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71
Vehicles - Other / Re: Bimode aircraft code changes
« Last post by trust on December 01, 2021, 06:37:36 pm »
Thanks for looking at this.
I've been compiling custom firmware versions of this, so it's more useful to me to have the code changes so I can recompile.
My main change was to include the call sign text in the display - I just hard coded it - the menu system didn't seen to work for this.
I've been making extensive use of the OSD to debug flight issues along with my multiple cameras onboard. I do have separate telemetry but the OSD is quick and easy to use.
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Vehicles - Other / Re: Bimode aircraft code changes
« Last post by jdl on November 29, 2021, 10:22:27 am »
The throttle display in the OSD doesn't seem to reflect the real throttle setting while in RTB - the value seems to stay the same as when it entered RTB. jdl know why this is?

OSD displays value taken from manualcontrolcommand_throttle (throttle channel from RC remote), this is how it was coded in original MinOPOSD. In autonomous modes it still reflects the Throttle stick position.

We would like to see actuatordesired_thrust (the FC computed and then applied thrust) instead, while flying automomous modes.

I've made the necessary code changes but had not tested them yet.

Give me the firmware number (or build options) you are interested in. I'll compile and upload the firmware.
73
Vehicles - Other / Re: Bimode aircraft code changes
« Last post by trust on November 26, 2021, 05:38:36 am »
Ah, good to know its doing what it's supposed to!
In the last test flight of the day, I tried going up as high as I could see and then RTB - it came back, but was so high I could still barely see it.
I checked the code - you have it almost right - here's the relevant statement:
   destDown = MIN(positionStateDown, takeoffLocation.Down) - destDown;
 Since the Z axis is negative, min is really max, and the - destDown ADDS the offset distance to the end point. So it ends up coming back to a point offset distance ABOVE the point where RTB as initiated.
I have offset set at 10m and sure enough - the plane climbed to a point 10m above the point of RTB start in every case.
That also explains why the motor would accelerate just after initiating - it needed to climb.
I suppose you could set the offset to a negative value, then it would come back lower, but that seems risky if you start too low. Better to go a little high.
What I was referring to about the yaw sound is when yawing right for example, right side motors go down in pitch, left side goes up. Easily discerned from just increasing/decreasing - like chords vs simple notes.
I've done very little flying with yaw set in manual mode (other than autonomous modes). Most of the time turns are done with mostly yaw so as to be flat and more efficient. No difference turning left or right that I can tell. Even sharp turns are usually done with just yaw, but if taken to an extreme (max "rudder", or max differential thrust), one wing tends to stall and drop - there you DO need to bank as well to prevent that. Having props on 4 wings tends to keep airflow and keep wings flying except in extreme cases.I have a switch on the xmtr which mixes some rudder when rolling which I normally keep on, so it generally always does some "rudder" when banking, but I almost always add rudder too.
  I also have my rcvr set to switch to RTB mode if it loses signal - haven't actually tested in the field but goal was if it got out of range then RTB would bring it back into range.
  One goal is to plan flights to go high spiraling up, then mostly glide back down, using the aircraft for wx sounding or mapping. I suppose this could be accomplished just as well with waypoints. But if it goes out of range, RTB would just make it hover way up high out of range till the battery depleted - not good. I guess the rcvr would have to be programmed to fly the waypoints if signal lost, or make a new RTB option mode that flies it back to home+offset.
74
Vehicles - Other / Re: Bimode aircraft code changes
« Last post by TheOtherCliff on November 26, 2021, 02:59:15 am »
At the 1:17 time in video 2 I thought I heard throttle changes, from differential throttle?  Telemetry of either/both of:
- StabilizationDesired Yaw (easiest to interpret) and
- individual output channels
will tell if you are getting adverse yaw, but if the code sets FW yaw to manual then this is not the issue.

Now that you mention it, my recollection of the RTB altitude is that it stays at the higher of:
- current altitude (altitude when RTB was engaged)
- RTB altitude
so that would explain why it does not come down during RTB.  This is done so you can fly a long way up a gentle slope, do RTB, and not have it dive into the trees.  :(

I discussed the opinion that (if above RTB altitude) it should descend diagonally from current altitude to get to RTB altitude just as it arrives at base.  At least this should be an option.  Your RC signal will generally not work without line of sight, and this is safe as long as you have line of sight.  Else if you fly up a very steep mountain to great height, and then do RTB, you may not even see it or hear it when it gets to base (over head and way up high), and at least it will take a very long time to come down (dead battery?) if you have it switch to landing mode then.  If descending diagonally, the code could descend much more quickly than the default 0.5-0.7 m/s of landing vertical speed, and do it more safely because it has good forward speed too and doesn't get in it's own downwash so much as coming straight down.  Of course the current "landing mode at end of RTB" could descend faster than the landing speed until it got down to RTB altitude, but again, then you would be coming fast straight down in VTOL and that is often not so good.

When doing sharp banked turns in ATTI, ATTI, MANUAL (to mimic RTB), does it do fairly steep banked 360 turns well (without using the rudder control, to mimic the way RTB does it) in both directions, left 360 and right 360?

Does it turn better one way than the other?  Cross trimming is often necessary to get it to turn equally left vs. right.  Trim any left - right difference out with the rudder trim, then use opposite aileron trim to make it fly level after that.  Example: If it always tucks the nose in and dives in left turns but levels out / rolls out of the turn when banking right then you need right rudder trim to stop that and probably some left aileron trim to offset the new rudder trim.
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Vehicles - Other / Re: Bimode aircraft code changes
« Last post by trust on November 26, 2021, 02:23:25 am »
Thanks for the suggestions.
I too hacked the throttle min/neutral/max settings along with the pitch min/neutral/max settings to get to this point. These actually were crucial in getting reasonably stable flight.
I have telemetry set up, so I can try taking some logs.
No, I don't think it is switched out of FW mode.
ST2 mode is ATT/ATT/Rate mode and works well now with the bigger front elevon. You definitely can bank to turn.
In reviewing the video again, I noticed that in all the times the plane turned away from the desired direction, it was after it had significantly pitched up - likely due to thermals or other lift. After the nose leveled out, it turned back in the desired direction. These might just be external forces trying to fight the turning. Fortunately it seems like the controls keep trying to move it in the right direction.
I checked the FW code- yaw is set to manual mode. I can tell its not changing in the videos sound - yawing is done with throttle differential and you can hear the combined up/down pitch shifts if a yaw control is happening at all.
I'm still puzzled as to why it seems to stay at the same altitude. The RTBAltitudeOffset is 10m - so it should be going to a point only 30 ft over takeoff.
76
Vehicles - Other / Re: Bimode aircraft code changes
« Last post by TheOtherCliff on November 25, 2021, 11:53:38 am »
My past testing of RTB generally started fairly high and I was satisfied that it maintained the desired altitude, but it's been a while, and I did tune my throttle / altitude settings before I was happy with it.  Also my attitude limits to get it to turn sharper.

There is an altitude PID and thrust limits.  In one case the throttle was oscillating with a period of many seconds and I just hacked the thrust limits min/neutral/max to get a reasonable flying speed.  This is not the right way to do it.

Throttle increasing in the beginning and then backing off sounds like it has achieved the desired altitude.  Fixed Wing adds throttle (not elevator, at least not directly) to climb.

I would suggest telemetry.  Record telemetry during a bad flight, and play it back while watching appropriate scopes to see what is happening.  Enable different telemetry or change reporting periods as needed and fly again.  Watch out to not send too much telemetry data and swamp the link.

Is it possible that it changed from FW to VTOL?  And maybe there are other code tweaks that need to be made to make the switch work well.  To narrow it down, I would mechanically lock it in either FW or VTOL and fly stock firmware to see if it has the same issue.

Do I recall there were some bank and yank questions with this?  Is your ST2 mode set up as ATTI, ATTI, MANUAL and working well in that it feels good when you bank and yank?

I think that having both aileron and rudder stabilized in FW could cause issues.  If you bank and yank without rudder, the rudder will fight you.  RTB does bank and yank without rudder.  This is why I leave rudder set to manual in fixed wing autonomous flight (I haven't examined the code to see if this does what I hope it does).  I would mechanically lock it into FW, disable rudder stabilization and see if the bounce back is gone.

In VTOL mode it doesn't yaw to point forward.  It just flies sideways if that is how it starts out.

Don't know why OSD throttle doesn't change.

You may want to message @JDL.  He may miss the reference if he doesn't read the post carefully.

Good luck!
77
General Discussion / Re: silent mode for LibrePilot-16.09_i686
« Last post by TheOtherCliff on November 25, 2021, 11:17:39 am »
Windows?  The NSIS installer uses the /S option to mean silent.  How to configure this?  Sorry.  Don't have a Windows box handy here.  Research the NSIS installer for more info.  :)
78
Vehicles - Other / Re: Bimode aircraft code changes
« Last post by trust on November 25, 2021, 08:52:52 am »
Been quite a while since last posting - back at work pretty non-stop so haven't had much time to work on the planes.
I've since rebuilt M24 with a larger front elevon - this significantly improved overall pitch stability.
Had a number of nice easy flights with it, so tried RTB again just recently. 3 test flights with 9 tests of RTB and all went pretty smoothly. Tried various positions, altitudes, angles to see how well it acted. Video links at end of this post.
Noticed a few things:
Perhaps this is due to its relatively fast flying speed, but there was very little altitude change from start of RTB to reaching point over home. I thought it was supposed to seek a fixed point defined in setup altitude over home.
The throttle display in the OSD doesn't seem to reflect the real throttle setting while in RTB - the value seems to stay the same as when it entered RTB. jdl know why this is?
Once or twice aircraft began a turn in the correct direction towards home, but then suddenly changed direction away from home, but then changed back. At 1:17 on part 2, it turns away for quite a while, turns back, then turns away again. Eventually gets back on track and returns. Bit of a nail biter there.
For the most part throttle would initially increase on initiating RTB, but then would back off. There was some surging in the whole process. Any thoughts on tuning to smooth the surging?
Here is a two part video with OSD from the Runcam on the first test flight.


79
General Discussion / silent mode for LibrePilot-16.09_i686
« Last post by rol on November 25, 2021, 08:43:51 am »
Hi all,

Do you know how to install LibrePilot-16.09_i686.exe in silent mode ?

We need to deploy this software with our system
80
General Discussion / Re: Custom Motor_Pwm_Rate
« Last post by TheOtherCliff on November 22, 2021, 08:43:31 am »
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