settings to find one that suits your style of flying ,is quite time consuming ,and requires quite small changes ,it is not an exact science ,and you really need to make a note of any changes you do between flights ,my advice would be to revert back to factory settings as a base point ,and choose a calm day to try out some tests, the settings are stored in the drones internal memory as far as i know
 
Thank you everyone for your reply.

I was just hoping the setting is somehow recorded in the telemetry, but I won't be surprise if it is stored somewhere.

I won't be worry if the maximum braking sensitivity. However, with low sensitivity setting, the drone may drift longer than the pilot expected and result in crash. As @old man mavic's advice, the default setting is where I would start every time.
 
However, with low sensitivity setting, the drone may drift longer than the pilot expected and result in crash.
If you set the joystick response so low that braking takes is very slow, that's not the drone drifting.
It's just slow braking.
If you set your drone to brake very slowly, it should be something that you'd realise and in the unlikely event that you crashed your drone due to slow braking, that would be piloting error.

I don't think I've ever heard of such a thing happening.
 
Thanks all again for your reply.

I thought about it when I was actually doing some test flights. I revisit the data and have the following finding:

  • when having a high brake sensitive setting, the braking was more drastic but the motor RPM or the tilt angle of the drone was more or less the same as full speed forward in sports mode. So, the stress on airframe/motors seems not to be a problem.
  • when comparing high vs low brake sensitive, the drone both came to complete stop within 1.5 sec (1.2 vs 1.4). However, the deceleration of low brake sensitive was slower and thus it covers longer "braking" distance, almost twice as long.

This is more like a academic/theoretic discussion. In real flight, I think I would keep using the default setting.
 
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