3.6.1 'RC FEEL' parameter no longer there in MP!

Now we are having to use 3.6.1 copter firmware I see that in ‘Basic Tuning’ the RC FEEL adjustment slider has been removed. This is a really useful adjustment tool as it reduces sensitivity of the the RC input making the aircraft less sensitive on the sticks without adjusting gains.

Can anyone tell me where this has gone, or why it has been removed? Can’t find it anywhere in any parameter lists.

If it is gone for good, then I would really like to know how to get back to 3.5.4 / 3.5.6 / 3.5.7 which were versions we were very happy with and that included this feature. The Load Custom Firmware options doesn’t offer any of these and versions on GitHub are not labelled in any intelligible way as far as I can see. Is there any reason why there can’t just be a folder with old versions in it. Easy to find with folders clearly and simply labelled for the different version numbers. Any chance this could happen?

This parameter is replaced with ATC_INPUT_TC .
See ATC parameters.

Options : 0.5 Very Soft
0.2 Soft
0.15 Meduim
0.1 Crisp
0.05 Very Crisp

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This prompted me to go checking because I have (had) RC Feel setup on a knob and the RC6 tuning channel.
Mission Planner is still showing RC Feel in the CH6 Tuning option.
Under full parameters, Tune the old options are still listed.
No mention anywhere of ATC_INPUT_TC in regards to tuning, although the parameter itself does exist of course.

I’ve also upgraded MP to latest Beta - no change

45 RC Feel is still listed in arducopter complete parameter list as the only thing similar and ATC_INPUT_TC doesnt appear as an option in MP and is not listed in the docs.

Does CH6 Tuning RC Feel now map to ATC_INPUT_TC ?
Or does ATC_INPUT_TC need to replace RC Feel on the list ?

Thanks for the comments guys!

Had a little play with ATC_INPUT_TC, only between medium and soft and can’t really see a difference. The RC Feel was perfect, small adjustments possible to best suit the aircraft and pilot skill level / taste, normally ran values between 35 at the least and 50 at most, and the difference over this range was clear and very helpful.
I’d really like to understand why it has gone. Someone has made a conscious decision to remove it, and it makes no sense as this is exactly the kind of thing many pilots need and use. If there is a good reason then fine, but can that info be shared with us? Or (as mentioned before) make the older versions of firmware more easily available so we can choose to use them if we want to. Please??? :slight_smile:

Alex, I believe the reason is to get ArduCopter FW compatible with all flight controllers who use ArduCopter even those very cheap ones.

Hi Shawn,

Sorry, we haven’t updated the wiki completely yet but I’ve added this to our wiki to-do list.

You should find that the ch6 knob option for RC_FEEL now actually updates the ATC_INPUT_TC parameter. I think you can set TUNE_LOW = 0 and TUNE_HIGH as 100 as you would have with RC_FEEL and it will tune using an appropriate range.

The issue with MP not being able to download older versions should be resolved soon I think. It’s certainly fixed in the latest beta. Perhaps @meee1 can say when the official version of MP will be able to install Copter-3.5.7 (maybe it already can?).

@Leonardthall is probably best placed to comment on why RC_FEEL was replaced with ATC_INPUT_TC. I don’t think it’s related to adding support for new boards but more likely because he felt it was architecturally in the wrong place (it was in the main vehicle code instead of the in the attitude controller) and the new method likely has some real benefits.

Randy, that makes more sense. I take back my guess comment above. Thank you for your explanation.

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Hi Alex,

0 Very Soft
25 Soft
50 Medium
75 Crisp
100 Very Crisp

Is almost equivalent to :
0.5 Very Soft
0.2 Soft
0.15 Meduim
0.1 Crisp
0.05 Very Crisp

The reason for the code change was the original RC_Feel parameter calculated the time constant using the formulae
input_tc = 1 / (2.0 + rc_feel_rp / 10.0)

As you can see rc_feel is an arbitrary variable with no meaning tangible meaning. Input time constant on the other hand has a clear engineering meaning that can be easily related to and explained. It is the time in seconds that the aircraft will take to reach 63.2% of the pilots commanded rotational acceleration.

What you are saying here is you could clearly see the difference when changing RC_Feel with a time constant of 1/5.5 and 1/7 but you can’t tell the difference between 1/5 and 1/6.6667. So maybe there is something else going on here.

I checked that Ch6 Tuning of RCFeel does in fact adjust ATC_INPUT_TC, although the range is a bit odd.
I’ll report back again with actual tune high and low values once we do some test flying.

Thanks to everyone for their comments and input, very useful information!

Thanks for clarifying the function. The aircraft is questions was a conversion of a customer built aircraft to Pixhawk, so we have no baseline for what this configuration would ‘normally’ feel like. Tuning was very solid, just felt a little twitchy on the sticks, and adjusting the ATC value seemed to have less than the expected effect. Not a major issue, and I am sure we will see something different when we use it on one of our own aircraft specs. It helps a lot to understand what is actually going on ‘behind the scenes’ when changing a value like this is order to understand what to expect from it, so thanks for taking the time to explain.

Not able to install 3.5.7 at the moment, at least we have not been able to. Hopefully that will change soon!

Cool, that makes sense. I am glad we could help!!

I finally got around to fixing the Ch6 tuning knob to give the desired RC Feel

Taranis radio, CH6 PWM range 982 to 2006
Fully counter-clockwise, 982 PWM = soft tuning
Fully clockwise, 2006 PWM = twitchy tuning
Centered = normal response

Tune High 575
Tune Low 5

Twitchy = ATC_INPUT_TC 0.1282
Normal = ATC_INPUT_TC 0.2040
Soft = ATC_INPUT_TC 0.4878

This worked OK for us with a 520mm quad, 3cell lipo… and so on. Obviously different craft are going to respond differently I suppose.
Anything lower that 0.12 was super twitchy like a small racing quad or something.

Somewhere between 3.6.8 and the upgrade path to 4.0.0 the TUNE parameter settings disappeared, changed back to 0.
What used to be TUNE_HIGH and TUNE_LOW is now TUNE_MAX and TUNE_MIN

To get my RCFeel on channel 6 knob I had to set
For ATC_INPUT_TC centre position to give about 0.22

TUNE is still 45 for RCFEEL in old terminology.