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Space Shuttle - Development

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Re: Space Shuttle - Development

Postby legoboyvdlp » Tue Jan 15, 2019 8:38 pm

In the advanced DPS tutorial I think you ommited to mention in at least one case to reload the OPS 0 software before checking the SPEC 6 again. I corrected it where I saw it, it may be elsewhere.
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Re: Space Shuttle - Development

Postby Thorsten » Tue Jan 15, 2019 9:17 pm

I see on your screen that item 17 through 20 where you specify where you want to be relative to the target wasn't fed. Did you make some entry and then after item 28 it disappears ?


I suppose it does work, but the accuracy you can achieve for a single shot transfer isn't all that great, so I didn't even bother to try. I suppose at some point later in the approach you may want to refine the solution and then it'll make more sense.

Basically right now you can enter TIG1 and TIG2, do item 28, burn the solution, do item 29, burn the solution and you'll be 'relatively close' (I would hope you'd see ISS, but there was another bug on my test run today, so it's just based on a guess...)
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Re: Space Shuttle - Development

Postby GinGin » Tue Jan 15, 2019 9:47 pm

Alright :)

So either we set Delta T and T2 will be equal to T1 plus Delta T or we put already a T2 without Delta T.
So if we let D X Y and Z to zero, algorithm will try to calculate a Null relative position at T2 with the target, depending on how good is our position and interception trend at T1.


The first on board targeted burn was relatively close in real, 60 km away from the target ( 200 kfeet ish). At which distance did you try the first spec 34 burn?
I made a lot of rendez vous test in Orbiter, and indeed Spec 34 was usefull and accurate only close to the target with already a good phasing and a coherent position of the chaser Vs the target. If not, the solution computed was catastrophic :)


Do you think it would be possible to know the delta angle between the chaser and target , to do a proper phasing and know how many degrees we need to catch up per orbit by adjusting the shape of our orbit?


I am really looking forward to test all that in a few days :)
Like said EatDirt, Christmas again
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Re: Space Shuttle - Development

Postby amalahama » Wed Jan 16, 2019 12:11 am

I love Font = 1 option, it makes displays look smart, but the letters look bland and lifeless compared with "the competence", see pictures

Real:

Image


FG:

Image

"Competence" (e.g. Orbiter)

Image

How could I make font looks bolder, is it possible to change Canvas resolution so it matches GPC output? Why lines are missing in the Font = 1 option, but available in font = 0? How can I modify the svg to better tailor the different modes? (specially MEDS displays, which look a bit different from the real ones)
Last edited by amalahama on Wed Jan 16, 2019 7:18 am, edited 1 time in total.
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Re: Space Shuttle - Development

Postby wkitty42 » Wed Jan 16, 2019 4:05 am

your 3rd photo is not showing up... it says "Photo not found" on a kitten background and wants us to click on it...
"You get more air close to the ground," said Angalo. "I read that in a book. You get lots of air low down, and not much when you go up."
"Why not?" said Gurder.
"Dunno. It's frightened of heights, I guess."
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Re: Space Shuttle - Development

Postby Thorsten » Wed Jan 16, 2019 4:54 am

How could I make font looks bolder, is it possible to change Canvas resolution so it matches GPC output? Why lines are missing in the Font = 1 option, but available in font = 0? How can I modify the svg to better tailor the different modes? (specially MEDS displays, which look a bit different from the real ones)


You actually have to get a font editor of your choice and start modifying the font (add the missing pieces like the greek letters for instance) and make it bolder - the SVG or canvas level can't help you, it's just using the font 'as is', and it's based on a rather generic backend and not a custom thing like in orbiter, so we can't really change its operation (I guess the display shader might potentially help with appearance if you modify it...)

Canvas is doing vector graphics, it'll render on any resolution pretty much the same way - I've just created 1024x1024 images of displays for the fixed base simulator, they look no different. With very few exceptions, the placement of text on the display is exactly the original row/column layout as laid out by the DPS dictionary.

"Competence" (e.g. Orbiter)


Sorry, I don't get the 'competence' joke / allusion/ whatever.
Last edited by Thorsten on Wed Jan 16, 2019 7:45 am, edited 2 times in total.
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Re: Space Shuttle - Development

Postby Thorsten » Wed Jan 16, 2019 5:06 am

The first on board targeted burn was relatively close in real, 60 km away from the target ( 200 kfeet ish). At which distance did you try the first spec 34 burn?


About 120 km - it's nowhere near an optimal solution, it requires about equal prograde and radial components.

So either we set Delta T and T2 will be equal to T1 plus Delta T or we put already a T2 without Delta T.


You can't enter a delta yet.

Do you think it would be possible to know the delta angle between the chaser and target , to do a proper phasing and know how many degrees we need to catch up per orbit by adjusting the shape of our orbit?


The rendezvous planning dialog displays the along-track angle (alpha) and the current approach rate per minute (alpha rate).
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Re: Space Shuttle - Development

Postby amalahama » Wed Jan 16, 2019 4:39 pm

You actually have to get a font editor of your choice and start modifying the font (add the missing pieces like the greek letters for instance) and make it bolder - the SVG or canvas level can't help you, it's just using the font 'as is'


That's a pain, specially make it bolder, and it would still be shown unrealistically crisp. I expect canvas to render the vector graphics into a bitmap to apply to texture. Wouldn't be possible to control this low-level process and render the vector graphics into lower resolutions? Not only would it make fonts and symbols more present, but also you would save some VRAM in the process. In Orbiter (yes, I know you hate comparisons with Orbiter, that's why I tried to avoid using the name!) that's how they control the image in the MEDS, and results are quite good in my opinion (compared with the real thing)
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Re: Space Shuttle - Development

Postby Thorsten » Wed Jan 16, 2019 5:44 pm

That's a pain, specially make it bolder, and it would still be shown unrealistically crisp. I expect canvas to render the vector graphics into a bitmap to apply to texture. Wouldn't be possible to control this low-level process and render the vector graphics into lower resolutions?


I think currently it's rendered into a 512x512 texture - I kind of doubt the real thing has a lower screen resolution... (and in extension I doubt that this is the problem).

that's how they control the image in the MEDS, and results are quite good in my opinion (compared with the real thing


Well, we might just note that we (substantially) differ on the notion of realism here... In my view the orbiter screenshot doesn't resemble a real display at all (colors are far too crisp and homogeneous, no such thing as dirt, shadow or reflection of anything,...)

Anyway, take it up with the developers of the Shiva backend - that's how the font comes out when passed through a standard framework. If you want the font to appear bold, you need to change it and make it bolder. I guess the SSU font is developed for their particular rendering strategy - other fonts seem to do just fine with Shiva.

(Frankly, I'm up to my ears in rendezvous math, I've re-discovered the fact that curvilinear coordinate systems *really* need non-local derivatives today, and I confess that this or that font is a matter of supreme indifference to me at this point...)
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Re: Space Shuttle - Development

Postby GinGin » Wed Jan 16, 2019 6:24 pm

@Amalahama: For the MFD to rend better, you have also to use shaders and effects, it's day and night with ur screen

Image


curvilinear coordinate systems


Wow :shock:
Is it for Clohessy-Whiltshire Equation?
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Re: Space Shuttle - Development

Postby eatdirt » Wed Jan 16, 2019 9:38 pm

When roll is way off, you're likely suffering from integrator windup of some sort (?) What was the control mode (shown in the upper left of the FG-native HUD overlay that you get by pressing 'h') - did that properly switch to an orbital DAP?


First of all, let me mention that I am a complete moron, the instability I discussed in another thread at Mach31 and displayed in the timelapse is just the consequence of me passing to OPS 304 and *not* switching the DAP on AUTO mode!!!! What is fantastic is that, even making that mistake, the pitch is still working in AUTO mode, but the roll seems to be something random :) So, doing things properly, I am happy to tell you Thorsten that your DAP is working perfectly fine even at Mach 31 :mrgreen:

Now, the roll disappearing is real. I, tested, what you say. In OPS 304 I am in aerojet mode, after the bounce, switching to OPS 301, it goes back to RCS ROT DAP-A, but without roll anymore.

I have made other tests, I can switch back and forth from OPS 304 to OPS 301, APU on or off, seconds before reentry, everything works fine, roll control changes mode finely and works all the time in all modes. The roll is lost just after this message appears (in OPS 304)

"Roll control switch to aero"

This message appears only when the pressure built up, I guess the elevons start to be efficient to control roll. From that on, even staying in OPS 304 and putting roll to CSS, the RCS roll thrusters do not fire anymore. Switching to OPS 301, the roll RCS remains off. So I don't think it is due to errors building up, I think that peculiar transition to that "Roll control switch to aero" creates a one way condition from which roll RCS thrusters never go back. I am happy to have a look to the code, but please indicate me in which file I should start digging!

Cheers,
Chris.

PS: unrelated question, Thorsten, do you know how normalmap for earthview should be normalized? I am updating Chris' script to generate clouds and textures to add also the generation of normalmaps. That works, but I don't understand how I should normalize my input elevation map to get a normalmap representing real altitudes in Earthview (maybe my sentence makes no sense as I am not yet fully understanding what I am doing...)
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Re: Space Shuttle - Development

Postby GinGin » Wed Jan 16, 2019 10:06 pm

@Eatdirt: Conercning the roll stuff, it is normal.
During entry , when dynamical pressure is around 10 lb/ft, roll control is switch from RCS to elevons only and Roll rcs are deactivated

Image
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Re: Space Shuttle - Development

Postby Thorsten » Wed Jan 16, 2019 10:11 pm

This message appears only when the pressure built up, I guess the elevons start to be efficient to control roll. From that on, even staying in OPS 304 and putting roll to CSS, the RCS roll thrusters do not fire anymore. Switching to OPS 301, the roll RCS remains off.


Ah - makes sense. I didn't think of that one (I'm surprised you remain in pitch control...)

Code: Select all
setprop("/fdm/jsbsim/systems/fcs/rcs-roll-mode", 1);
setprop("/fdm/jsbsim/systems/fcs/rcs-pitch-mode", 1);


should restore full control if that was the issue.
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Re: Space Shuttle - Development

Postby eatdirt » Wed Jan 16, 2019 10:15 pm

@Gingin, yep, thanks for the figure, nice! I agree with this, but for my quite not standard bounces, that would be nice if the roll aero mode could be reset once switching back to OPS 301 :mrgreen:

@Thorsten, great, thanks, I'll test!!!

By the way,
I think that in game Checklist are sufficient, showing the vital actions to be done to succeed a Shuttle mission without overwhelming the player with advanced stuff that are not vitals and that can be a game breaker


I completely agree with you, but I was more thinking to this:
Image

By default the checklist is in the group "standard", which would remain as it is. I was rather thinking to make another group "Advanced" or "Realistic" with just a list the additional things to do, simply as a quick cheat list of your nice advanced tutorials?
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Re: Space Shuttle - Development

Postby eatdirt » Thu Jan 17, 2019 7:51 am

Code: Select all
setprop("/fdm/jsbsim/systems/fcs/rcs-roll-mode", 1);


Fantastic, that was that. The variable was indeed set to 0 after the bounce and back to OPS 301. On the other hand, the rcs-pitch-mode was aready set to 1, which matches the fact that I was able to use pitch but not roll after bouncing.

Thanks!!!
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