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

[a__gun]

I missed a few transfer over it too.

Good to know you still get time to actually play the game

[sojourner]

No, it's not intentional. You are sure this was not the case before ? At one point I thought my force roll patch added that bug, but reverting it did not change anything.

Anyway it's one of the bug on the top of my list, I missed a few transfer over it too.

Yeah, I've noticed that SMART ASS doesn't get disabled when other mechjeb functions are used, instead the other modules sit there fighting it for control of the craft.

[Jason Cox]

Has anyone else noticed an issue where MJ continues to try to burn the engines even when it's reached 0.0 m/s on the maneuver node (and should be auto-switching to the next one)? It's an odd bug that I haven't seen before I downloaded KSP 0.22 and MJ 2.1 the other day.

My mods are MechJeb, KW Rocketry, Kerbal Attachment System, Kethane, B9 and Procedural Fairings incase anyone is aware of any issues with MJ interacting with them.

[tfm]

MechJeb WILL burn forever when you have the wrong "control from here" area set. Example, if you have the docking port at the top set as the control point then MJ will burn the engines while the marker gets farther and farther away. I've lost a few ships to that.

[Jason Cox]

Hmm, I'll have to look into that. In the past that was never an issue and I could select any point on the stack as the control point... But hey, whatever gets my ships in orbit works for me!

[ThreeWholePunch]

Hi,

A few questions / comments.

1) Thank you for your continued support for this mod, I don't know how my feeble mind would play this game without the data and controls this mod provides.

2) I was using mechjeb prior to .22, upgraded to .22, noticed mechjeb functions no longer worked on my vessels, so I downloaded the .22 compatible version. I notice now that I need to add the mechjeb parts to my ship. That's unfortunate for my existing ships as the program just worked for them prior to the upgrade. My question here is, did I do something that allowed mechjeb to work without it's parts in the prior build and I just forgot that I did something to make that happen, or was mechjeb changed to require it's parts?

3) I've been trying to make sense of mechjebs auto landing. My goal is to land next to a target, another ship on the mun if you will. I know that mechjeb is so accurate that it crashes right onto the target I set, which is not good for the kerbals directly below. I've been playing around with the coordinates settings post-set target. I am always either too far or not far enough. My question is, is there an ideal coordinate change that would put me just a couple meters away from the target? Let's use the Mun for this example because I assume the answer would be different for each body.

Thanks again

[FellipeC]

For some reason when activate dock auto pilot here, the ship just aling with the docking port but don't fire the RCS.

Found the problem: Kerbcom Avionics. Removed that and worked as before.

[Galane]

The solution to MJ continuing to idle engines after a node seems to usually be adding more power. Throw 2 or 4 of the little orange radial mount engines on and see if it still does it.

On my 32K unit kethane lander I put four of the large white radials on and it could make it up and down from Mun OK, a bit slowly on the ascent with a full load, and most of the time it wouldn't shut the engines off after circularizing. So I added 8 of the small orange radial mounts. Burns about the same fuel, uses less corrective steering and shuts the engines down properly after making orbit.

Still not quite perfect because to ensure it can make rendezvous at 15KM I have it sit there and make some fuel. Should try taking everything down to 10KM.

[BurningSky93]

I think the spaceplane guidance could use some work (or its perfectly possible I'm not using it in such a way to get it to behave the way I'd like).

What I'm specifically referring to is the "yo-yo"-ing or "sine waving" it does when attempting to hold heading and altitude. When told to hold altitude, it will often climb so steeply that it overshoots the target altitude and to compensate will enter a dive that is also too steep and overshoot in the opposite direction before repeating the process. It would be great if it would begin to reduce climb/dive rate in such a way as to prevent this (or at least make it much less noticeable). It does iron itself out over time, but only after quite a few cycles and it never quite attains level flight.

Edited October 29, 2013 by BurningSky93

[Secret Squirrel]

Just a quick thank you for locking some of the features in career mode. Tried docking a few times, rage quit and used the autopilot. Well now the autopilot is disabled and I found myself needing to dock. I sucked it up and attempted it again and surprise!! first try got it. If it wasn't locked I would never have found out I know how to dock without it lol

[sarbian]

@BurningSky93 Someone submitted a patch that improve that. It upgraded the landing part too. I'll merge it at one point, but it's not on the top of my list for now.

@Secret Squirrel It's easy to be dependant on MJ. It's good to try without it

It just merged 2 new patch into dev :

The first one is to close the windows that are not researched yet. No cheating ^^

The second one is a patch by Numerobis and me. It improve the way MJ see engine that do not thrust parallel to the ship axis. p

I added a toggle to change how the Delta-V display this.

A good example would be the stock "Super-Heavy Lander". Its engine are tilted, so part of their thrust don't help pushing the ship forward.

Without (as usual)

With

Putting an engine in front will lower dV with this patch. I don't know if it's useful or not.

[BurningSky93]

@BurningSky93 Someone submitted a patch that improve that. It upgraded the landing part too. I'll merge it at one point, but it's not on the top of my list for now.

Is the patch available separately? If so, do you know where I can find it?

[LameLefty]

The second one is a patch by Numerobis and me. It improve the way MJ see engine that do not thrust parallel to the ship axis. p

I added a toggle to change how the Delta-V display this.

A good example would be the stock "Super-Heavy Lander". Its engine are tilted, so part of their thrust don't help pushing the ship forward.

These off-axis thrust losses are called "cosine losses" because the magnitude of the effect varies with the cosine of the angle. Anyway, glad to see you guys are trying to take it into account.

[sarbian]

@BurningSky93 https://github.com/sarbian/MechJeb2/pull/1

[rosenkranz]

Dag nab it! The MJ tab in the editor and in flight has hidden itself and I can't get it back. I tried deleting the global cfg file so it would rebuilt it but that didn't work. Any suggestions?

Hmmmm, 99 might not be stable. The menu tab keeps disappearing in the flight scene and then won't come back. Had to restart the comp to get it back in the VAB but then it disappeared when switching to the launch pad.

Edited October 30, 2013 by rosenkranz

[Galane]

Fly this little all stock rocket with ascent guidance. http://pastebin.com/0qpSi2cS

The first stage burns, the second lights then immediately MJ moves the Separatrons to the same stage and lights them too. There is no structural failure! It doesn't matter if "there's no code to do that" in MechJeb, it does it anyway. That's what bugs in software do, things you do not expect and did not intend to happen.

This is with the DLL in MechJeb2-2.1.0.0-98.zip

Fix this and I bet a lot of "structural failures" that are actually caused by MJ lighting up engines when it shouldn't will go away. Like I've said before, the triggers seem to be a stage with a low TWR and/or engines without a decoupler in their stage.

With this small test rocket, it's not low TWR. The Separatrons don't have decouplers in their stage. I was attempting to see if MJ would use them to attempt to get into some sort of orbit but I've launched it several times and every time it lights them up instead of waiting for the 2nd stage burnout.

[NathanKell]

Again, NO. They are not moved. What happens is MJ _immediately stages again_. As it should, since it says "aha! I have more engines I can activate! Let me do so!" It just doesn't check whether they're pointing in the right direction, or whether you, the omniscient designer, decided "no I want MJ to not fire these engines now, even though they are available and sitting around wasting dry mass until fired."

Same thing with procedural fairings: Since there's no fuel behind the decoupler, MJ thinks they're just wasting mass and thus decouples them ASAP. (Though IIRC this one got special handling and doesn't happen anymore?)

What _actually_ happens is the engines that are currently firing, because they are not decoupled on that stage event, are "brought up" to the currently active stage graphic. Notice the stage # in the lower left next time. When the LFE fires, it'll say 4 (for example); when the separatrons fire immediately afterward it'll say 3 (again for example).

It happens *only* when:

MJ finds a stage above the current stage, the activation of which will not decrease the current stage's dV. (Since the separatrons _add_ dV, though in the opposite direction, this returns true and the stage is activated).

[sojourner]

I bet a lot of "structural failures" that are actually caused by MJ lighting up engines when it shouldn't will go away.

I don't believe there are "a lot". Seems to be just you.

With this small test rocket, it's not low TWR. The Separatrons don't have decouplers in their stage. I was attempting to see if MJ would use them to attempt to get into some sort of orbit but I've launched it several times and every time it lights them up instead of waiting for the 2nd stage burnout.

Use the "stop at stage" function in the ascent pilot and try testing this rocket again.

Edited October 30, 2013 by sojourner

[Corbald]

I'm having similar issues. I updated in the hope that my craft would stop spinning out of control when ascent autopilot was in charge and when at very low, downward velocity and retro is nearly straight up. Deleted old Mechjeb folder and installed latest from GitHub. now have no menu and the light on the MechJeb module is red. I believe what's happening is that I have already unlocked MechJeb in the tech-tree, but the .cfg files don't concur. Can anyone tell me which entries to edit to make it recognise I have unlocked up to 'Unmanned Tech?'

Dag nab it! The MJ tab in the editor and in flight has hidden itself and I can't get it back. I tried deleting the global cfg file so it would rebuilt it but that didn't work. Any suggestions?

Hmmmm, 99 might not be stable. The menu tab keeps disappearing in the flight scene and then won't come back. Had to restart the comp to get it back in the VAB but then it disappeared when switching to the launch pad.

[Galane]

Again, NO. They are not moved. What happens is MJ _immediately stages again_. As it should, since it says "aha! I have more engines I can activate! Let me do so!" It just doesn't check whether they're pointing in the right direction, or whether you, the omniscient designer, decided "no I want MJ to not fire these engines now, even though they are available and sitting around wasting dry mass until fired."

Same thing with procedural fairings: Since there's no fuel behind the decoupler, MJ thinks they're just wasting mass and thus decouples them ASAP. (Though IIRC this one got special handling and doesn't happen anymore?)

What _actually_ happens is the engines that are currently firing, because they are not decoupled on that stage event, are "brought up" to the currently active stage graphic. Notice the stage # in the lower left next time. When the LFE fires, it'll say 4 (for example); when the separatrons fire immediately afterward it'll say 3 (again for example).

It happens *only* when:

MJ finds a stage above the current stage, the activation of which will not decrease the current stage's dV. (Since the separatrons _add_ dV, though in the opposite direction, this returns true and the stage is activated).

It's still burning engines in different stages at the same time, which should not be allowed to happen. The engines have been placed in different stages for the purpose of the higher stage being activated only *after* the fuel runs out in the lower stage.

Doing something that should not happen is a bug in the software.

[Galane]

Use the "stop at stage" function in the ascent pilot and try testing this rocket again.

Of course that works *but* it defeats the purpose of placing the engines in different stages that are supposed to be activated one after the other *in series*, waiting for all the fuel in each stage to be consumed *before* activating the next stage.

[Irwayz]

I'm having similar issues. I updated in the hope that my craft would stop spinning out of control when ascent autopilot was in charge and when at very low, downward velocity and retro is nearly straight up. Deleted old Mechjeb folder and installed latest from GitHub. now have no menu and the light on the MechJeb module is red. I believe what's happening is that I have already unlocked MechJeb in the tech-tree, but the .cfg files don't concur. Can anyone tell me which entries to edit to make it recognise I have unlocked up to 'Unmanned Tech?'

I am having this same problem with build 99. it changes the value in "mechjeb_settings_global.cfg" under "MechJebModuleMenu" then "enabled = True" it changed this to false when loading the menu for the first time If your really quick you can see it appear then hide really quickly. 98 seems not to do this. it an issue with the .dll maybe?

[NathanKell]

Galane, you continue to not read our responses to you. They are not in different stages. Mechjeb stages the same way you do when you hit space. If you hit space in the same circumstances, the separatrons would fire the same way, your currently active engines would be brought up to the stage the separtrons are in because you staged to that stage. If you don't want it to autostage (what you told it do do) then turn off autostage.

The one thing not working as designed here is that MJ doesn't determine what direction an engine's thrust transform points in.

What you suggest (not staging until fuel exhausted) would break asparagus launchers, which depend on staging away things as soon as they no longer contribute to the flight. In fact, it would break any kind of parallel staging, whether crossfed or not, because, oh well, can't stage away anything until the core runs out of fuel!

Edited October 30, 2013 by NathanKell

[Simplicity]

Dag nab it! The MJ tab in the editor and in flight has hidden itself and I can't get it back. I tried deleting the global cfg file so it would rebuilt it but that didn't work. Any suggestions?

Hmmmm, 99 might not be stable. The menu tab keeps disappearing in the flight scene and then won't come back. Had to restart the comp to get it back in the VAB but then it disappeared when switching to the launch pad.

Yup, hap[ened to me as well, no more Mechjeb tabs in vab or launchpad. Using #99 as well.. - I reverted back to #98 and the mechjeb tabs show up with no problems, seems maybe something in #99 has broken

[sarbian]

#100 should not hide your tabs