Suggestion - newbie training mode for mobiles

Discussions and questions about the Crazyflie Nano Quadcopter
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Joined: Tue Oct 04, 2016 8:40 pm

Suggestion - newbie training mode for mobiles

Post by LittleGreyCat » Fri Oct 07, 2016 11:18 am

As a recent recipient of a CrazyFlie 2 as a present, I am in a steep learning curve.

Putting it together was easier than I thought, but flying it with a mobile phone is proving to be a challenge.
The controller is very responsive but not intuitive, and the CF2 goes like the proverbial bat out of hell.

The first couple of flights were zoom bang what?

After some further reading I realised that the best way to start getting the CF2 balanced was to power it down, place it on a specific spot with a specific orientation, power up then just increase thrust until it lifted off the deck and then shot away and hit something.
Work out which direction it was going in, adjust the trim settings, place in original spot, power down and up (to reset stored orientation) then try again.
Eventually I could fly it a bit just using the throttle but it was still bouncing off the ceiling and the floor and down within a couple of seconds.

After some further reading I learned that people were programming the CF2 to raise off the deck and then hover.
If it can do that then why am I struggling to learn how to control it and failing most of the time?
Is this some kind of weird initiation where only the truly geeky who have spent most of their formative years (say from the ages of 3 to 30+) playing shoot 'em up games can master the controls? Others can just get frustrated and quit?
[Disclosure - I never got into computer games unlike my kids because I could never summon the patience to learn the keyboard controls to an intuitive level. Watching my son tapping away at the keyboard at high speed made me realise it was possible but required a level of patience that I didn't have. Likewise Role Playing Games - exploring and remembering 37 different steps just to get out of the first room alive never really floated my boat.]

So - a proposal for the mobile application (partly based on people learning to drive with dual controls, as often done in the UK).
[Note that this may already have been done but I haven't managed to find a forum topic describing it.]

(1) Start with a simple calibration application. Place your newly built CF2 on your chosen spot, and hit the 'calibrate' button. The software attempts to bring the CF2 up about a foot and into a hover. Depending on which way it drifts and how far, trim can be applied and the test repeated. If trim is not enough then changing the balance, checking the propellers and such stuff can be attempted and then the trim process restarted. With a bit of smart feedback from the software the fine tuning could be made easier; perhaps a note saying "to hold steady I had to add 2 points of forward trim" which can then be preconfigured. Eventually it will achieve a reasonably stable hover. This is a major achievement in itself. The CF2 is assembled and tested and ready for free flight!

(2) Learn the controls. There are 4 control actions and the interactions can be complex. If you don't have the learned reflexes then you may never be able to master all four because the duration of a training flight is so short. From (1) you already have the CF2 in a nicely controlled hover so you can learn one control at a time. Keep the throttle stable and enable one of the other controls at a time. Learn to go forwards and backwards. Learn to go from side to side. Learn to turn round and face another direction. Then enable two controls (one for each hand?) and learn to coordinate them. Once that is working then enable the third control - perhaps fly around the room at a constant height banking, turning, going backwards and forwards then returning to a hover. Free off the throttle control and use all four controls. Over gentle steps you have learned to fly!

(3) From (2) you have a way to learn any new interface, such as a game controller pad or joy stick. You can quickly adapt to any new interface.

This also makes me wonder how many people use the mobile controller.

Do most people buy the CrazyRadio and a joystick/controller (see previous thread) and fly using a PC?

Anyway, all this requires is some talented person with unlimited time to do the programming.
I am more than willing to be a tester. ;)

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Re: Suggestion - newbie training mode for mobiles

Post by derf » Wed Oct 19, 2016 12:42 am

Thanks for your suggestions.

You are right, it takes a bit of practice and patience to keep from crashing into things. Personally I found the Crazyflie to be quite stable from the start. Three Crazyflies did not require any trimming apart from making sure that the battery was centered.
I have to admit that I play(ed) video games and therefore might have an advantage with regards to using a game pad though.

One thing that I saw multiple times with first time pilots was the "off-or-full-throttle" approach, where people forget that this is a tiny quadcopter and little steering inputs are enough to keep it steady. Instead they only go full speed or no speed, hard left or hard right and so on while trying to control the quadcopter.

Regarding your proposals:

1. A calibration application would be nice indeed, although that is hard to do for a Crazyflie without knowing it's position. There is always more or less drift involved that could lead to a wrong trimming.

2. Learning the controls step-by-step is something that can be done. Throttle can be controlled (to a certain degree) with altitude hold mode. Roll and pitch need to be enabled from the start to compensate for drifting, but they could be dialled down to be less aggressive. Same with Yaw: it can be made very slow, to not interfere with your throttle axis (depending on your flight mode, throttle and yaw are mapped usually to the same controller stick).

3. For beginners I can only recommend to use a game pad (e.g. a Playstation or XBox controller) in favour of the touch interface on mobile devices, because it gives you a *much* better haptic feedback. And yes, there a ways to use a game pad also with your mobile device. :)

I will try to implement a "beginner mode" into the Android client, but can't promise a time frame.



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