MechJeb 2 - Patch test bed release (October 10)

[sarbian]

Maybe this has been discussed elsewhere (I just found this thread today), but is there a specific reason to remove CommandModule? I kinda liked tacking MechJebs on to intermediary stages so I could deorbit them.

There's afaik no other surface-attachable CommandModule (so that's 2 more parts for a cubic strut and a probe) and certainly none as lightweight.

With 0.21.1 KSP changed the way it choose the controlpod in command of the ship ( control from here ) and most of the time it choose the MJ2 module. Since most player don't place their MJ2 module pointing upward there was a lot of report of MJ2 trying to fly the ship into the ground.

Removing the controlmmodule in the MJ2 part helped to get less "false" bug report. As other said you can edit the part to add it back, or you can create a copy of the cfg and create your own attachable control pod.

I'm not really sure it would increase performance any, but I do think it would be a cleaner approach overall to extend Monobehavior rather than Partmodule since this isn't really a part level mod. I'm assuming right now the code is simply using part and part.vessel, but you can just as easily access the current vessel and control part using FlightGlobals.ActiveVessel and something like foreach (Part p in FlightGlobals.ActiveVessel.parts) if (p.isControlSource) controlPart = p; to set those up. Most of the stuff MechJeb deals with is outside part/partmodule anyways, so I don't think it would be all that huge of a coding change to make it partless.

Not sure it would increase perf at all. Only 1 MJ2 is active on a vessel even if there is more thant one on it ( at least it should ) so it won't change perf. And I'm sure some would complain that MJ2 is always on

Sarbian had to make changes to both ModuleManager.dll and MMSarbianExt.dll before it all worked properly. And I seem to recall him mentioning that he was leaving for vacation so I'm guessing he didn't have time to update the front page re: the bug fixes

Yes, I had to do that to fix the bug reported bu Majiir for Partless addons.

Hopefully ialdabaoth will be back soon and he can do an official fix for his version.

And I am still here until mid next week, but a bit busy while I get ready for my 1 month trip.

Edited September 5, 2013 by sarbian

[Potterus]

Just posted this in the original MJ thread, maybe one of you fine chaps has found a solution for this already.

Having an issue with Mechjeb 2.0.9 landing guidance when trying to land on Duna. This only seems to apply to Duna, works fine on the Mun, Minmus and Eeloo (other places I've been too with this mod so far).

If I choose "Land at Target", and I've tried this at different places, then Mechjeb sets up a seriously odd eccentric orbit (over 900km at one point) before correcting it and doing a near vertical descent to the landing coordinates. So it makes it there, right on the bulls-eye, but spends a huge amount of fuel doing so.

Tonight I tried an experiment where I flew a craft that was basically a fuel tank, engine, probe and power systems to see what the difference would be between landing at a target I chose and using the "Land Somewhere" option which seems to work fine.

Both times were from a 100km equatorial orbit. For "Land at Target" I chose the deep valley near the equator.

Land at Target - expended 2820 m/s

Land Somewhere - expended 1162 m/s

After the "Land Somewhere" option I used Ascent Guidance to put the probe back into a 100km orbit, which used 1473 m/s. So if I'm not fussed about where I land, I can put a craft on Duna and back into orbit for a total of 2635 m/s which is a saving of 185 m/s over just landing on Duna at a site of my choosing.

Anyone else encountered this and know if there is a fix? Maybe a different start altitude or orbital setup?

[Geschosskopf]

Anyone else encountered this and know if there is a fix? Maybe a different start altitude or orbital setup?

I agree that stock MJ's "land at a target" thing is a bit wonky when the planet has an atmosphere. Often, it does a de-orbit burn that looks spot on and the info box says it's within about 200m. But then for no apparent reason the ship switches ends and starts burning prograde until the orbit no longer touches the ground and keeps getting higher and higher, pointlessly wasting gobs of fuel. This doesn't happen on airless planets, just those with atmospheres.

However, this seems to happen only when you tell MJ to land at a spot that's too close ahead of where your ship currently is. MJ appears to need somewhere between 1/3 to 1/2 an orbit. So, the best way to avoid or at least minimize this behavior is to start the process with as much of an orbit to go as possible, like right after you've passed over the target so you get it the next time around. USUALLY this will prevent the spurious "wrong way" burning. However, what often happens instead is that the rocket will now burn at idle speed pretty much all the way down, saying it's doing a coarse correction of like 0.1m/s, but this number never changes and the landing error never decreases, so it's just a pointless waste of fuel again.

So all in all, I have the best luck with not only engaging the landing autopilot a full orbit in advance, but also then disengaging the autopilot immediately after the de-orbit/plane-change burn when the error is about 200m. Then I fly it myself the rest of the way down, including opening any parachutes (which MJ doesn't do very well, either). Once the chutes are open, I tell it to "land somewhere" and it goes down just fine from there.

[AncientGammoner]

I've flown a couple missions with the old dll and then this dll and honestly the only differences I noticed were actually regressive. The new dll turns towards nodes much less smoothly (almost whips around sometimes) and I've seen it struggle to get to really simple node locations (fly right past them and then barely come back). And is there a reason why it sometimes spins on the long axis when turning toward a node, because that makes no sense. Also I've seen the new dll warp right past nodes on multiple occasions (come out of warp at like +4 minutes for a simple 5 second burn). It's the same with the old version, but is MechJeb ever going to stop oscillating the whole ship, especially large vehicles with gimbaled engines. I mean mechjeb will rip apart some vehicles when they're going straight up just by oscillating it to death, yet you can turn mechjeb off then ignite them and not even touch the controls and they fly straight as an arrow.

[egreSS]

In the zip file, the AR202 part.cfg is time stamped 9/1/2013 12:02pm, and the MechJeb2.dll is time stamped 8/31/213 3:28pm.

On edit: Not sure why line breaks and vBulletin shortcodes are being filtered out of my reply. *sigh*

Thanks for the reply, I was going off the fs modification date.

BTW - The reason the linebreaks get messed up is because vBulletin try's to preserve formatting when pasting from clipboard and it does a piss poor job. I instead use Ctrl-Alt-V or if you use chrome: R Click > Paste as plain text. I believe you can disable it somewhere too.

Not that it's needed now but - Any chance anyone actually has the build instructions for Unity modules? ksp specific if possible? I don't know why but I want to play around with building a module from source.

[sarbian]

@AncientGammoner

Do you use other mods ? Since the larger part of the patch does improve turning and lower oscillation I find it strange that you have this problem. Can you post a ship file ?

For the warp thing you most likely have it with the default MJ since nothing related to warp is changed afaik.

@56egreSS With Visual Studio or Unity Monodevellop ? I use VS but it should be the same for both. Copy the source somewhere, add the project files and open the .sln

Here is my project files. You'll need to change the "C:\Games\ksp-win-0-21-1" path from them. hack away and share your improvement

MechJeb2.csproj :

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    <Compile Include="alglib\alglibmisc.cs" />
    <Compile Include="alglib\ap.cs" />
    <Compile Include="alglib\diffequations.cs" />
    <Compile Include="alglib\linalg.cs" />
    <Compile Include="alglib\optimization.cs" />
    <Compile Include="CelestialBodyExtensions.cs" />
    <Compile Include="ComputerModule.cs" />
    <Compile Include="DisplayModule.cs" />
    <Compile Include="FuelFlowSimulation.cs" />
    <Compile Include="GLUtils.cs" />
    <Compile Include="GuiUtils.cs" />
    <Compile Include="LambertSolver.cs" />
    <Compile Include="MathExtensions.cs" />
    <Compile Include="MechJebAR202.cs" />
    <Compile Include="MechJebCore.cs" />
    <Compile Include="MechJebModuleAscentAutopilot.cs" />
    <Compile Include="MechJebModuleAscentGuidance.cs" />
    <Compile Include="MechJebModuleAscentPathEditor.cs" />
    <Compile Include="MechJebModuleAttitudeAdjustment.cs" />
    <Compile Include="MechJebModuleAttitudeController.cs" />
    <Compile Include="MechJebModuleCustomInfoWindow.cs" />
    <Compile Include="MechJebModuleDockingAutopilot.cs" />
    <Compile Include="MechJebModuleDockingGuidance.cs" />
    <Compile Include="MechJebModuleFlightRecorder.cs" />
    <Compile Include="MechJebModuleInfoItems.cs" />
    <Compile Include="MechJebModuleJoke.cs" />
    <Compile Include="MechJebModuleLandingAutopilot.cs" />
    <Compile Include="MechJebModuleLandingGuidance.cs" />
    <Compile Include="MechJebModuleLandingPredictions.cs" />
    <Compile Include="MechJebModuleManeuverPlanner.cs" />
    <Compile Include="MechJebModuleMenu.cs" />
    <Compile Include="MechJebModuleNodeEditor.cs" />
    <Compile Include="MechJebModuleNodeExecutor.cs" />
    <Compile Include="MechJebModuleRCSBalancer.cs" />
    <Compile Include="MechJebModuleRCSBalancerWindow.cs" />
    <Compile Include="MechJebModuleRCSController.cs" />
    <Compile Include="MechJebModuleRendezvousAutopilot.cs" />
    <Compile Include="MechJebModuleRendezvousAutopilotWindow.cs" />
    <Compile Include="MechJebModuleRendezvousGuidance.cs" />
    <Compile Include="MechJebModuleRoverController.cs" />
    <Compile Include="MechJebModuleRoverWindow.cs" />
    <Compile Include="MechJebModuleSettings.cs" />
    <Compile Include="MechJebModuleSmartASS.cs" />
    <Compile Include="MechJebModuleSpaceplaneAutopilot.cs" />
    <Compile Include="MechJebModuleSpaceplaneGuidance.cs" />
    <Compile Include="MechJebModuleStageStats.cs" />
    <Compile Include="MechJebModuleStagingController.cs" />
    <Compile Include="MechJebModuleTargetController.cs" />
    <Compile Include="MechJebModuleThrustController.cs" />
    <Compile Include="MechJebModuleThrustWindow.cs" />
    <Compile Include="MechJebModuleTranslatron.cs" />
    <Compile Include="MechJebModuleWarpController.cs" />
    <Compile Include="MechJebModuleWarpHelper.cs" />
    <Compile Include="MuUtils.cs" />
    <Compile Include="OrbitalManeuverCalculator.cs" />
    <Compile Include="OrbitExtensions.cs" />
    <Compile Include="PartExtensions.cs" />
    <Compile Include="PIDController.cs" />
    <Compile Include="Properties\AssemblyInfo.cs" />
    <Compile Include="RCSSolver.cs" />
    <Compile Include="ReentrySimulation.cs" />
    <Compile Include="Properties\Resources.Designer.cs" />
    <Compile Include="SpeechBubble.cs" />
    <Compile Include="Vector6.cs" />
    <Compile Include="VesselExtensions.cs" />
    <Compile Include="VesselState.cs" />
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MechJeb2.csproj.user :

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MechJeb2.sln

Microsoft Visual Studio Solution File, Format Version 11.00
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Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "MechJeb2", "MechJeb2.csproj", "{9FC90AE6-C2E4-47F1-A6D1-DB4731A40BE3}"
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		StartupItem = MechJeb2.csproj
	EndGlobalSection
EndGlobal

[sarbian]

I agree that stock MJ's "land at a target" thing is a bit wonky when the planet has an atmosphere. Often, it does a de-orbit burn that looks spot on and the info box says it's within about 200m. But then for no apparent reason the ship switches ends and starts burning prograde until the orbit no longer touches the ground and keeps getting higher and higher, pointlessly wasting gobs of fuel. This doesn't happen on airless planets, just those with atmospheres.

It's a TWR problem. With ship with a low TWR and atmosphere the re entry simulation get negative number and NaN ( division by zero, sqrt of a negative number) falling speed , then it gets mad. I tried to fix this but when I fix the simulation the ship don't land where asked ( it lands way shorter ) or get madder and do a deorbit burn

It's unlikely I'll find a fix for that in the week before I go away.

[AncientGammoner]

Do you use other mods ? Since the larger part of the patch does improve turning and lower oscillation I find it strange that you have this problem. Can you post a ship file ?

Yeah I use too many mods to count (and unfortunately I deleted the ship designs that are unstable so I don't accidentally use them). Nevertheless, I believe the oscillation I was seeing has to do with the flex of the ship. If you build large/tall vehicles (I typically use the 3.75m/5m KW and Novapunch2 engines for my first stages) they have some flex to them, so when mechjeb detects movement one way I'm guessing it assumes the whole ship is going off course when in reality it's just the ship flexing a bit in that direction. It then tries to compensate which causes it to swing back, causing more flex, then oscillations, then (if you don't have enough struts) usually destruction. I've found that enabling KerbCom Avionics "Stock Engine Control" mode will usually dampen those oscillations though.

[DerekL1963]

And is there a reason why it sometimes spins on the long axis when turning toward a node, because that makes no sense.

Yes, spinning on the long axis simplifies the math. I can't speak to MechJeb, but real life rockets do this... When you hear the call "roll program"? Part of that is the booster being spun on it's long axis to align the flight, body, and guidance system planes. (This originated in the analog days, it's not *strictly* needed nowadays though.)

[sojourner]

I've seen some behavior where a ship will decide to take the "long way around" to get to the target on the navball. For example, it might be pointing about 90 degrees from target to start, but instead of just changing by 90 degrees, it will go a full 270 around the axis of change. This hasn't happened during ascent, mostly with the docking autopilot and a couple times with autorendezvous. Anyone got any ideas why?

[viperwolf]

AncientGammoner

I have the same behavior with flex on big/tall, using NP 5m parts. It causing mech jeb to fluctuate during ascent. Ive strutted then to death, and it did not help. i even strengthened the part in cfg, still did not help. No solution so far

[Starwaster]

I've seen some behavior where a ship will decide to take the "long way around" to get to the target on the navball. For example, it might be pointing about 90 degrees from target to start, but instead of just changing by 90 degrees, it will go a full 270 around the axis of change. This hasn't happened during ascent, mostly with the docking autopilot and a couple times with autorendezvous. Anyone got any ideas why?

I blame it on Force Roll. Or at least it seems to me that it's less likely to behave that way when I have it off than when I have it on. How does that mesh with your experiences?

(Force Roll should definitely be the lowest priority when MJ2 is aligning to any node seeing as how it becomes a trivial matter for it to achieve after alignment is complete)

I've flown a couple missions with the old dll and then this dll and honestly the only differences I noticed were actually regressive. The new dll turns towards nodes much less smoothly (almost whips around sometimes) and I've seen it struggle to get to really simple node locations (fly right past them and then barely come back). And is there a reason why it sometimes spins on the long axis when turning toward a node, because that makes no sense. Also I've seen the new dll warp right past nodes on multiple occasions (come out of warp at like +4 minutes for a simple 5 second burn). It's the same with the old version, but is MechJeb ever going to stop oscillating the whole ship, especially large vehicles with gimbaled engines. I mean mechjeb will rip apart some vehicles when they're going straight up just by oscillating it to death, yet you can turn mechjeb off then ignite them and not even touch the controls and they fly straight as an arrow.

Under Attitude Control, try adjusting Tf. For large ponderous ships set it to 1. It will make its maneuvers less aggressively, more gradually.

@Sarbian On the subject of Attitude Control and the Tf setting, those settings really need to be saved per ship as other MJ2 modules are. It's too easy to forget that I need to go and change that setting every time I change vessels.

Edited September 6, 2013 by Starwaster

[RabidMonkey]

Interesting plugin interaction that I'm not sure has been mentioned: When using FAR, the "Limit to terminal velocity" tick doesn't seem to do anything - I had a medium booster with the main engines running full throttle going mach 3 at ~5km before it disintegrated. With FAR not installed, my main engines throttled back and let the boosters do the pushing as I expected. Am I missing something, or is there something different about how FAR calculates terminal velocity that MechJeb doesn't like?

[somnambulist]

Interesting plugin interaction that I'm not sure has been mentioned: When using FAR, the "Limit to terminal velocity" tick doesn't seem to do anything - I had a medium booster with the main engines running full throttle going mach 3 at ~5km before it disintegrated. With FAR not installed, my main engines throttled back and let the boosters do the pushing as I expected. Am I missing something, or is there something different about how FAR calculates terminal velocity that MechJeb doesn't like?

FAR doesn't really tie into MechJeb -- MechJeb is still assuming the stock aerodynamic parameters, not the values substitute by FAR.

[PhilMcgroin]

I've flown a couple missions with the old dll and then this dll and honestly the only differences I noticed were actually regressive. The new dll turns towards nodes much less smoothly (almost whips around sometimes) and I've seen it struggle to get to really simple node locations (fly right past them and then barely come back). And is there a reason why it sometimes spins on the long axis when turning toward a node, because that makes no sense. Also I've seen the new dll warp right past nodes on multiple occasions (come out of warp at like +4 minutes for a simple 5 second burn). It's the same with the old version, but is MechJeb ever going to stop oscillating the whole ship, especially large vehicles with gimbaled engines. I mean mechjeb will rip apart some vehicles when they're going straight up just by oscillating it to death, yet you can turn mechjeb off then ignite them and not even touch the controls and they fly straight as an arrow.

This! Since grabbing this version, I've noticed the same thing. I mean, docking autopilot works like a dream now where it never used to before. Landing autopilot seems to betray you and send you crashing into the ground a bit less. But yea, it seems to hate nodes now. definitely less friendly towards ships that take a little while to manuever. Sometimes it'll just sit there rolling the ship so quickly that its yaw and pitch commands are wasted because 2 seconds later its rolled 180 degrees and gone back to where it started. I have to sit there and manually kill the roll every 4 seconds if I want it to ever point at the node. I haven't played with the tf settings yet, might give that a go. But the force roll feature doesn't seem to help it much. Which is disappointing, since I normally don't even use the full autopilots, I mainly use MJ just for smart a.s.s. to point at things quicker.

[Starwaster]

This! Since grabbing this version, I've noticed the same thing. I mean, docking autopilot works like a dream now where it never used to before. Landing autopilot seems to betray you and send you crashing into the ground a bit less. But yea, it seems to hate nodes now. definitely less friendly towards ships that take a little while to manuever. Sometimes it'll just sit there rolling the ship so quickly that its yaw and pitch commands are wasted because 2 seconds later its rolled 180 degrees and gone back to where it started. I have to sit there and manually kill the roll every 4 seconds if I want it to ever point at the node. I haven't played with the tf settings yet, might give that a go. But the force roll feature doesn't seem to help it much. Which is disappointing, since I normally don't even use the full autopilots, I mainly use MJ just for smart a.s.s. to point at things quicker.

Why should force roll help with that situation? That's not what it's for.

Yes, by all means change the Tf setting. Force Roll affects only roll, not yaw or pitch. The final effect of Force Roll are noticeable after it has finished all maneuvers. It's easiest to spot for the prograde/retrograde & normal orientations. When in orbit around a planet you will notice that with Force Roll set to 0 that the 'top' of the cockpit is oriented away from the planet surface and the floor is pointed at the ground.

It has a different meaning when the docking autopilot's 'Force Roll' is set. When 0 is set it will try to align the top of the port with the other port's 'top'.

[Mihara]

Oh, speaking of force roll, I remembered I wanted to ask for this...

During ascent guidance, on certain kinds of rockets, it would be helpful if I could force a certain roll -- especially if that would only trigger once it's cleared the tower, so, let's say it could kick in after the altitude from the bottom equal to center of mass distance to ground multiplied by two. Is that feasible?

[PhilMcgroin]

Because I was hoping with force roll locked to an angle, it might actually be able to pitch and yaw to the maneuver node coming up, instead of just spinning around and around and pointing in pretty much the same direction for two minutes.

[Starwaster]

Oh, speaking of force roll, I remembered I wanted to ask for this...

During ascent guidance, on certain kinds of rockets, it would be helpful if I could force a certain roll -- especially if that would only trigger once it's cleared the tower, so, let's say it could kick in after the altitude from the bottom equal to center of mass distance to ground multiplied by two. Is that feasible?

Or that could be triggered when a certain stage triggers

[drtedastro]

At a certain time on a certain stage....... It would be nice to be able to stack commands to happen at certain points in the flight.... but any way to control roll during ascent would be great.

[mwlue]

Under Attitude Control, try adjusting Tf. For large ponderous ships set it to 1. It will make its maneuvers less aggressively, more gradually.

hmm, this seems help alot on my 640ton mun rocket. I have cut down half of the gimbal range (.5 - 0.25) of the NP 5x bear engines tho.

[Zeroignite]

At a certain time on a certain stage....... It would be nice to be able to stack commands to happen at certain points in the flight.... but any way to control roll during ascent would be great.

Erm, what's difficult about controlling roll manually?

[Gaius]

At a certain time on a certain stage....... It would be nice to be able to stack commands to happen at certain points in the flight....

Indeed. I often wish MechJeb would jettison my fairings at >69k. Sometimes I'm not really paying attention (or am literally afk), and if I come back with the ship in orbit and the fairings still on, ejecting at that point creates debris that needs cleaning, whereas ejecting on time usually leaves it sub-orbital so it just takes care of itself. Don't know if that requires a full blown stacking commands functionality, perhaps just a checkbox that says "Stage as leaving atmosphere" or something like that. Obviously you'd want to leave it off if your vehicle doesn't have fairings to eject...

A bigger nifty, though, would be to get the delta-V calcs for stages correct. Often my "stage dV" displays as 0 when I clearly have plenty, and the stage before you eject fairings is one that's dV display is always broken... not a BIG deal, but annoying. The bigger deal is rockets that display 0 dV on their last stage or two. Bad enough when you're building the rocket and you can't see what kind of dV the probe at the end will have once it's on that stage, but worse when in-flight it just can't figure out your dV, and there's no apparent reason why it would be confused, there's no more stages to consider or anything, it's just a probe with a fuel tank and an engine.

Straying further off-topic with my gripe list, there's one big one that I'd kill to see fixed before anything else: stop my bloody ships from spinning around and smacking the space station the moment I hit "undock". At one time, I could have sworn, MechJeb's Smart A.S.S. would simply default to "off" for any ship that undocked, but there was a serious regression in behavior some months ago, and now a newly undocked ship, which you're not in control of, will have its onboard MechJeb suddenly engage in violent maneuvers the moment it undocks as it tries to do whatever it thinks it ought to be doing, and there's simply no way to switch to the ship quick enough to stop it from smashing itself against the side of the station sometimes. I notice this doesn't happen if I quicksave and then reload the game before undocking, but if I've been repeatedly docking and undocking during the same session (as I was the other day as I reconfigured an assembled-in-orbit station), undocking a previous docked craft causes its Jeb to run wild. It appears to have its settings something like what they were when it docked, but often they make no sense anymore, like it's trying to align to a target, except you now have a different target than you did when you docked, and it decides it needs to point in a completely different direction RIGHT NOW. Other times I swear it's getting confused about which ship it is -- it'll adopt some Smart A.S.S. setting that I'm pretty sure a completely different ship had that docked previously. In any case, it doesn't help that my station tugs are designed with enough torque to manhandle heavy station components, so when they're undocking with nothing in tow, they can spin around with incredible speed and force. After a few explosions, broken pieces, and craft nearly kicked out of orbit, I just got into the save/reload habit before each undocking, but it's a pain... if I had to pick just one thing to get fixed, it would be that.

Gripes aside, I do love this mod. As complex as it is and as much as it does, obviously it's going to have some rough spots, but overall it's an insanely great piece of work. Gotta love it...

[Mihara]

Erm, what's difficult about controlling roll manually?

Difficult, nothing. There's nothing particularly difficult about doing ascent control manually either, but if I wanted to do it every time, I probably wouldn't need MechJeb.

[HeadHunter67]

Erm, what's difficult about controlling roll manually?

Well, for one, you have to turn off MJ to do that. So what's the point of Ascent Guidance if you have to disable it to do what you want to add to it?

I'm going to surmise that you just didn't think it over before asking. I hope you're not deliberately trolling.