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[PART, 1.0.2] Anatid Robotics / MuMech - MechJeb - Autopilot - Historical thread


r4m0n

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*gets the sarcasm detector*

ANALYSIS INCONCLUSIVE

*go the movies*

Lol sarb XD

Really though, would adapting to the new aero be simply a matter of plugging in the new numbers? And then checking if things work obviously.

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Exp started 2 weeks ago. Since then I spent all my evening and half of my weekends "plugging in the new numbers". The landing sim partially worked for the first time yesterday and there are plenty of other broken stuff.

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The current (old) stock aero was easy when it came to predicting drag as orientation just didn't matter and it was just based on mass of your ship. Now it does (will), so quite a bit harder to predict.

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So this inability to successfully execute maneuver nodes with MechJeb is really starting to frustrate me. I've reduced the node tolerance down to 0.7m/s which is better, but still permits the vehicles to turn in pursuit of the maneuver node before shutting off. In order to prevent any wild chasing of the maneuver nodes, I have to reduce the tolerance down to 2-3 m/s. While both settings are better than the alternative of MJ simply burning endlessly until it's either out of fuel or crashed, this doesn't explain any sort of why this is happening. Something has changed in the last couple of days and I've been unable to determine what it is and how to fix it correctly. I know for a fact that something has changed because vehicles which used to perform just fine with a tolerance of 0.1 must now have their tolerances reduced to the previously mentioned 0.7 or even higher. In response to what Sarbian said about larger ships needing a less restrictive tolerance, I have the following two pictures:

TFRZfZg.png

6JO0KaD.png

As you can see, neither of these is what I could consider a large ship, clocking in at under 10t, and yet both need relatively low tolerances for dV (the latter has been to the mun 4 times with a tolerance of 0.1m/s and yet now it wasn't even working correctly with the 0.5m/s of tolerance seen in that picture) despite their small sizes. I should also mention that in both cases, attempts to achieve specific orbits were often as much as 2-5 km off where in the past MJ had been able to produce nearly perfect orbits.

I don't think that MechJeb is to blame here, as I've completely uninstalled / reinstalled the addon several times, and have tested it alone on a stock installation and it's worked just fine. That being said, I'm at a complete and total loss as to what else might be affecting it's ability to properly execute maneuver nodes. Here is a list of my installed mods:


000_Toolbar
000_USITools
AIES_Aerospace
AJE
AnimatedDecouplers
ArcanumIndustries
ART
ASET
B9_Aerospace
BackgroundProcessing-0.4.0.1.dll
blackheart
Chatterer
CIT
CMES
CoherentContracts
CommunityResourcePack
CommunityTechTree
ConnectedLivingSpace
Contract_science_modifier
ContractConfigurator
ContractPacks
ContractsWindow
CrossFeedEnabler
CrowdSourcedScience
CustomAsteroids
DDSLoader
DeadlyReentry
Diazo
DistantObject
DMagicOrbitalScience
EditorExtensions
EngineIgnitor
EnhancedNavBall
ExtraplanetaryLaunchpads
FalconTech
FASA
FerramAerospaceResearch
FieldExperience
FinalFrontier.dat
Firespitter
FreedomTex
FS_License.txt.txt
ftmn_new
Fusebox
GCMonitor
JSI
KAS
KerbalConstructionTime
KerbalJointReinforcement
KerbalStats
KerbalStockLauncherOverhaul
KineTechAnimation
KittopiaSpace
Klockheed_Martian_Gimbal
Kopernicus
KOSMOS
KSPAPIExt
KSP-AVC
KWRocketry
license.txt
LICENSE_DDSLoader.txt
LICENSE_KittopiaTech.txt
LICENSE_Kopernicus.txt
LICENSE_KopernicusTech.txt
LICENSE_ModuleManager.txt
LICENSE_OuterPlanetsMod.txt
MagicSmokeIndustries
MechJeb2
MechJebAndEngineerForAll.cfg
MM_License.txt
modlist.txt
ModuleManager.2.5.1.dll
ModuleManager.2.5.13.dll
ModuleManager.2.5.8.dll
ModuleManager.2.5.9.dll
ModuleManager.ConfigCache
ModuleManager.ConfigSHA
ModuleRCSFX
MunarSurfaceExperimentPackage
MyMods
NASAmission
NavyFish
NearFutureConstruction
NearFutureElectrical
NearFutureProps
NearFuturePropulsion
NearFutureSolar
Nereid
NovaPunch2
OpenResourceSystem
OPM
OPT
ORSResourcePack
OuterPlanetsMod.version
PlanetShine
PreciseNode
ProceduralFairings
ProceduralParts
RCSBuildAid
RealChute
RealFuels
Regolith
RemoteTech
ResGen
RLA_Stockalike
Sane Strategies
SCANsat
ScienceAlert
SDHI
SETI
SETIgreenhouse
ShipManifest
spacetux
Squad
StageRecovery
StationScience
StockBugFixModules
TechManager
TextureReplacer
ThrottleControlledAvionics
ThunderAerospace
ToadicusTools
toolbar-settings.dat
Trajectories
TriggerTech
TweakableEverything
TweakScale
UmbraSpaceIndustries
UniversalStorage
VenStockRevamp
Virgin Kalactic
VNG
WaypointManager
WildBlueIndustries
WombatConversions
Yarbrough08
000_FilterExtensions

I know it's a long list, but I'm really hoping someone here might know if anything in there could have a negative effect on the way MJ handles manuevers. Again, I know for a fact that this is something that has changed recently, though as far as I can remember, the only recent variable changes to the mix were some edits to MJ's attitude adjustment page. That said, if I can't find the culprit, I'm going to have to start again from fresh installation of the game and start working back to where I am now. I feel like it's going to be a headache, but considering all of the different mods I like to run, I'm probably going to have to start obsessively keeping a changelog for my installs so that when something like this crops up, I can identify quickly all of the recent changes that could have caused it.

On that note, I'm really hoping someone can help me out here as I'd really hate to lose weeks of game progress because I can't track down the source of this issue.

Thanks.

PS: Before someone tells me to just accept the lower tolerances, I don't actually think that is an option. I rely heavily on MechJeb because the bulk of the fun in KSP for me is in designing the vehicles rather than hand flying them everywhere. At these reduced tolerances I can only imagine the difficulties in trying to match orbits with an asteroid or other celestial body, especially when I've got a limited number of engine ignitions thanks to the Engine Ignitor mod. As I see it, I must find a way to correct for this issue or I'll be forced to start over from scratch in the hopes that I'll be able to track the variables well enough to revert it back to working the next time it occurs.

PPS: @Sarbian, I know you're pretty busy with getting MJ ready for v1.0, but as a request for some future release, I'm wondering if you might include some sort of break on the number of times MJ ignites / kills the engine. While using engine ignitor, you have a limited number of ignitions, but MJ doesn't make any accounting for this, sometimes rapid firing the engine 10-15 times in a row while on a descent trajectory and leaving you without an engine at a point in the flight where that will guarantee you're going to become a crater. Again, this is just a thought for some future release, but I'm sure I'm not the only person who uses MJ who might want something like this to exist. Thanks.

Edited by SpacedInvader
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I just set it to 0.1, which is the lowest tolerance I believe. Actually, I think that's the default and lowest tolerance.

I consider 0.1 to be the highest tolerance because it is the most restrictive. Anything less restrictive (0.7 or 3 from my examples above) is a lower tolerance because it's easier to achieve. If I set the tolerance right now to 0.1 m/s, the maneuver node will start to move up towards "Radial +" at about 2-3 m/s left on the node, and then will never get lower than 0.2 m/s, leaving MJ to burn fuel radially until there is no fuel left to burn.

EDIT: I just put together a little imgur album to show exactly what happens when I try to use 0.1m/s tolerance currently:

Javascript is disabled. View full album

As you can see, everything is fine until MJ gets to the end of the burn, at which time the node slides up and pegs itself on Radial+ with 0.2m/s left on the node. MJ will continue to burn like this until there is no more fuel left. This behavior is the same across all of the craft that I've tried to use since this problem has cropped up.

Edited by SpacedInvader
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So it appears that I've solved my own problem and also understand why it might be so obscure. I use Kerbal Construction Time, which includes a simulation mode so you can test your vehicles without having to wait on them to be built. This mode contains something similar to hyperedit (or hyperedit itself) to allow you to jump straight to another planet to test your vehicle there, which is what I was doing to test my Munar lander. Apparently, MJ doesn't like this sort of jumping around, and as a result jumping to the Mun to test resulted in the autopilot acting a little kooky.

After giving up temporarily on solving the issue and wanting to get back to the game, I decided to just fly the mission to see how it turned out and everything went just fine, autopilot included. After the fact, I went back and attempted to simply hyperedit the vehicle up the the Mun to see if that had the same effect as the simulation mode, leading to the behavior described above. As I'm guessing many people don't do much maneuvering after using hyperedit (putting stations in orbit is the most common use that I know of), this control issue probably hasn't surfaced many times in the past. Though I feel that MJ probably is responsible to some degree, I would think that this is an issue that isn't worth the effort of fixing as the situations where it would crop up are highly limited and in most cases wouldn't be critical to anyone's missions.

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oh, yes. It is something I know of. You have to quick save/load for MJ to be properly initialized when moving SoI like that. I'll have to find the root cause one day because it could hide bugs that would only show when players do a single session without saving or quitting the flight scene. But low priority indeed.

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The current (old) stock aero was easy when it came to predicting drag as orientation just didn't matter and it was just based on mass of your ship. Now it does (will), so quite a bit harder to predict.

No, it really wasn't. I know people like to say that but the issue with pre 1.0 stock aero was that it applied drag as an acceleration instead of a force. (i.e, if calculated drag = x then x was applied as x m/s instead of x newtons of drag)

In a way, you could say it ignored mass. (which if you're applying force, you can't do)

@Sarbian: Re maneuver node chasing. I have an idea to eliminate node chasing. At the time that MJ first starts execution, have it hold position instead of actually locking onto the node. You can try that yourself manually either with stock SAS or MJ so that basically you're just ignoring that the node other using it for initial orientation. Really there's no need to change orientation regardless of whether the node stays put (which it won't. It's going to dance when it gets to the end of the burn)

Edited by Starwaster
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I'm totally lost with that NYC comment.

Then again, what else is new when I'm in the picture.

Either way, node chasing has always bothered me. I tend to hover my mouse over the "cancel maneuver" button when letting mechjeb do my burns so I can reduce the need for the craft to suddenly pull away and then have to reorient to deal with a miniscule overshot or something when the necessity of accuracy isn't so necessary such as when aligning for an escape burn or returning from a moon.

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I had an issue in 0.25 and 0.90 with Mechjeb not working in a KSP fresh install (I am on Windows 8.1). The part showed up and could be put on a rocket but the button did not show up. Changing the permissions of the KSP folder so that it did not ask for confirmation when adding/deleting stuff solved the problem.

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I had an issue in 0.25 and 0.90 with Mechjeb not working in a KSP fresh install (I am on Windows 8.1). The part showed up and could be put on a rocket but the button did not show up. Changing the permissions of the KSP folder so that it did not ask for confirmation when adding/deleting stuff solved the problem.

Where is KSP installed? If it's in ProgramFiles (or ProgramFiles (x86)) then move it to a different folder. I installed mine to \Games which I created for that purpose. (ProgramFiles can cause perms issues)

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Hello,

Wow - need I say more I was just gonna say...I applaud and kudos all around and can wait patiently for Mechjeb to updated to 1.0...In career mode it will actually take me a good week or more to even get to Precision Engineering to get the part. Good Luck with Mechjeb update and thank you !!

Cmdr Zeta

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