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Re: Space Shuttle - Development

Postby wlbragg » Tue Sep 27, 2022 10:06 pm

OK, I successfully removed the shadows from the CWS display and pushed the changed lightmaps. Hopefully the CWS display will look better in future videos in all lighting conditions.
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Re: Space Shuttle - Development

Postby GinGin » Wed Sep 28, 2022 4:20 pm

@wlbragg: At least it looks really nice in those conditions:

Image

@EatDirt: I have almost finished with the TAEM roll thing.
I did like with the pitch channel, I converted the initial roll commanded into a roll rate error. It is smoother for the AP and I will try to inject that into the diamond guidance.

What do you think to aim for a stable release version after that ?
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Re: Space Shuttle - Development

Postby GinGin » Fri Sep 30, 2022 12:38 pm

I pushed a commit for the TAEM roll channel.
Not much differences for the AP overall, smoother in some exotic conditions.
HUD diamond guidance is based on roll rate error and ADI error needle is still based on roll error but with a smoother logic.

@EatDirt: I dont test it with a joystick, could you tell me how it goes ?
Flickering should be less present.
We can still fine tunned the gains for the guidance deadband.
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Re: Space Shuttle - Development

Postby eatdirt » Sun Oct 02, 2022 4:03 pm

@EatDirt: I dont test it with a joystick, could you tell me how it goes ?
Flickering should be less present.
We can still fine tunned the gains for the guidance deadband.


Thanks Gingin. I've tested with 2018.3.13 and 2020.4.0, perfect navigation and 0kt wind. I have exactly the same pb, the HUD diamond is far too inside the HAC and one cannot fly the HAC following its guidance only. Am I the only one seeing this?

In fact, I do see know the circle predictor on SPEC 50 being more aggressive than before, it oscillates a bit inside and outside the HAC drawing. Dunno, for the circle predictor, I feel that the settings were better before, sorry :?

But for the inconsistency between the Hud diamond and the circle predictor, that must be a bug. It feels like the diamond marks a predicted step too much in the future! (I'll try to have a look to the code)!

Cheers,
chris.
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Re: Space Shuttle - Development

Postby GinGin » Sun Oct 02, 2022 5:46 pm

I will try to test it with a joystick.
I did well with the keyboard, and auto guidance is accurate.

The spec 50 predictor and diamond guidance are not linked. I didn’t touch the circle predictor. It is sensitive to lateral accelerations, I will have an eye on it.

The main indicators to follow in manual for the lateral guidance are: lateral deviation at bottom of PFD or top of the spec 50 display / Attitude error needles are fairly accurate too.
Diamond still need to be fine tuned.

What do you mean by far too inside the HAC?
The HAC radius is shrinking , so the spec 50 display might be misleading.
The Diamond has indeed a step in the further compared to the spec 50 display
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Re: Space Shuttle - Development

Postby eatdirt » Mon Oct 03, 2022 7:55 pm

What do you mean by far too inside the HAC?


I mean exactly as in the pictures of this post: https://forum.flightgear.org/viewtopic.php?f=87&t=35076&start=1365#p404561

I agree that with the circle predictor, the vert sit, you have more than enough to properly fly the HAC!

The pb is if you only try to "cage" the diamond, that's not going to work (while it used to work very fine). I'll dig into the code to understand better what is going on there (from the pictures mentioned above, it seems that the roll needle also wants too much roll).
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Re: Space Shuttle - Development

Postby GinGin » Tue Oct 04, 2022 7:15 am

Alright, I will have a deeper look there with my joystick
It is not cage, there are some dead bands. I will go for a proper lag filter or smooth fonction to take into account the difference in refresh rate between guidance (nasal) and control (jsbsim).
The thing is that ap is also flying those guidance cues, and follows the HAC with a great accuracy.

You can find the relevant code in hud.nas and TAEM.nas
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Re: Space Shuttle - Development

Postby wlbragg » Thu Oct 06, 2022 9:44 pm

Hum, you guys are getting me hooked again. I think even at its current stage this might be worth replacing the existing ISS?

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Re: Space Shuttle - Development

Postby GinGin » Fri Oct 07, 2022 11:38 am

@EatDirt: I pushed a commit for the HUD roll flight director. Back to bank error instead of roll rate error with previous gain.
Tell me how it goes. As bank error outputed by TAEM guidance is really different than the one calculated in present stable release version (mainly a shrinking HAC vs constant radius HAC), it might be tricky to find the correct gains to have a really smooth lateral HUD guidance. I found some interested docs about that though, I will have a look.
For now, I think it works ok enough. Waiting for your feedback :)


@Wayne: It looks really nice wow. That is a nice idea to push it on the dev branch. Looking forward to test it.
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Re: Space Shuttle - Development

Postby wlbragg » Sat Oct 08, 2022 6:07 am

How about this?
Image
That almost freaks me out in the simulation.
This is the ISS_2016 model from NASA, (as-is), I didn't look at the scale or anything. Just wanted to see if it would load.
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Re: Space Shuttle - Development

Postby GinGin » Mon Oct 10, 2022 12:45 pm

@Wayne: Frightening indeed :)
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Re: Space Shuttle - Development

Postby GinGin » Fri Oct 14, 2022 12:44 pm

I have started to work on some ECAL and contigency abort improvements for AP, especially after the Nz hold phase.
For the roll channel, an early Energy computation to have a steering towards an ECAL or Bermuda site during Alpha Transition phase.
For the pitch channel, it will be a kind of alpha modulation within min/max alpha based on our total energy.
An interesting reading about that: https://core.ac.uk/download/pdf/10556102.pdf

Not much guidance datas about that, a lot of inter/extrapolations for the Energy graphics (Similar to the TAEM one's but taking into account the higher mach of contigency aborts).

Also, I am working on a new DPS display called Ascent / Entry bearing (SPEC 54)
It was introduced during the last Update of the computers (OI-33).
Some informations at the end of the SCOM: https://www.nasa.gov/centers/johnson/pdf/390651main_shuttle_crew_operations_manual.pdf

I am focusing on the Entry part for now (OPS 6 and 3). Ascent is more complicated canvas wise.

Image

Image
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Re: Space Shuttle - Development

Postby eatdirt » Tue Oct 25, 2022 10:17 pm

I dunno what to say Wayne... :shock: 8) :shock: :idea: :!:

I am just so happy to have called you back on duty!

@Gingin, I'll give it a try, I've been busy with real life things...
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Re: Space Shuttle - Development

Postby eatdirt » Thu Oct 27, 2022 9:15 pm

Hi there,
@gingin, tested again the TAEM in CSS, really same problem for me :-/ (tested on both 2018 and 2020)

I have tried to understand what I do compared to the autoland. In fact, while transitioning to the HAC, the autoland is extremely aggressive, it banks like hell, overshoots, then undershoots, before finally getting close to where it should.
In CSS, I am waiting the autopilot and the diamond to say "turn into the HAC", but by the time I am slowly banking, the diamond guidance is always far and I am always lagging behind (unless I bank like hell, but then loose energy, the HAC shrink and etc...) It really looks like the diamond is far too much in the future?

Other things, here a merge request providing some files that fix the fallback model interior effects in the cockpit, these will be broken in 2020.4.0:

https://sourceforge.net/p/fgspaceshuttledev/code/merge-requests/42/

As suggested by Thorsten, these files have a suffix _next.eff and are currently unused. We will just have to replace the *.eff bu these when transitioning to 2020.4 (there is a bit of backward compatibility breakage in 2020.4 that will affect the Shuttle).

cheers,
chris.
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Re: Space Shuttle - Development

Postby GinGin » Fri Oct 28, 2022 2:50 am

@EatDirt: could you provide a short video with Auto on a bit before HAC interception ?
What is the entry HAC angle ? Are you always flying the same kind of TAEM ? I observe the over agressive manœuvre sometimes with high energy and high HAC angle.
I got back a joystick , I will check that manually.


On that video at 14 mn (HAC time), do you observe something more aggressive ?

https://www.youtube.com/watch?v=fbTFKBWYGbE
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