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[1.11.x] Anatid Robotics / MuMech - MechJeb - Autopilot - [2.11.0] [12th January 2021]


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On 9/3/2020 at 1:23 PM, Gilph said:

It's easier for me just to use Maneuver Planner to work around it. The only really tricky part is if the approach is so exact and I don't slow down in time, So when I do the match velocities at closest approach, i open the maneuver node editor and subtract 10 secs.

It seems like, recently, it will pick the "wrong" choice more often. I could even disable AP, do the workarounds to get like 1km away, enable AP, and it would make the node to match velocities and maintain the distance i specified, but that doesn't seem to work anymore. I look at some of the recent revisions in dev and noticed there were a few updates.to Rendezvous AP that streamlined things a bit, which may be causing it.

It's not terribly impactful, just need to validate the AP choices before going to the bathroom and finding out my vessel is out of fuel when I get back.

That's a valid method since it gets the job done, but the reason I use the Rendezvous Planner is that it has all the buttons for the functions you need right there, and it includes very helpful displays of your current orbit, the target orbit, your relative inclination, the time to the closest approach (only valid if closest approach is less than one orbit from now), and the distance at closest approach (also only valid if closest approach is less than one orbit from now).

I find that it has all I need to get within physics loading range of any vessel in any orbit, assuming the craft I am flying has enough delta-V to do the maneuvers required of it.

On the other hand, when using the Maneuver Planner to do the same task, I don't have any of the helpful information readouts in the same window (I could create a custom info window for that purpose, but I don't have to do that if I use Rendezvous Planner), and I have to go thru a drop-down menu every time I want to change functions (not that there's anything wrong with that for how many different things Maneuver Planner can do, but it's a hassle when the Rendezvous Planner doesn't make me do that).

On 9/8/2020 at 12:03 AM, DerekL1963 said:

When meausuring distance to a target between a target and a craft in atmospheric flight, it is the true distance (measured along the surface) or the chord?

As far as I know, when measuring distance between any two vessels, MJ will always measure the distance along a geometrically straight line between the two vessels control sources, or if you have set a docking port as a target, between that target docking port's origin point and the origin point of whatever you have selected as the control point on the vessel you are flying.

I don't know for certain how MJ calculates distance between the current vessel and a target surface coordinate, however I can think of two methods:
1. Straight line distance would be "good enough" for most purposes, so that might be what is used as it's easy to calculate. Running this calculation every frame would introduce a trivial and generally not noticeable amount of lag.
2. Distance between two sets of coordinates on a perfect sphere might also be used, as this removes most of the long distance error with the first method, however it is still easy enough to calculate that it should not cause any more lag than the first method.

I'm not sure which method it uses, but I would use method 2 if the vessel was landed or splashed down. Not sure which method to use for a flying or orbiting vessel and a set of surface coordinates.

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Hi there, thank you for the great work and dedication

Would like to know if its possible to integrate satellite guidance into mechjeb 2.

Lets say you are at the planet or moon where you want to deploy, maybe a drop down menu that you can choose where you are and have all the relevant fields etc Ap, Pe, AN, Dn, AoP, so that you can just enter it in there and execute maneuver?

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5 hours ago, Krymson Skorpyon said:

I have an Ascent Guidance question - why would you ever release boosters early?  I tried that a couple of times with my standard booster setup, and every time something hits something else and... well... NASA would classify the results as "rich in learning opportunities".

I asked the same question earlier, @sarbian told me it's for RO/RSS, not stock.

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4 hours ago, VoidSquid said:
9 hours ago, Krymson Skorpyon said:

I have an Ascent Guidance question - why would you ever release boosters early?  I tried that a couple of times with my standard booster setup, and every time something hits something else and... well... NASA would classify the results as "rich in learning opportunities".

I asked the same question earlier, @sarbian told me it's for RO/RSS, not stock.

I was looking at playing with "BetterSRBs" and would have expected to make use of this feature in stock, too. I had a cursory glance at the code and I'd say it is supposed to drop solids (or rather not count them as active engines) when the stage's remaining burn time drops below the configured threshold. I'm not sure on that last part, the glance was too cursory to determine what LastNonZeroDVStageBurnTime() actually returns. I'll try it when I restart the game next :)

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a noob to KSP and would not even be able to play without mechjebs help so i really like this mod. had no problems with mechjeb yesterday (9/17) but today i am having several minor issues. landing guidance keeps crashing. latest example i was targeting lesser flats on minmus circularized at 15km and mechjeb had me flat engines 1st into the side of a mountain.  the other issue is it seems to fly over the target then wastes gas by flipping a u-turn to try and come back to the target instead of looping the planet it again. in the scenario above it did that right before sending me headlong into a mountain at 2100m/s. OUCH.

 

the other issue i am having (more of a question) is it seems to miss minumus more than it catches it. sometimes i select minmus as target, do the Hoffman transfer and i get it. other times i do the exact same steps and miss it wildly. so i am not sure if i need to tell mechjeb to match planes 1st then transfer or if mechjeb does it itself during the transfer burn.

Edited by starsfan69
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3 hours ago, starsfan69 said:

 landing guidance keeps crashing. latest example i was targeting lesser flats on minmus circularized at 15km and mechjeb had me flat engines 1st into the side of a mountain.  the other issue is it seems to fly over the target then wastes gas by flipping a u-turn to try and come back to the target instead of looping the planet it again. in the scenario above it did that right before sending me headlong into a mountain at 2100m/s. OUCH.

Make sure you aren't running out of electric power before the burn is suppose to start.  I had this happen to me last weekend.  I forgot to deploy solar panels after undocking my lander.  After the deorbit burn I had the landing lights on and drained the batteries way too fast even though I was landing on the day side the final braking burn never started.

3 hours ago, starsfan69 said:

the other issue i am having (more of a question) is it seems to miss minumus more than it catches it. sometimes i select minmus as target, do the Hoffman transfer and i get it. other times i do the exact same steps and miss it wildly. so i am not sure if i need to tell mechjeb to match planes 1st then transfer or if mechjeb does it itself during the transfer burn.

The Hohmann transfer is supposed to do the plane change, but I find it rarely does it well.  From Kerbin orbit I usually just match planes first and then plot the Hohmann transfer.  I use MechJeb's maneuver node editor to tweak the transfer to put me at the Pe I want instead of using the default that is usually an intercept with the center of the moon or doing a correction burn after leaving orbit.

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15 hours ago, Tonka Crash said:

[snip]

The Hohmann transfer is supposed to do the plane change, but I find it rarely does it well.  From Kerbin orbit I usually just match planes first and then plot the Hohmann transfer.  I use MechJeb's maneuver node editor to tweak the transfer to put me at the Pe I want instead of using the default that is usually an intercept with the center of the moon or doing a correction burn after leaving orbit.

When I first installed MechJeb (like a month ago now)  I laughed several times as I watched my ship crash into the moon.  I think this is an odd behavior, but I have gotten used to adjusting the PE (using MechJeb) shortly after the Hohmann transfer maneuver nodes have completed.  I have also learned to turn off RCS for that adjustment as it is enough to mess up the intercept distance (usually shoot for a PE of 50k as that seems to be a good orbit distance for Minimus). 

I suppose if Sarbian wished, a closest approach distance could be added to the settings for the transfer.  But, frankly, I would prefer they keep working on some of the other code such as the rover autopilot.  It would be nice if one could set the rover auto pilot to stop at a the target instead of hitting it at whatever max velocity you had set (like the docking function does?).  Crashing a rover into my mining ship on Minimus at 10 kps was worth a laugh or two (yes, I had saved just before trying the rover autopilot).

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On 9/19/2020 at 5:31 PM, pmoffitt said:

 It would be nice if one could set the rover auto pilot to stop at a the target instead of hitting it at whatever max velocity you had set

It does (works for me :). Being MechJeb, you need to check what it's been told to do. The "To Target" button adds a waypoint at the target CoM with default values. Make sure that the radius is large enough to lie outside the structure and the target is not obstructed. MJ will stop (or at least try to) if the first speed value (speed at waypoint) is 0. The second speed value is the maximum speed on the way (or whatever is set in the speed control option if it's 0).

ixRkj5w.jpg

Watch the "Target Speed" in the rover window:

Spoiler

 

To get to a docking port on the other side of a craft, it would try to drive in a straight line. The docking autopilot does consider the vessel bounds, indeed, but also does not see anything else flying around.

Edited by HansAcker
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Salut à tous,

J'ai un problème avec Mechjeb, j'ai cherché (peut-être mal), mais je n'ai pas trouvé de solution.

Avec Steam, j'ai mis à jour le jeu vers la 1.10.1, j'avais débloqué tous les modules Mechjeb. Après cela, j'ai réinstallé mes sauvegardes et mes mods (y compris Mechjeb 2) avec CKAN .

Mon problème est le suivant, dans KSP, je n'ai que le module AR202 et il m'est impossible de trouver les autres modules puisque j'ai déjà débloqué les technologies liées aux modules Mechjeb ...

Comment puis-je mettre à niveau Mechjeb?

Merci de votre aide.

Sorry, today the game works fine ! I don't understand, perhaps a bug in KSP. Really sorry.

 

Edited by Fulcrum
Works fine !
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M78BhMs.jpg

Hi all

I keep getting this error with mechjeb "last failure converged optimizer iteration failed" and my rocket keeps pitching down non stop which I don't know if the error was the cause.

I hope someone would know what causes this error and if it's related to the rocket non stop pitching

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Better explanation of "Attach altitude" needed

As new features are not finding their way to the Wiki very quickly, the only information about what "Attach altitude" is I can find in the commit where it was implemented:
https://github.com/MuMech/MechJeb2/commit/a4a058aa8568cc510bb97875b8e6b05f117d0972

There it says:

Quote

add attach altitude to PVG

exposes an actually usable API to the flightpath angle constraint.

can be used to launch to 90x185 with the shuttle but attach at 120
to avoid burning up the orbiter.

I need a better explanation. Perhaps I have issues with understanding this shortened paragraph because english is not my native language.

Edited by Gordon Dry
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On 9/20/2020 at 1:10 PM, HansAcker said:

It does (works for me :). Being MechJeb, you need to check what it's been told to do. The "To Target" button adds a waypoint at the target CoM with default values. Make sure that the radius is large enough to lie outside the structure and the target is not obstructed. MJ will stop (or at least try to) if the first speed value (speed at waypoint) is 0. The second speed value is the maximum speed on the way (or whatever is set in the speed control option if it's 0).

ixRkj5w.jpg

 

@HansAcker Thanks, that helps and works much better.

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hi, I've recently reinstalled all, game and mods.
I've started a new career, I would like to launch the 2nd rocket into the 1st Kerbin orbit with mechjeb.
I use the scripting module in order to have access at the ascent guidance module but it doesn't work correctly as I remember:
it changes the AoA the right way but it no longer maximize the throttle when I press the "engage autopilot" button or gradually stop the throttle when the Ap is reached.
It has no more control of the throttle!
so can't I put my second career rocket in orbit with mechjeb?

I'm sure I've already used the ascent guidance in a early career game but I don't know what I have I forgotten this time.
I read something about edit some cfg files in order to enable all the MJ features since early career but I don't wanna talk about that.
I just want to know if this behavior is normal, is intentional or I am stumbled into a bug/glitch or if I have to unlock some building in order to have the throttle control.

 

Screenshot%202020-09-23%2011.44.56.jpg?d

 

it does burn all the fuel and when the ship reaches 70km the autopilot turns off.

Screenshot%202020-09-23%2012.26.05.jpg?d

Edited by antipro
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4 hours ago, antipro said:

I just want to know if this behavior is normal, is intentional or I am stumbled into a bug/glitch or if I have to unlock some building in order to have the throttle control.

If your tracking station is not upgraded then MJ can not use maneuver node. Without node available the ascent AP will not preform the circularization.

Edit: as for the throttle. Did you actually stage the engine ?

Edited by sarbian
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3 hours ago, sarbian said:

If your tracking station is not upgraded then MJ can not use maneuver node.

of course it isn't, I'm at the second career launch and I have no funds enough..

 

3 hours ago, sarbian said:

Without node available the ascent AP will not preform the circularization.

ok this make sense when the AP stops working at 70km. But why the engine does not stop when the Ap is reached?

 

3 hours ago, sarbian said:

Edit: as for the throttle. Did you actually stage the engine ?

excuse me, I don't understand. what it means?
I usually press ""Engage autopilot" then I press the spacebar key to activate the only engine.

Edited by antipro
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32 minutes ago, antipro said:

I usually press ""Engage autopilot" then I press the spacebar key to activate the only engine.

And after you pressed the space bar MJ did not set the throttle to 100% ?

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