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[1.0.5] GravityTurn version 1.3.1 - Automated Efficient Launches (1.1 pre-release available)


Overengineer1

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41 minutes ago, Deimos Rast said:

This mod is programmed to basically putter along till 70km, at which point it thinks it's now in space (which in 64x it may not be) and proceeds to tell MJ to circularize.

If using Sigma Dimensions, it actually catches on to the atmosphere boundary. It aims for a minimal height above the edge, but because of the aforementioned slow/not-so-slow un-re-entry into space, it should be advised to use a high altitude for a target as well as a high start time (60-90 sec --> 40) and a shallow initial angle.

I've had trouble with very low TWR first stages, though. It doesn't quite catch onto the time to ap. changing, and gets lost in the weeds.

But, it does work, with a bit of gentle nudging!

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15 hours ago, Deimos Rast said:

Well if you read my posts a few up I talk about playing with it with FAR and DRE. To save you reading: aerodynamically, it flies fine with FAR. The issue is with Deadly Reentry (which I realize is outside the realm of your question), but because your turn is so gradual, the continual friction from the air ends up cooking your capsule, or at the very least burning off your solar panels.

I have heard of it having (or that it at one point had) an issue with the 64x kerbol expansion mod, since that mod moves where the boundary of space is as I understand it. This mod is programmed to basically putter along till 70km, at which point it thinks it's now in space (which in 64x it may not be) and proceeds to tell MJ to circularize. I don't know if that applies to RSS (if that mod changes the scale of the solar system, then it may). This issue may have been entirely fixed though, since it was brought up a while ago.

Well, RSS is really Real Solar System, so yes, it changes the atmosphere.
Another thing- most engines in Realism Overhaul only have one ignition and are non-throttle-able. Does this program play with throttle? I know that Mechjeb has problems with RO because of that.
Also, can you change where you want the Apoapsis to be? Say, at 180km? 

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@Dman979 yes and yes, it uses the throttle a lot to keep you at your target time to  Ap. You can set the final destination height, yes. It seems to have some issues with inclination though sometimes. I'll plug in 90, it goes till 74 then gives up and coninues on like I won't notice or something. Might be a fuel issue, not sure.

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9 hours ago, Deimos Rast said:

It seems to have some issues with inclination though sometimes. I'll plug in 90, it goes till 74 then gives up and coninues on like I won't notice or something. Might be a fuel issue, not sure.

It's not a fuel issue.. GT is unable to correctly achieve polar orbits. The only way to get a polar orbit with GT is to manually fight it using the pitch and yaw controls during the ascent, all the way up until you clear the atmosphere. I think the math/logic GT uses for inclinations other than zero is fundamentally broken in some way.

Edited by JAFO
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Calculating the effects of Coriolis is a little of a challenge. Because you basically have to launch into a slightly different inclination than what you want your final orbit to be. And this inclination depends on not only the final orbit inclination but also on your latitude. I would recommend the author switch to using azimuth as input parameter rather than desired inclination. Or both. You can input one or the other, if you input inclination it automatically does the calculation for azimuth and uses that. Check the orbiter wiki on launch azimuth. Or google images of it. It's fairly easy vector algebra or trigonometry.

I've also noticed that it *CAN* launch fairly accurately into inclined orbits. However I noticed two problems, which came to light when I launched into a 83* inclined orbit:

  • It seems to keep pushing the vehicle to the side of the surface vector node(presumably to improve the final inclination). problem is it does this so much that when the rocket stages it flips out and loses control.
  • At some point, especially when you get out of the thick lower atmosphere(>40km or so) the rocket starts wobbling/oscillating VERY badly. In a 40* range up and down. No idea why. When launching into equatorial its mostly fine. I've only seen the wobbling once or twice.

In addition, it would be nice to have a setting where above a certain altitude/below a certain pressure, the rocket will not only throttle to keep time to AP but pitch as well. This will be very useful for engines that are not throttle-able or when using SRB's.

The tool I found is great for early game as it provides fairly accurate launches and so on, but for late game I stick to MechJeb as it gives me a lot better control over how I launch(espcially with RSS/64K, even considering the problems MechJeb has), albeit less efficient.

Edited by ANWRocketMan
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Here's an initial working version of the DLL for KSP 1.1:  https://github.com/johnfink8/GravityTurn/raw/master/GameData/GravityTurn/Plugins/GravityTurn.dll

This should not be considered a stable version yet, especially since 1.1 isn't even stable.  There's a lot that isn't tested in this version, and quite a few pieces of the code are affected by the new 1.1 API so there might be a few issues.  I'll resume active development now that 1.1 is out, though.  I'll do a formal release when it's ready.

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Great mod, really helps to improve your launch and design skills.  I've been playing this game for 3 years but still learned a lot from this mod.

 

Few suggestions/thoughts

1) Can you write a bit more in the OP about how the best guess system works?  Be handy to have it there rather than having to dig through a 14 page thread.  In particular can you point out where the mod stores best guesses based on ship name? (EDIT GameData\GravityTurn\Plugins\PluginData\GravityTurn\ thanks to JAFO!)

I don't understand how the guess system rates a launch and how it realises if its guess won't get to space or will burn up, ie at what point does it declare a lunch failed? What about if I realise its not getting to orbit and abort will it register not to use those settings?  Sometimes it has got stuck on settings that crash into the sea and I can manually try a steeper launch which succeeds but it insists on giving me the same guess that is only destined for a watery grave and it takes some convincing to get it to make a better guess.

More info in the OP about the guess system and how to help it to make better guesses would be really handy.

Summary of info I'd love to know:-

a) At what point does the mod recognise a successful or failed launch?  Ie Do I have to let it crash for it to realise it should change the guess? 

b) Does pressing abort button mean the mod will not make any decisions about how good the aborted guess was?  Or will the abort suggest to the mod that it should change the guess?

c) Will it learn from my manual settings?  ie If I set turn angle etc manually will it record the efficiency of that launch and use that to improve its own guess?

d) Which settings does the mod optimise via its guesses and which does it ignore?  I've never yet seen it change anything other than "start m/s" and turn angle

 

2) Can we have a way to wipe the database entry of guesses for a particular ship name, so it resets to the default starting guess?

 

3) Can we see a history of all the launch settings the mod is storing for a ship name, ie the ones that it is using to inform its guesses?

Edited by Kerolyov
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3 hours ago, Kerolyov said:

In particular can you point out [where] the mod stores best guesses based on ship name.

Look in GameData\GravityTurn\Plugins\PluginData\GravityTurn\ and you'll find the name-based settings stored for each ship. (yeah, it took me a while to find them, too!)

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  • 3 weeks later...
On 3/30/2016 at 4:51 PM, Overengineer1 said:

Here's an initial working version of the DLL for KSP 1.1:  https://github.com/johnfink8/GravityTurn/raw/master/GameData/GravityTurn/Plugins/GravityTurn.dll

This should not be considered a stable version yet, especially since 1.1 isn't even stable.  There's a lot that isn't tested in this version, and quite a few pieces of the code are affected by the new 1.1 API so there might be a few issues.  I'll resume active development now that 1.1 is out, though.  I'll do a formal release when it's ready.

Looking forward to it OE1. Great mod!

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  • 2 weeks later...
On 2016-04-30 at 5:06 AM, Mat2ch said:

Is it ok now to ask, when we might expect a stable version for 1.1? :)

I've been testing it all day, nearly a hundred launches to create an optimal launch craft using level 3 techs (General Rocketry, Stability and Suitability). Seems functional enough with Overengineer1's 1.1 dll.

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17 hours ago, veryinky said:

I've been testing it all day, nearly a hundred launches to create an optimal launch craft using level 3 techs (General Rocketry, Stability and Suitability). Seems functional enough with Overengineer1's 1.1 dll.

But @Overengineer1said that this version shouldn't be considered as stable. I'm waiting for an official release :)

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4 hours ago, OldLost said:

Sure wish we'd get an official 1.1.2 version posted though. Would love to have this available through CKAN.

I've yet to run into any problems in 1.1.2 with the 1.1 pre release. Only thing I've noticed is that launch at any orbital inclination is a trial and error deal where I've found you basically need to add 15 degrees to whatever inclination you want to achieve. I believe it's been that way for a while but I couldn't really you for sure 

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2 hours ago, mtpatane said:

I've yet to run into any problems in 1.1.2 with the 1.1 pre release. Only thing I've noticed is that launch at any orbital inclination is a trial and error deal where I've found you basically need to add 15 degrees to whatever inclination you want to achieve. I believe it's been that way for a while but I couldn't really you for sure 

I think that's just because it's not particularly good at accounting for Kerbin's rotational speed (if it does at all).

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Does anybody knows how to use this with Real Solar System? I'm using SMURFF (which don't limit ignitions or throttle) but I can't get it to recognize that it is RSS and even putting 250 km of destination height I can't get "best settings" to work properly because of "time to AP". I don't know how much time I need to put on this, because now the mod thinks 40 seconds is enough but clearly isn't. This mod is supposed to work with RSS?

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Love this mod! Thanks a lot!

I am using it with 1.1.2 quite successfully.

Has anyone noticed in 1.1.2 that the AP hold time sweet spot seems to be around 50-55 seconds and for sensitivity it seems to be around 0.3 or 0.35?

After I figure out a turn angle and start speed, this shaves off more dV. Tried with the KerbalX and my own craft.

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