"ALT" instead of throttle?

[bernieL0max]

Hey there,

I'm not sure if this idea has been discussed;

I'm interested to know if we can modify the code a little to modify the way the throttle is applied. I propose that I would fit a spring back onto my throttle stick so that it centres like the other axis.

Instead of controlling the throttle speed, it would control the TARGET ALTITUDE...

i.e. when armed the target altitude would be set to gound level, (or probably ground level -1m to be safe.), when I push my throttle stick forward it will proprtionally increase/decrease the 'target altitude', the microprocessor would then react by increasing/decreasing throttle until the target altitude is reached, and then modultae the RPM to maintain that altitiude as long as the stick remained centred.

what do you think?

Matt

[matbogdan]

Hey there,

I'm not sure if this idea has been discussed;

I'm interested to know if we can modify the code a little to modify the way the throttle is applied. I propose that I would fit a spring back onto my throttle stick so that it centres like the other axis.

Instead of controlling the throttle speed, it would control the TARGET ALTITUDE...

i.e. when armed the target altitude would be set to gound level, (or probably ground level -1m to be safe.), when I push my throttle stick forward it will proprtionally increase/decrease the 'target altitude', the microprocessor would then react by increasing/decreasing throttle until the target altitude is reached, and then modultae the RPM to maintain that altitiude as long as the stick remained centred.

what do you think?

Matt

I will be a good option if it wasn't so bad... Why we should change the expensive transmitter to do this job. This option will be great when we will have the flying thing flying by itself and we will only have to give instructions over a cellular phone connected to the drone over google map based application.

I personally do not think this is a good feature to deal with at the moment. GPS home and checkpoints navigation, better autolevel algo, Simple mode ... and the list can go on of the things that are more important.

[bernieL0max]

Thanks matbogdan

Many TX's can be quickly and easily converted between MODE1 and MODE2, typically by simply swapping a spring from one gimbal to the other, this also means that converting any of these TXs so that both sticks centre would be as simple as adding a second spring; no big expense there.


For aerial photo/video this would greatly simplify control/user-input/skill required for smooth stable flight. Currently altitude is all about managing the equilibrium of lift, weight, drag, momentum and various other contributing factors with your throttle, all-the-while having to react to compensate for external forces and altitude lost/gained during manouvers. If altitude was managed by the microprocessor it would make maintaining a consitent altitude far more simple and effective, and reaction times much faster.


Alternatively the system could be setup so that you configure an artificial 'ceiling' or MAX_ALT(?) prior to flight; then the throttle stick could be made to directly co-incide with a target altitude, in either a linear or log manner, from 0 throttle = ground-level, to 100% throttle = MAX_ALT. i.e. assuming my MAX_ALT is set to 100ft, and the correlation was linear, if I push my throttle stick to 50% I can be confident that the craft will rise from the group, climb to 50ft, then maintain that altitude through any manouvers I do...

Such an idea may also aid with ensuring that you stay within height requirements, i.e. a sporting organiser may allow you to film an event as long as you never fly lower than X feet over competitors, or laws/regulations may prevent you from flying above a specific altitude. If something like this was an option it would probably make sense to also set some constants such as MAX_CLIMBRATE and MAX_DESCENDRATE, and monitor and react to rate-of-change.


Does ayone know if altitude is measured accurately enough to make this viable? Is it calculated and dealt with in a way that relates to real-world measurements, or if it is a variable that is purely in the digital realm and unique that that craft/flight?

[mr.rc-cam]

Does ayone know if altitude is measured accurately enough to make this viable?

I believe it is possible to achieve the necessary baro precision. For example, the MikroKopter seems to have reliable alt-hold (perhaps an MK pilot can confirm this). But from my experience, obtaining reliable alt-hold with the MWC is a works in progress. And it needs more work.

[lucamacs]

I have a very long experience with Mikrokopter, altitude hold in not a strong point of MK.
With no barometer or GPS Mk has a very bad behaviour when you try to hover at a stable altitude, it will always go up or down, non matters if it is a quad, hexa or okto , and no matters the firmware release, I may say that it is in the DNA of the Mk.
Therefore with barometer used in "limit" mode (not "vario" ) things are much better but IMHO the result is far to be perfect, the copter the use quite a lot of energy to maintain the altitude limit and it is not a smooth operation but a kind of "battle".
I never use much the "vario" mode that is the purpose of the initial post.

My experience with Mwii is very little, but with the 1.9 firmware version I was finally able to find some good values for the altitude PID and now my quad is maintaining altitude in an almost perfect way and much better that any Mk I ever use (over 50 Mk).
What is really important to understand is that altitude hold works well ONLY if you engage the baro when you have reach a stable hovering and then you DO NOT touch anymore the throttle stick .
With "bad" parameters you will notice a different behavior for altitude hold going from Acro to Stable mode, when PID is perfect you will have the same behavior.

[mr.rc-cam]

I have a very long experience with Mikrokopter, altitude hold in not a strong point of MK.

I've always admired the demo videos from Holger showing outstanding alt-hold performance. So it's a bummer to hear that it really does not work as advertised.

[lucamacs]

Hello mr.rc-cam,
I'm not saying that in does not work, I'm just saying that the way how Altitude Hold is achieve IMHO is far to be optimal.
What has always made me sick is that with MK is quite difficult to have a "natural" altitude hold without using the baro switch , in theory when you find throttle position where motors thrust equal copter weight you should obtain a stable altitude(lets forget for a minute battery drop voltage over time) , with Mwii or TTcopter it is so with MK it will go almost always a little up or down.
I'm speaking for standard MK settings and radio controller without throttle expo curve (like Graupner mx16).
Perhaps with "vario" mode MK altitude hold is better but I am an old guy and I never use it prefering the "poti switch" mode where once activated you have to increase the throttle to allow MK to have enough command to operate, then it is not a smooth behavior.
For sure Holger will choose ideal settings for his copters and get best possible results.
If you look at the demo videos he shows often a quite dynamic and aggressive piloting style, funny because 90% of people that use Mk want a real smooth and calm copter for video shooting.

[matbogdan]

A simple mode tweak for this idea can be like this: When you powerUp you board it records ground level from the barometer and transform the normal throttle stick in altitude mode.
- stick lower position -> drone on the ground
- you can define over programming a maximum altitude (let's suppose 1Km)
- when you push the throttle stick to the up position, the multicopter will detect the difference in altitude you desire and altitude read and compensate. Like this you can allocate the throttle to work as a desired altitude input for the multicopter.