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

[zgrillo2004]

I don't think Nova Punch is at fault here I think it's MJ2, have you tried a clean install of KSP and docking with MJ2?

Sorry for the late reply. I will try that in a vanilla installation

Edit: it seems to be working. I dont know why. the spacecraft that was having the problems has Remotetech and the orbital construction mod on there. I will try to find out more on why its spazzing out.

Edited August 4, 2013 by zgrillo2004

[Starwaster]

Re: the discussion about MechJeb and where the craft is controlled from, that's definitely something that the player should have to decide on a case by case basis as the situation with his craft changes. (that in response to a few remarks about MJ deciding what part the craft is being controlled from; the only really relevant part being whichever one the player chose)

@Sarbian, on the subject of the roll control in autodocking, I had a devil of a time getting two ships docked because they have to be lined up with each other with pretty much no degree of tolerance. (they dock side by side using two docking ports fore and aft). Each ship kept trying to roll several degrees off and I wanted to try using the roll feature but I wasn't sure what to put in there. If it says 0 degrees, what is that in relation to? Does it already try to line up a certain way with the other docking port and you're telling it to orient a different way relative to that port? Or is it relative to something else?

[sojourner]

So you are trying to launch a space plane with MJ?

Nope.

10 characters.

[Diche Bach]

Anyway with Mechjeb or any other addon to auto-deploy my sputnik's parachutes (say when vel < 200 m/s) on the auto-land thingy?

[sojourner]

Had an odd one today. Was playing around with a 2 stage rocket I made just for fun. Second stage gets to orbit no problem and with a ton of fuel left so I decide, well, might as well land at KSC using autoland. I've got plenty of D/v and TWR for it. Everything goes flawlessly. The automated landing is coming in right on target, lowers gear, fires engines and.... decides to hover at roughly 1000 meters until the fuel runs out! Never seen this happen before. While it was hovering I noticed the target on the navball was jumping all over the place, so I suspect the rocket was just too wobbly. I'll try strutting it later and see what happens.

This was using Sarbian's .dll

[drtedastro]

Regarding the Attitude Adjustment for tweaking the PID. What are the variables again? The Wiki Doesn't seem to have the explanations on it for this window.

i dont think it does anything atm. i tried setting the values to extreme numbers and nothing changed

Does anyone know where I can find info regarding the attitude adjustment parameters? This has been banged around for awhile now in the thread, but no 'answer' seems to have come out....

many thanks..

[Rassa Farlander]

Hey, Sojourner, I had something like that happen on Minmus the other day with me and a regular install of mechjeb, it decided to hover and the navball target going crazy, I disengaged the autopilot and then clicked land anywhere since I was already over my target, and that worked.

[Unikraken]

What happened to the old parts? Any way to get them back?

[sarbian]

@Sarbian, on the subject of the roll control in autodocking, I had a devil of a time getting two ships docked because they have to be lined up with each other with pretty much no degree of tolerance. (they dock side by side using two docking ports fore and aft). Each ship kept trying to roll several degrees off and I wanted to try using the roll feature but I wasn't sure what to put in there. If it says 0 degrees, what is that in relation to? Does it already try to line up a certain way with the other docking port and you're telling it to orient a different way relative to that port? Or is it relative to something else?

At 0° it should align the "UP" of your craft with the UP if the docking port you control from with the UP of the docking port you dock to. It's nice for those with alignement OCD, like me

But your screenshot show that I messed up the UI in one of my update.

I asked R4mon if I can do a different thread for my build. I don't want to mix bug report from my version with his.

Edit : sig

Edited August 5, 2013 by sarbian

[Toyotawolf]

At 0° it should align the "UP" of your craft with the UP if the docking port you control from with the UP of the docking port you dock to. It's nice for those with alignement OCD, like me

But your screenshot show that I messed up the UI in one of my update.

I asked R4mon if I can do a different thread for my build. I don't want to mix bug report from my version with his.

That will be cool

[rkman]

mechjeb 2.09 regularly overshoots maneuver nodes, especially on interplanetary trajectories.

[DChurchill]

I've noticed something with .21 regarding docking. It has a bad tendency of changing the control focus and then realigning the combined craft after docking. Pretty traumatic if you have a big station chock full of inertia. AT least that's what the problem seems to be.

I don't remember this from .20.

Also, Sarbian, do you have another build that's not the "official" 2.0.9? Just wondering where the download link is. Also, hope you and Ramon work something out regarding who's version is the "real" one. Not implying that there's any sort of conflict, just that two different MechJebs would be bad, IMHO.

[sarbian]

R4m0n's is the real one. It's his mod. I just integrate some submited patch and do quick fix, nothing fancy.

I added the link in my sig for now.

You can also use the .cfg with no command pod fo those who don't want to "control from here" all the time : https://raw.github.com/sarbian/MechJeb2/Raf04_Sarbian/Parts/MechJeb2_AR202/part.cfg

Edited August 5, 2013 by sarbian

[Valley]

I would like to apologize to MechJeb 2. I thought it had issues docking but a recent docking showed that the problems were with my own logic. When approaching a station or ship I had normally had MechJeb 2 stop at 40 to 50 meters away than started up the docking autopilot. The refueling rocket or delivery rocket always seemed to freak out at that point. Now I know why. It was freaking out.

You see, yesterday I designed a drone to work on my weapons platform. You know, probe with monopropellant (which is a word no matter what the computer says), RCS units, a Jr Docking port AND a normal size. Move warheads about, rearm ships, maybe act as a tug for smaller ones. I sent it up and had it close in but allowed it to stop at the default distance of 100 meters. Than I turned on the docking autopilot.

It hardly seemed to do anything. I didn't even see the plumes that it normally produced when docking. It seemed to be doing nothing at all. Yet...I checked the resources which showed it was using monopropellant (which is spelled correctly you stupid computer) but in very small amounts. Tiny amounts. And I realized, in a flash of insight, which only happens to me once in a few weeks, that it was all my fault.

MechJeb 2 had to line up with the docking port. Starting at 100 meters gives it more time to adjust and maneuver. Starting at 40 to 50 it had no time at all and even had to back off or hold position. It starts to rock, twist and turn as it tries to do in 50 meters what it was designed to do in 100 meters.

It was totally due to my idea that I was saving time and fuel by getting it closer that it was freaking out. But I was wrong in both counts and blamed the mod. Poor little thing.

I am wrong. I am sorry.

[Montieth]

You could abort the landing sequqence or once the gear is down hit g and bring them back up....nut to what point? Crash?

Some landers are carrying a package that needs to touch down first before you touch down the lander. Say in the form of a sky crane.

[Tassyr]

Hey, Sojourner, I had something like that happen on Minmus the other day with me and a regular install of mechjeb, it decided to hover and the navball target going crazy, I disengaged the autopilot and then clicked land anywhere since I was already over my target, and that worked.

Another way I've found to combat this is to set the default descent speed from 0.5 to 2.5. You'll have to change this _EVERY_ time though.

[Fett2oo5]

I'll load a stock rocket, say the Z-Map, I can launch it manually. If I try to use MechJeb Ascent Guidance I'll set all the parameters I'd like then launch. Engines ignite, supports fall away, but the craft stays put. After a while I noticed that the "main component" (the cockpit, command pod or Probodobodyne module) stays in the exact same X,Y,Z location. Even after all the components have functioned and fallen to the ground.

Because this "main component" (I don't know what to call it) stays locked in it's 3D location the engines just push against it and nothing moves skyward.

Am I don't something wrong?

Am I not doing something important?

Please help.

[EDIT] Nevermind, I figured out what was wrong.

Edited August 5, 2013 by Fett2oo5

[Starwaster]

Had an odd one today. Was playing around with a 2 stage rocket I made just for fun. Second stage gets to orbit no problem and with a ton of fuel left so I decide, well, might as well land at KSC using autoland. I've got plenty of D/v and TWR for it. Everything goes flawlessly. The automated landing is coming in right on target, lowers gear, fires engines and.... decides to hover at roughly 1000 meters until the fuel runs out! Never seen this happen before. While it was hovering I noticed the target on the navball was jumping all over the place, so I suspect the rocket was just too wobbly. I'll try strutting it later and see what happens.

This was using Sarbian's .dll

I had it put me on an escape trajectory out into the Kerbol system proper.... thankfully I usually F5 before doing things like autolanding

[sojourner]

It was totally due to my idea that I was saving time and fuel by getting it closer that it was freaking out. But I was wrong in both counts and blamed the mod. Poor little thing.

I am wrong. I am sorry.

The difference isn't how close you started from. It's the craft you are using. Try that same craft from 50 meters.

[Starwaster]

Another way I've found to combat this is to set the default descent speed from 0.5 to 2.5. You'll have to change this _EVERY_ time though.

Hmmm. I always do that anyway to keep mechjeb from collapsing my parachutes.... (sometimes I have to do that because I'm low on fuel or I'm landing something so heavy that I'm using chutes and retros)

MechJeb 2 had to line up with the docking port. Starting at 100 meters gives it more time to adjust and maneuver. Starting at 40 to 50 it had no time at all and even had to back off or hold position. It starts to rock, twist and turn as it tries to do in 50 meters what it was designed to do in 100 meters.

It was totally due to my idea that I was saving time and fuel by getting it closer that it was freaking out. But I was wrong in both counts and blamed the mod. Poor little thing.

I am wrong. I am sorry.

I start from 50 all the time. However, I give MJ2 a head start by going to each craft and controlling from the docking port that's doing the docking, targeting the opposing docking port and using the Smart A.S.S. (Engage the Smart A.S.S.!!!! sorry, had to say it...) to manually point towards the target. Do that on each craft. It worked better on versions of MJ2 prior to KSP .21.x but lately it tends to immediately drift while switching craft whereas before MJ2 would still be active on the inactive craft keeping its port pointed at you. Not sure why it's not doing it anymore I can still make it work if I turn on SAS afterwards and let it stabilize a bit.

[sarbian]

The default one can do that too. It depends of the TWR of the lander. I tried to fix it but then it wouldn't land on target.

Where was it, and do you know the TWR ?

[Cyda]

Just want to say a big thank you to everyone working on this mod, it has become so useful. I was having some serious fps loss the last few days but I'm now using Sarbian's .dll and it is back to 60 fps. Thanks you!

[Diche Bach]

Just want to say a big thank you to everyone working on this mod, it has become so useful. I was having some serious fps loss the last few days but I'm now using Sarbian's .dll and it is back to 60 fps. Thanks you!

I second that sentiment! This plugin is absolutely amazing. I've learned a good bit about physics and orbital mechanics (at an intuitive level at least) from KSP, and I can see that this mod will help me to learn even more. Pretty remarkable creation!

Do I understand correctly that, when I activate an auto-pilot feature, such as auto-ascent, the application will effectively execute a "perfect" sequence of maneuvers in the sense that it will not waste any fuel? If that is correct, then it seems to me that just watching what MJ does with your ship when you give it a particular problem is a huge way to learn more. I was operating from the basic premise that the gravity turn should be performed sometime after 10,0000 m. I basically understand what terminal velocity means, but I was nonetheless surprised to see Mechjeb making my gravity turn at like 5400 m. Very interesting!

What happened to the old parts? Any way to get them back?

It looks like you have yet to get an answer, and it is possible that I do not understand what has changed in 2.09. However, I have the impression that, the mod has been changed so that instead of a "Mechjeb part" that you stick onto a ship to give it MJ functionality, all of the stock command pods have been edited to include the MJ functionality.

I'm not actually sure how you get MJ functionality with non-stock command pods though, so if nothing else, me attempting to partially answer your question may prompt a response from someone who can explain for sure.

Edited August 5, 2013 by Diche Bach

[rancor1223]

Do I understand correctly that, when I activate an auto-pilot feature, such as auto-ascent, the application will effectively execute a "perfect" sequence of maneuvers in the sense that it will not waste any fuel? If that is correct, then it seems to me that just watching what MJ does with your ship when you give it a particular problem is a huge way to learn more. I was operating from the basic premise that the gravity turn should be performed sometime after 10,0000 m. I basically understand what terminal velocity means, but I was nonetheless surprised to see Mechjeb making my gravity turn at like 5400 m. Very interesting!

I'm pretty sure it's not fuel efficient. More like time efficient. I only use the auto-docking and it wastes RCS fuel. A lot. But in exchange, it's fast and precise (maybe not as fast, but really precise . I would say the same about rendezvous autopilot, it does it's thing as quickly as possible. But if I wasn't lazy, I would rendezvous using only 2/3 of fuel MechJeb would need. But it would take much more time orbiting around, waiting for encounter.

[Diche Bach]

I'm pretty sure it's not fuel efficient. More like time efficient. I only use the auto-docking and it wastes RCS fuel. A lot. But in exchange, it's fast and precise (maybe not as fast, but really precise . I would say the same about rendezvous autopilot, it does it's thing as quickly as possible. But if I wasn't lazy, I would rendezvous using only 2/3 of fuel MechJeb would need. But it would take much more time orbiting around, waiting for encounter.

Oh okay. So the fact that it is taking my 7 stage rocket that I've used a lot to put stuff into geosynch and out to Mun, and committing the gravity turn at 5.4km instead of 10 to 11 where I normally do it doesn't really mean that 5.4km is the "better" place to do that turn?

I get the impression that there are presently quite a few known problems with this version as it functions either with 0.21 KSP else with other mods? I have RemoteTech running, but not using the Flight Computer. I just had MJ fail me on an Ascent that I turned over to full auto right after launch (really just to see how it works). First it didn't prevent overheats and my central engine blew up. Next it didn't actually relinquish control of the throttle or attitude when I clicked "Deactivate Autopilot" and then finally it sent my rocket into a spin at about 30km that caused it to break apart and fall out of the sky. Can try replicate or provide more details as needed.