[1.12.x] Anatid Robotics / MuMech - MechJeb - Autopilot - [2.14.3] [4th March 2023]

[Carl]

Xenon dosen;t respect crossfeed settings, the bottom stage will drain your upper stage. You can do multistage ion craft where you discarding empty tanks, but not where it's traditional multistage where you discard tanks plus engine/s. Ran into it during my DER 3 attempt.

[Foxster]

Just now, Carl said:

Xenon dosen;t respect crossfeed settings, the bottom stage will drain your upper stage. You can do multistage ion craft where you discarding empty tanks, but not where it's traditional multistage where you discard tanks plus engine/s. Ran into it during my DER 3 attempt.

Ah, I see.

In that case I just disable the upper stage tanks until the bottom ones are empty. 

[Carl]

I think it's because another part of the engine fuel, (electricity) dosen;t respect crossfeed, it bleeds into the Xenon and creates issues.

Edited January 18, 2017 by Carl

[sarbian]

No, it is the Xenon itself that creates the "issue" (it s not one, since MJ can't know when you ll activate/deactivate tanks manually)

[Carl]

I meant i terms of why in the base game Xenon doesn't respect cross feed settings, i think it's locked to the electricity cross feed setting ;).

 

Sorry for the confusion.

[sarbian]

No, AFAIK Xenon is set like that because one of the tank was surface attached and before 1.2 engines would not draw from surface attached tank for fuel that respects crossfeed.

[Carl]

Ahh fair enough. Cheers for the explanation btw.

Edited January 18, 2017 by Carl

[Mystique]

5 hours ago, sarbian said:

Without the vessel file and exact reproduction steps I can not debug the dV.

Sorry, just got back to KSP to do it.

I was able to recreate bug in this way only so far:

1. Build cargo for hauling (say, cupola+hitchhiker container).

2. Rotate it upside down - this seems to be 1/2 major steps.

3. Attach docking port or decoupler to cupola (seems to be same effect).

4. Build command pod and all other stuff below that docking port, including lifter stages.

5. Select command pod (normally facing) as new root - 2/2 major steps.

6. See that KER dV calculation (and TWR) is different from MJ as shown on screenshot.

6a. Strange thing is: if I detach lowest stage, dV/TWR reading become the same, when I put that stage back, MJs data becomes incorrect, though lower stages shouldn't affect dV/TWR of upper ones in any way.

Saving/reloading craft didn't help. Hotfixed by reattaching cargo (starting from stack separator, i.e. first part attached to new root).

Guess it's cause by MJ not updating new part hierarchy (wild guess, I dunno how it works under the hood anyway ).

Spoiler

 

 

Craft file on dropbox

Edited January 18, 2017 by Mystique

[Mokmo]

I'm looking at one of my tankers, it's having issues keeping a heading no matter what mode i use on the SmartASS. So i was wondering, as it's so big, would there be a way to change the PID variables for the specific ship so that it reacts a bit less strongly for heading changes ? Is there a tool showing the output values ?

It has plenty Reaction wheels and acts bad wether it's full or nearly empty. Not too sure what else could cause this... 

 

[Carl]

Pics, maybe even a craft file? We can't really help you without determining why it's happening.

@sarbian The whole RCS getting toggled on for rotation is happening with MJ,a nd having found smart rcs panel the toggle flag for it there appears to be completely non-functional for me. I assume the game writes the log as it goes, so log here.

 

Also a couple of other things that can give Mj docking issues. If the other craft has MJ on and is locked to a specific heading and you have a very anemic RCS on the docking craft it can;t match the targets rotation changes. Basically MJ dosen;t take any other MJ induced motion i the other craft into account. Slightly differing orbits might produce the same issue.

 

[dboi88]

Hi @sarbian first of all i'd like to give you a massive thank you for continuing to maintain Mechjeb. It's one of my absolute required mods, the first to be installed on any new game.

I've just started playing with planes and the spaceplane autopilot. I wanted to add another runway, the big flat grass strip at Baikerbanur. I've looked at the code on Github and from my limited understanding it seems that both the island and KSC runways are hard coded but there are also references to a .cfg file where we can add our own. I can see that file in the source but not in the release download or in my gamefolder once i've run KSP. Can you point me in the right direction?

Also i've been meaning to hit you up for a while. I'm going to put together a KSPedia entry for mechjeb and i'd like to know if you'd be interested in a PR to include in the mod once complete? 

You can see my previous work here.

[vans0051]

On 1/14/2017 at 9:52 PM, Carl said:

Try changing the conics mode, happens somtimes. Had that issue while running my DER mission, it would keep losing the target resulting in the node auto deleting resulting in having to start again.

No joy.  Changed conics draw mode and patch limit, still having the error issue.

[Carl]

As i've been doing my station building i've seen more of the docking issues. MJ absolutely has huge issues docking even mildly misbalanced RCS setups. The problem is that on all but perfectly balanced setups the thrust misalignments with CoG produces unwanted rotation during translations. The RCS fires to correct this. This induces unwanted translation. MJ fires to correct it, repeat ad infinitum. MJ eitheir needs to figure out exactly how misbalanced things are and then limit translation burn thrust values across the entire array to what the reaction wheels can compensate for whilst eliminating RCS for rotation. Or calculate individual thrust limits of each quad, (not even sure KSP would support this). Ideally both so if it's more unbalanced in one direction than the other it can combine both. Might even be worth implementing a docking planner where you can do each step one at a time. i think some issues would certainly be fixed by getting the axes more aligned before moving in.

 

Also seen a the odd example of won't dock where it gets constantly closer but never docks. Some i think are MJ goofs regarding bounding box and backing straight back then telling MJ to go in again nearly allways works in those cases. But some are clearly sum rounding errors as they occur only on very low power designs and don;t fix on retries. I suspect from observation that MJ miscalculates the time value by a tiny fraction of 1%, but because thats still tenths or even whole seconds, it creates problems.

[sarbian]

Did you do your test with the official or dev release ?

[Carl]

Official, given some of the issues being reported with the dev releases atm i stuck to the official release.

 

Also keep meaning to mention it, PHJ has a docking issue with MJ on the end of his Space ToG video if you haven't seen it allready.

[sarbian]

On 11/01/2017 at 1:49 PM, sarbian said:

Bugs

There is two version of MechJeb available

• The main version that we release once or twice per KSP version
• The dev version that gets a a couple or release per month, week or even days. It may also have more bugs than the main version since new features are added

The dev release gets all the new features and bugs fix and the main version gets them when a new KSP version is released (or major bugs requires it). If you experience a bug the first thing I advise is to try the dev release. You can read the change log of the dev release here.

 

[sarbian]

On 20/01/2017 at 2:31 PM, dboi88 said:

Hi @sarbian first of all i'd like to give you a massive thank you for continuing to maintain Mechjeb. It's one of my absolute required mods, the first to be installed on any new game.

I've just started playing with planes and the spaceplane autopilot. I wanted to add another runway, the big flat grass strip at Baikerbanur. I've looked at the code on Github and from my limited understanding it seems that both the island and KSC runways are hard coded but there are also references to a .cfg file where we can add our own. I can see that file in the source but not in the release download or in my gamefolder once i've run KSP. Can you point me in the right direction?

Also i've been meaning to hit you up for a while. I'm going to put together a KSPedia entry for mechjeb and i'd like to know if you'd be interested in a PR to include in the mod once complete? 

You can see my previous work here.

I forgot to answer that earlier but

 

YES

[dboi88]

15 minutes ago, sarbian said:

I forgot to answer that earlier but

 

YES

Cool. Will let you know when done. It'll be a few weeks. 

In the meantime. Any help with adding that runway would be appreciated.

[sarbian]

4 minutes ago, dboi88 said:

In the meantime. Any help with adding that runway would be appreciated

Drop this file in your install and edit it to add what you want. MJ will load it. It also auto imports RSS and KerbTown/Kerbal-Konstructs launch site

You can add a custom info item "Lat/Lon/Alt Copy to Clipboard" (misc category) to help you to get the info to add in the file.

[dboi88]

4 hours ago, sarbian said:

Drop this file in your install and edit it to add what you want. MJ will load it. It also auto imports RSS and KerbTown/Kerbal-Konstructs launch site

You can add a custom info item "Lat/Lon/Alt Copy to Clipboard" (misc category) to help you to get the info to add in the file.

Thanks for this, this is working perfectly. No more air drops for the base at 'Baikerbanur' We can now bring in the heavy cargo planes and the superfast jets!

[Virtualgenius]

Do you drop that file in the gamedata root file or in the mechjeb folder

[sarbian]

Anywhere. You can even have multiple file and they would all be loaded. Mod could each ship theirs.

[rsparkyc]

Ok, weird issue i'm having, but for some reason, when I tell mechjeb to activate the next maneuver node, it does it immediately.  I'm playing on an RSS install (https://docs.google.com/spreadsheets/d/19_dhwSioZODCCtMFD0kZOtbmbg--ryoE0nzoWJL2cRc/edit#gid=523836116), and have checked the RO/RSS special handling checkbox.

EDIT: Nothing in the logs, but if I tell the scripting module to execute the node, it works just fine.

Edited January 25, 2017 by rsparkyc

[Nicias]

This is a feature request.

I've lately been docking manually using the target relative velocity information and either SAS or SmartASS set to target. 

However, if the target is not able to track the active docker, then you sometimes end up coming in pointing at the docking port, but it isn't pointing right at you.

Would it be possible to have a SmartASS target that is "parallel to target heading"?

[edit] Nevermind, I need to RTFM.

 

Edited January 25, 2017 by Nicias

[Fat Gordy]

Using the latest Dev build, 685, I'm experiencing a minor annoyance.  Whenever I create a new ship design in the VAB and launch it, MechJeb seems to forget which windows I had opened from the previous ship.  It's like it is defaulting to all windows closed (except DeltaV, which I had opened in the VAB).  I have to re-open each of the MechJeb windows every time I launch a new ship design.  When I re-open them, they open in the correct locations, but it's just a pain to have to re-open them each time.  Is there any way for me to change the default open windows? Thanks for any tips.