Servers by jDrones

Dual-motor tailsitters


(Luciano - Tecnodrone) #1299

Would know dier how do I configure the elevon outputs and motors for firmeware prior to 3.8?
I want to use 3.7.1 to be able to use the QGroudControl on the Android mission planner.


(Luciano - Tecnodrone) #1300

Would know dier how do I configure the elevon outputs and motors for firmeware prior to 3.8?
I want to use 3.7.1 to be able to use the QGroudControl on the Android mission planner.


(lorbass) #1301

I will pay attention. The log shows, that in this strange Roll the Param I was immediatly at I_MAX (3000)

Sometimes in a log the Value PIDR_I is during the whole test Zero, even Roll_I is set to 0.4.
P and D shows the correct values.
If this wrong I Value is then used for control, no wonder about bad results or interpretations.
Here in this Pic the RLL2SRV_I is set to 0.4, RLL2SRV_IMAX to 3000.


(letpi) #1302

@lorbass
Sorry, I don’t understand what you mean with the graph.
This is how I understand the integrative I term. If I am wrong I hope someone will correct me. I is used to cope with a plane out of trim. When your aircraft is well balanced and well trimmed you don’t need I and I log should be around zero all the time. I is built from an attitude error over time. I needs time to increase and also time to decrease. The time needed to decrease is critical when the plane attitude is changing rapidly after a bad event or if you are close to the ground because the correction can be out of phase.
@palm369
I tried all FF from 0.02 up to 0.2 and never saw any effect.
I_max limit the deflection of the control surface induced by I. Does I_max has an the effect on I building ? I don’t know. I believe the best thing to tune the plane controller is to rely on autotune as it always gave me good results.


(lorbass) #1303

The Log of the Wing Skywalker 6 with FW V 3.8.5 the value of RLL2SRV_I shows unrealistic Values.
Seems to be unrealistic, that a wing is so perfect balanced that I ist the whole time exactly 0.0.
Here the Log

And here a Log of my former Wing Caipirinha with FW Version 3.8.3
This looks like it would work.

And if this unrealistic Value is used in flight, he has no or wrong effect.


(lorbass) #1304

I have analized the Idea of Differential Thrust to avoid the Sideslip.
I set the Values for RUDD_DT_GAIN and KFF_RDDRMIX high to demonstrate the effect.
Surprised, it works but not as expected dramatic hard.
In the pic, the Wing was pressed dawn und up to provoc a correction.
But anyway, will attache Winglets and Rudder…


Click to enlarge the graphic.


(David Kaden) #1305

You see it at zero, because its the “i” of the plane PID controller, but your in the copter mode. You need to have a look at “PIQR_i”

In the log the:

  • “PID”-Messege contains the Plane PID Logging
  • “PIQ”-Messege contains the Copter mode PID Logging

Also pay attention that the Roll axis of copter mode is the Yaw axis of plane mode :wink:


(letpi) #1306

Unfortunately I can not help you, I arrived at this thread at the time 3.8.3 was released.


(David Kaden) #1307

You can use QGroudControl with any firmware version.


(Bill) #1308

Hi, did you already try larger elevons? I like your idea of using a skywalker X5. I also have one. It flies like a normal wing but VTOL would be very interesting because it is very hard to hand launch. But I am not sure if I should build a thrust vectoring unit or not. Almost 50EUR for one servo is a lot of money for such a project. And there are other parts to build and buy for the thrust vectoring unit. If it flies without thrust vectoring, I would like to try that first. Two motors and two ESCs are waiting for taking off :slight_smile:


(lorbass) #1309

Why do you know thats Kopter Mode?
Here the same pic from the beginning with the Mode FBWA.
(Last where a cutout)

And this is one log only as example, I have 15 without Values in PIR i.
P and D are OK.
Otto


(lorbass) #1310

Finally got it flying in fbwa.
May be due to the attached winglets and rudder, differential thrust or both together.
Still in save altitude, therefore small wing in the air.
Log File:
https://drive.google.com/open?id=1EG7mElQG8aE5067DZuLA3n7M_wRBMdc8
Video:


Params:
Test 6.param (16.2 KB)
Otto


(Pete) #1311

Hi all, I have put in another pull request. This shorts out the ‘pumping’ seen at high airspeeds in Qmodes. Essentially if your at a low airspeed it uses the VTOL gains and if your going fast it uses the plane gains.


(David Kaden) #1312

I don’t know for sure. In your latest log file there are values for PIDR_I in FBWA and no values in Copter modes.


(David Kaden) #1313

Here guys, may be useful:

PID Test Sheet.pdf (81.3 KB)


(lorbass) #1314

Good Idea is really usefull

Otto


(lorbass) #1315

Yes, in the new version of MissionPlanner they are now shown in the graph.


(letpi) #1316

https://discuss.ardupilot.org/t/plane-3-9-0-stable-released/31600

Among new features there is one concerning VTOL: improved VTOL flight code, with improved transition support and loiter
It should be applicable to tailsitter, however I don’t really understand what improvement has to be expected.


(David Kaden) #1317

(Pete) #1318

I have added Q_assist support to my latest pull request, here is a quick demo with then without it enabled.