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[1.7.x] Anatid Robotics / MuMech - MechJeb - Autopilot - [2.8.4] [14 June 2019]

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Can Mechjeb due orbital maneuver burns with just RCS?  

I built a small probe that uses monopropellant and and the stock place anywhere thrusters for its main propulsion.  I can use mechjeb to plot a new maneuver node, Kerbal Engineer will show the total dV of the RCS system but when the I hit the maneuver node nothing happens.  I can do the nodes manually but not with MechJeb.  Is this  a limitation of Mechjeb or am I doing something wrong?

 

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Yes it can.

  • Set throttle to zero.
  • Bring up the SmartRCS MJ module and turn on the option to use RCS when thrusters are offline.
  • Turn on RCS (toggle with "R" key).

And you're ready. Personally, I keep RCS off until after I've finalized the maneuver node and oriented by probe to the maneuver using SAS. Otherwise, things get jerky. Also, depending on the mass of your probe, set the RCS max throttle to a low value.

Don't forget to turn things off after the maneuver is complete. Otherwise, MJ will use RCS for any sort of maneuvering and use up all your propellant.

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On 6/14/2019 at 1:31 PM, steddyj said:

/facepalm  

I just understood why this config file exists, and why it broke the old MechJebForEverything file I had been using since forever.  Although now that I understand the conditions you're trying to create, shouldn't the second block NOT include !MechJebUseCommandPod if you want it to trigger if both are flagged? 

For that matter, shouldn't the only NEEDS there be MechJebUnlocked?  As written it will explicitly ban anyone from using this method to unlock MechJeb in an RSS/RP-0 environment, which is fair enough, but since this already requires some minor acrobatics to accomplish and won't provide any feedback as to why it doesn't work in those use cases, couldn't it be assumed that someone who wants to use this option understands that it bypasses the spirit of RP-0?  This is mostly my opinion as an admitted cheater.  But also, I spend a lot of my life working out ways to not have users contacting me for support.  

- I think that it gets it correctly in all cases, because the first block is responsible for adding or not adding mechjebcore to all the command pods.  then the second block is responsible for overwriting all the unlock settings on all the mechjebcore modules.

- RP-0/RealismOverhaul already adds mechjeb to all command pods and unlocks it all from the start, so this code disables itself and lets RP-0/RealismOverhaul handle it:

https://github.com/KSP-RO/RealismOverhaul/blob/master/GameData/RealismOverhaul/RO_RecommendedMods/RO_MechJeb.cfg

(plus a bunch more references to MechJebCore scattered around the configs)

https://github.com/KSP-RO/RP-0/blob/6fb9c62edc1d467d01275b2030993e4aaf17a5b7/GameData/RP-0/Tree/ProceduralAvionics.cfg#L24-L46

there's some work going on right now to have MJ disabled when avionics are insufficient + disabled which is more the kind of integration that RO/RP-1 players want.

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@Jim DiGriz Ah, gotcha.   I'm aware of RP-0 and RSS but don't use them, so I wasn't aware that they unlocked MJ from the start. The procedural avionics stuff seems interesting.

I can confirm that build 886 lets me cheat to my heart's content. Thanks!

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Posted (edited)

Is anybody tracking the career mode issue with features not turning on based upon the R&D tree activating correctly.  Particularly, under Advanced Flight Controls, Maneuver Planner is not activated during flight.

Please ignore the NUB question... Solved my own problem

Edited by Syd V

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Posted (edited)

If someone is interested, I made some progress on landing on atmospheric planets. It connects MechJeb with KSPTrajectories for target predictions as most players do.

It is still highly experimental, only debug builds work as I still have stuff left in that section within KSP Trajectories. You can pull current work from https://github.com/cbase2/MechJeb2 and https://github.com/cbase2/KSPTrajectories/tree/retro.

I tested simple rockomax first stage with direct retrograde landing, rockomax and kerbodyne angled reentry using deployed control surfaces at tail which act as canard on retrograde entry. All landed at runway or KSC, but still may need more or less fuel depending on educated reentry parameters for PE and target undershooting Trajectories predictions.

However canard attitude control seems not working, so I had to disable all controls and manually adjust deploy angle to keep pitch. This is what I am currently working on, so I can simply enter some angles in Trajectories and MechJeb uses canards to follow it. My fault, for control surfaces in retrograde use, you need to set authority to negative values, even with manual control.

Next is to alter Trajectories pitch angle to improve aerobraking instead of thrusters use.

 

 

Edited by CBase
more expierence

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Posted (edited)

@CBase wow this sounds awesome, I cannot wait until you release something stable

 

Currently my experience with precise powered retrograde landing in atmosphere using MechJeb 2.8.4.0 is:

  • Between the deorbit burn and the atmospheric entry, sometimes (maybe depending on starting altitude, or target latitude, but not sure) MechJeb will enter a bad state and start burning full throttle along the normal vector; stopping Landing Guidance, time-warping a few minutes and re-starting Landing Guidance usually "fixes" it
  • Between the deorbit burn and the atmospheric entry, MechJeb seems to be switching between two trajectory models; one undershoots the target and the other overshoots it, so MechJeb is constantly alternating between two opposite course corrections; as a result, the vessel wiggles and does not make any course correction; this can be "fixed" by time-warping to atmospheric entry (EDIT: because, as long as the initial altitude is not too high, any offset can be corrected by RCS during atmospheric descent)
  • Atmospheric descent is mostly unpowered and uses aerobraking (because MechJeb figures the terminal velocity will be low enough?)
  • During atmospheric descent, the "Use RCS for small adjustment" option does a great job at keeping the predicted landing at a few tens of meters from the target
  • However, the braking maneuver just before the Final Descent phase is cut short and does not cancel all horizontal velocity, so I always end up overshooting the target
  • I "work around" this by using parachutes with a carefully-selected deploy altitude (depending on the initial and target altitudes), so that they deploy precisely above the target; it seems that parachute deployment prompts MechJeb to properly cancel horizontal velocity
Edited by nmc

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Sorry if this has been asked before, but is there a way to re-enable the G limiter?

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I did make some progress to decrease fuel usage by changing descend angles:

I did release some preview builds to test:

https://github.com/cbase2/KSPTrajectories/releases/tag/AtmoLanding_0.1

https://github.com/cbase2/MechJeb2/releases/tag/AtmoLanding_0.1

Known Issues:

  • Deorbit optimization is distracted by turning control surfaces as Trajectories takes their current angle into account -> Disable and reenable bevor hitting atmosphere
  • Course Corrections sometimes is highly unstable -> very distracting as Angles jump wild, still hits KSC usually

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Posted (edited)

is there a way to make MechJeb scripting work to program commands to a probe prior to losing a comm link?  The main thing I like about remote tech is the relatively easy way you can program a series of maneuvers into the "flight computer" and the probe will execute the maneuver even if it loses its comm link. 

 

Can MechJeb's scripting work in the same way or is the only way to get the same effect is to change the ksp settings to allow for probe commands without a link.

 

Edited by Galland1998

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I didn't know that it's possible to create MechJeb scripts. So much to learn... If you can assign a MechJeb script to an action group, the SmartParts mod has a part that can invoke an action group when the CommNet connection starts to drop.

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@Jim DiGriz @sarbian I've tripped over a very weird Breaking Ground bug with the Rover Stability Control function. I found the problem in a modded game, but was able to reproduce it with in a stripped install of 1.7.2 with only Breaking Ground, Module Manager, and MechJeb #889 installed. To the best of my knowledge this has been a problem since 1.7.1  across all MechJeb updates since then. It was only today I got around to narrowing down the problem.

If you engage the Rover Autopilot Stability Control, something is throwing off MechJeb at low velocities. From the video you can see the Requested Attitude Arrow is pointing up and a little left of center at zero velocity. As the rover moves forward it changes to down and a little right. Once it speed is up high enough it settles down to what it should be doing.  Just toggling Rover Stabilility Control ON for a parked rover in low gravity is enough to flip it over. It was a bit of a rude surprise the first time it happened.

All problems go away without the Scanning Arm on the craft. Moving the location of the scanning arm around the rover changes the Requested Attitude vector at zero velocity but I haven't figured out how to get rid of it.

This is the craft file that reproduces the problem I could provide logs, but I'm not seeing any errors or warnings so I doubt there's anything useful there.

 

 

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On 6/25/2019 at 4:52 PM, Tonka Crash said:

I've tripped over a very weird Breaking Ground bug with the Rover Stability Control function. I found the problem in a modded game, but was able to reproduce it with in a stripped install of 1.7.2 with only Breaking Ground, Module Manager, and MechJeb #889 installed. To the best of my knowledge this has been a problem since 1.7.1  across all MechJeb updates since then. It was only today I got around to narrowing down the problem.

If you engage the Rover Autopilot Stability Control, something is throwing off MechJeb at low velocities. From the video you can see the Requested Attitude Arrow is pointing up and a little left of center at zero velocity. As the rover moves forward it changes to down and a little right. Once it speed is up high enough it settles down to what it should be doing.  Just toggling Rover Stabilility Control ON for a parked rover in low gravity is enough to flip it over. It was a bit of a rude surprise the first time it happened.

All problems go away without the Scanning Arm on the craft. Moving the location of the scanning arm around the rover changes the Requested Attitude vector at zero velocity but I haven't figured out how to get rid of it.

This is the craft file that reproduces the problem I could provide logs, but I'm not seeing any errors or warnings so I doubt there's anything useful there

That should probably get turned into a bug report: 

https://github.com/MuMech/MechJeb2/issues

Right now I know I don't have time to investigate, and I'm guessing sarbs doesn't either.

Kind of vaguely hoping that one is a bug in KSP and it magically gets fixed because it looks weird and seems to be tied to that specific part.  Either that or there's something unique about that part which exposed a bug in MJ.

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so is this a new mechjeb?

 

Like right now I have MechJeb2 with the mech jeb modules looking like Radios with a red a green light.

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4 minutes ago, Dr. Omicron said:

so is this a new mechjeb?

 

Like right now I have MechJeb2 with the mech jeb modules looking like Radios with a red a green light.

I'm use the latest Dev branch build that updates much more frequently than the "official" release branch. At some point over the last few month a patch was added to just include MechJeb in all command pods without the need to mount the radio looking MechJeb unit. The first post in this thread describes how to get the Dev branch builds.

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8 minutes ago, Tonka Crash said:

I'm use the latest Dev branch build that updates much more frequently than the "official" release branch. At some point over the last few month a patch was added to just include MechJeb in all command pods without the need to mount the radio looking MechJeb unit. The first post in this thread describes how to get the Dev branch builds.

Yes I have that feature so it looks like im on the same one

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Posted (edited)

Need some help. So I upgraded to an ssd and re-added my mods for KSP but I get this error "part missing EngineerChip.Engineer7500, mumech.mj2.ar202." I think it has to do something with MechJeb.

-Thanks

Edited by Iceman9112

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Posted (edited)
On 6/30/2019 at 5:37 AM, Iceman9112 said:

Need some help. So I upgraded to an ssd and re-added my mods for KSP but I get this error "part missing EngineerChip.Engineer7500, mumech.mj2.ar202." I think it has to do something with MechJeb.

-Thanks

Hey Iceman, nice to meet you. Welcome to the community :)

When you're reporting a bug like this, it's usually helpful to include some logfiles. What exactly these logfiles are called, and how to find them is explained here -

(Click on the bold text "How to get support". You'll need to scroll down a bit)

 

Edited by El Sancho

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On 6/30/2019 at 10:37 AM, Iceman9112 said:

Need some help. So I upgraded to an ssd and re-added my mods for KSP but I get this error "part missing EngineerChip.Engineer7500, mumech.mj2.ar202." I think it has to do something with MechJeb.

-Thanks

Looks like a part from this Mod:  Kerbal Engineer Redux

 

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Posted (edited)
1 hour ago, Kampfsanni said:
  On 6/30/2019 at 4:37 AM, Iceman9112 said:

Need some help. So I upgraded to an ssd and re-added my mods for KSP but I get this error "part missing EngineerChip.Engineer7500, mumech.mj2.ar202." I think it has to do something with MechJeb.

-Thanks 



Looks like a part from this Mod:  Kerbal Engineer Redux

 

Actually, since it mentions parts from *both* KER and MJ, I bet it has something to do with a messed up install of MechJeb and Engineer for All

@Iceman9112

 

Edited by Stone Blue

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Definitely encountering a bug of some sort...

I installed the latest version of mechjeb on my 1.7.2 build. Assent guidance into the plane of the moon works for the first launch...then I go to redo it and it launches on its own plane and not the one of the selected target (the moon).... It's warping to the launch time and then it doesn't match the plane of the moon... Any help would be greatly appreciated! 

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27 minutes ago, Philaphlous said:

Definitely encountering a bug of some sort...

I installed the latest version of mechjeb on my 1.7.2 build. Assent guidance into the plane of the moon works for the first launch...then I go to redo it and it launches on its own plane and not the one of the selected target (the moon).... It's warping to the launch time and then it doesn't match the plane of the moon... Any help would be greatly appreciated! 

This has been an intermittent problem for me since forever. I select Minmus as my target, and it launches with a 6-degree inclination, but not matched to that of Minmus. I keep telling myself that at some point I will conduct an orderly, methodical, well-documented investigation into this phenomenon, but I never get around to it.

At one point I had it working. I did that by deleting my MJ2 directory completely and re-installing from scratch, but now it's doing the same old thing again. Yet the fact that I cured it by doing something on my PC leads me to suspect that it may not be an actual bug in MechJeb.

TL;DR - happening to me too, and I don't know why. I are confused.

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1 hour ago, El Sancho said:

This has been an intermittent problem for me since forever. I select Minmus as my target, and it launches with a 6-degree inclination, but not matched to that of Minmus. I keep telling myself that at some point I will conduct an orderly, methodical, well-documented investigation into this phenomenon, but I never get around to it.

At one point I had it working. I did that by deleting my MJ2 directory completely and re-installing from scratch, but now it's doing the same old thing again. Yet the fact that I cured it by doing something on my PC leads me to suspect that it may not be an actual bug in MechJeb.

TL;DR - happening to me too, and I don't know why. I are confused.

I've heard mechjeb has like a craft learning ability... Not sure if that's true or not..but it's strange that it works on the first launch...woohoo...go back in and relaunch...nope, doesn't work correct anymore. I almost think it's a mod compatIbility issue...i think I still need the principia mod so I'll see what that does to mechjeb along with a new install of the mod... 

 

I mean it's not the end of the world.. I can eyeball it but I'd rather let the computer do it... Lol

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Posted (edited)
1 hour ago, El Sancho said:

This has been an intermittent problem for me since forever. I select Minmus as my target, and it launches with a 6-degree inclination, but not matched to that of Minmus. I keep telling myself that at some point I will conduct an orderly, methodical, well-documented investigation into this phenomenon, but I never get around to it.

At one point I had it working. I did that by deleting my MJ2 directory completely and re-installing from scratch, but now it's doing the same old thing again. Yet the fact that I cured it by doing something on my PC leads me to suspect that it may not be an actual bug in MechJeb.

TL;DR - happening to me too, and I don't know why. I are confused.

hi guys. i used to have this issue too. My solution is :

select your target.

in the ascent Guidance windows, before clicking on "Launch into plane of target", i ALWAYS put 0 in the textbox at the right of this button. and all is ok.

Actually, my only issue with mechjeb is node alignement with smart ass. I have to click 2 times to have it effective quickly. For some raison it takes severals seconds to align (seems it needs two passes).

hope it helps you.

 

Edited by LTQ90
forgot one word :)

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55 minutes ago, LTQ90 said:

hi guys. i used to have this issue too. My solution is :

select your target.

in the ascent Guidance windows, before clicking on "Launch into plane of target", i ALWAYS put 0 in the textbox at the right of this button. and all is ok.

Actually, my only issue with mechjeb is node alignement with smart ass. I have to click 2 times to have it effective quickly. For some raison it takes severals seconds to align (seems it needs two passes).

hope it helps you.

 

I did notice the first time after installing the mod it reverted to 0 then afterwards it was like -189....lol I'll try that! Do you just put 0 in the launch to plane of target or do you also put 0 in the inclination right below the altitude?

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