BTW The overal stability of the okto is great, I can even get my hands of the tx on calm days, only with the flightctrl installed at this moment.

Well still having problems with the alt hold to work well, it´s unstable and I don´t trust in it.

I changed all my 8 props to 1045 just to try with them, tried the standard parameters on it, and again working bad with the same behaviour that I´ve described before.

Today I took my first mk quad (this one get alt hold with real precision) and made the same test to both.

Holding the mk on a table I started motors with my tx, put them at middle gas (this is about what it takes for hovering on both) I swicth on the alt hold switch.

I made two conclusions,

1 air coming from propellers doesn´t seem to affect the height readings on both MK

2 Seems that the quad is handling better the gas line and it´s almost the same than the hovergas line, on the okto you can see that the gas line have much more peaks and doesn´t seem to be as good as the quad one.

Now the question is:

How can I improve the gas handling on my okto to look like my quad????

I attach you the both scope captures

quad capture


okto capture

Well looks like I´m writing here alone, but anyway, I still need help for solving this.

My recent tests show that while hovering without alt hold on if I turn on the altitude control (standard mode, not vario) it maintains the altitude pretty well, but if I give more throtle to raise the okto a bit and then leave the stick there, the okto starts to oscilate much.

any ideas?

Have you got a video that shows the problem?

Steve

No at this moment I don´t have any video to show.

The problem I think is easy to describe, I hover the okto manually, then I switch on the alt control, so the altitude limitation (standard mode) works really good. While still having alt hold on if I raise the gas stick to gain some height the okto will raise and reach more altitude, but as soon as it reaches this new altitude it would start to sink and it keeps oscilating above and below the new altitude setpoint very, oscilations are about 2m in total.

Is this in Vario mode or normal setpoint mode?

Steve

Normal mode

Hi,
can you post your parameters in a zip file? I can try loading them to my MK8 and see what happens.

regards

hi wavess
il do the same to on octo.not sure what you mean when you want to gain some height with set-point on.does it do the same thing in vario mode.if you put on alt hold and fly the mk around does it start to mess up the alt hold?
jamie

ddrake meinte

Hi,
can you post your parameters in a zip file? I can try loading them to my MK8 and see what happens.

regards

Ok I´ll put together a set for 3 or 4 flying modes with different parameters I´ve tried, but for example to get you an idea this behaviour is with stock parameters, and does not dissapear with all the other combinations on parameters I´ve tried so far.


Right now I´m using a coax okto with 8 turnigys 2213/22 and 8 EPP1045 props, firmware 0.76g on flightctrl, no mk3mag, navi or mkgps installed at this moment.

jamied meinte

hi wavess
il do the same to on octo.not sure what you mean when you want to gain some height with set-point on.does it do the same thing in vario mode.if you put on alt hold and fly the mk around does it start to mess up the alt hold?
jamie

On standard altitude mode you can go higher or lower than your current altitude just moving the gas stick up or down. For setpoint I say that while hovering manually and you switch on the alt control mk gets an altitude, for example 5 m (5 m is the actual setpoint), if you want to gain some height you just move up the gas stick until you reach the higher altitude you wanted, and stop moving up the gas stick at that point. I´ve been using the same way this alt hold mode since I have a MK back to 0.68 flightctrl firmware, and right now using this way too on my old MK without a single issue.

hi wavess
i know we have covered this before but my octo is auw now with the new pan mount on it 2950grams and my min gas setting is 145 when i activate alt hold it just sticks.these settings also work fine for vario as well.you might want to look at the z-acc parameter as well.just a thought you dont have any mixing going on in your tx do you?
as far as i am aware with alt hold(the old one)you should not be able to adjust the height that far above your set-point.when you activate it and give it a little more gas you should only be able to climb maybe another 1 meter.if i am wrong in this some one say because i do not want to give the wrong info.i will see if i can get my octo to do the same thing as yours tomorrow.
jamie

jamied meinte

hi wavess
i know we have covered this before but my octo is auw now with the new pan mount on it 2950grams and my min gas setting is 145 when i activate alt hold it just sticks.these settings also work fine for vario as well.you might want to look at the z-acc parameter as well.just a thought you dont have any mixing going on in your tx do you?
as far as i am aware with alt hold(the old one)you should not be able to adjust the height that far above your set-point.when you activate it and give it a little more gas you should only be able to climb maybe another 1 meter.if i am wrong in this some one say because i do not want to give the wrong info.i will see if i can get my octo to do the same thing as yours tomorrow.
jamie

you are right. In alt hold limit mode it is exactly like that.
I usually go on hovering manually, switch Alt Hold on and give a little more gas.
It should float around the balance point for about 20 cm plus or minus.

@wavess: are you still on 0.76?

hi wavess
from what you have explained i think you are trying to chase a setting that wont work for that alt hold mode.why it works on your quad i do not know.what you are trying to achieve is to set the octo alt set,then if you move the throttle even to ful it should not move it above the set point,however you can still decend as normal.if you then hit the gas it will only rise to the setpoint.i have once put the setpoint on a poti and you can adjust it like that.
jamie

jamied meinte

hi wavess
i know we have covered this before but my octo is auw now with the new pan mount on it 2950grams and my min gas setting is 145 when i activate alt hold it just sticks.these settings also work fine for vario as well.you might want to look at the z-acc parameter as well.just a thought you dont have any mixing going on in your tx do you?
as far as i am aware with alt hold(the old one)you should not be able to adjust the height that far above your set-point.when you activate it and give it a little more gas you should only be able to climb maybe another 1 meter.if i am wrong in this some one say because i do not want to give the wrong info.i will see if i can get my octo to do the same thing as yours tomorrow.
jamie

No I don´t have any mixing in the radio.

I´m used to fly with the altitude hold a lot, and always it has been possible to raise the level of the MK just increasing the gas stick, before H&I introduced the vario mode, the parameter that let you multiple your actual setpoint to raise higher was the gain rate that I remember that default value (0.74 and sooner versions) was about 2 (you could gain 2 times the altitude that you were when you switch on the alt hold).

I don´t know the reason why right now that parameter can´t be modified if you´re at the standard altitude hold mode.

Óne thing that I´ve noticed trying some parameters very similiar to yours was that the hability to climb more and fast with alt hold on with those parameters was very small.

The other thing that confuses me is that when I use this with almost standard parameters I´m able to climb to a higher level and the hover at this new altitude, on my old mk, and with my okto, the only thing is that with the okto the behavour is bad.

Could you guys try what I´m talking about with parameters similar to standard?

@ddrake yes I´m still using 0.76e

Seems that with standard altitude hold control is possible to exceed the setpoint. This is take from the wiki:

1. Height limitation control
When Altitude limitation is inactive the total thrust is proportional to the throttle stick position. The altitude limitation weakens the thrust if the current height exceeds the setpoint. The MK can exceed the setpoint, however only if the thrust is greater than the total weight thus making the MK gain height. Thus the stable hovering point is always above the setpoint. The deviation is proportional to the throttle stick value. The Setpoint can be defined in several ways. For example you could define the Setpoint to a fixed value which one could never exceed. Furthermore you could define one Poti (from 1 to 4) together with the binded channel on the radio transmitter and change the value during flight, while the parameter Verstärkung (gain / rate) is used to provide scale.
A further possibility is activating the check box use switch for setpoint , with which a poti should be likewise assigned to the Setpoint, so that one can switch the Altitude limitation on with the associated channel from the transmitter using a switch and the current height value as desired value is taken over at the same time.

Could someone verify which value is normal for acc-z after you calibrate gyros?.

My mk tool is reading about 700 from the main screen, with the kopter standing on the table.

@ddrake I made a .rar file with 5 different settings I´ve tried on alt hold.

you can download here:

http://rapidshare.com/files/364725557/mk_modes.rar.html

wavess meinte

@ddrake I made a .rar file with 5 different settings I´ve tried on alt hold.

you can download here:

http://rapidshare.com/files/364725557/mk_modes.rar.html

ok, downloaded. Will take a look and test on friday.

regards

P.S My Acc-z is around 1 in the record pics I have (0.74 fw) cannot test it right now but sounds definitely strange.

Ddrake, checked with my old MK the acc-z value and with other mk guys and the 700 value it´s normal.

Today I made what I think it´s the best test for the MK experts to help a bit here.

I made a video showing the behaviour on my okto, also at the same time and syncronized with the beginning of the video I capture a scope session showing the following data:

acc-z
vario meter
voltage
gas
hoovergas
hight value

please watch it here:

http://www.vimeo.com/10290278

and download the scope session here:

http://rapidshare.com/files/365514792/prueba_en_vuelo_alt_hold.csv

what I think after reviewing the scope session is that at aprox 41 sec when I give a little throtle to raise the mk and leave it there the gas that it´s aplying the mk for hovering it´s not correct at all and differs very much with the hover gas.

what do you guys think?

killagreg meinte

wavess meinte

Considering that my altitude hold is working really bad, I think is better just to hover with the MK manually and look at the "Hover Gas" value. Do you mean that this value divided by 4 is the value to place at "Min Gas" on the altitude tab?

I would not recomand to set Altitude Mingasso high. Its better to increase the hover variation from 5 to 7 or 8. That acts like a limit arounnd the hoverpoint for the altitute control output.

Sorry I didn´t see your answer till today. Why don´t you recommend to put the Hover Gas value divided by 4 at the "min gas" on the altitude tab? Is it because it turns into a very reactive MK?

I read Hover Gas 370, this /4= 92.5,

On my quad I read hover Gas about 410/4=102.5, right now on my quad I have set the Altitude min gas at 38 and it works really well, so I think that 92.5 for my okto is too much????

what is ur vimeo password