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

[AbeS]

Like this:

@PART[*]:HAS[@MODULE[ModuleCommand],!MODULE[MechJebCore]] 
{
	MODULE
	{ 
	name = MechJebCore
	}
}

Copy and paste it in notepad, then save it like WHATEVER_NAME.cfg. Put it anywhere in the GameData folder and voila!

(Needs Module Manager 1.5.x)

[drtedastro]

Hello to all.

I have tried a search for problem / difference with displayed TWR, but either I have missed them or they are not listed.

I am running the latest and greatest dev build, #163, and I am seeing and finding large differences in the shown vs 'actual' TWR between VAB and launch in the delta V window and differences at the same time between delta V and Vessel window...

right after launch, deltaV window shows 1.97 and vessel shows surface TWR 1.25

What am doing wrong? or is there something here that i am missing...

many thanks for any info / help and thanks for such a great mod....

[AbeS]

Are you using Real Fuels? click on all stats and there is a column that shows the SLT (Sea Level TWR)

[drtedastro]

Are you using Real Fuels? click on all stats and there is a column that shows the SLT (Sea Level TWR)

Yes I am.. Thanks, I will check that out.....

Cheers.

[drtedastro]

Yes, that shows a difference. Actually now, that means I have three values. The deltaV TWR and SLT and then Vessel surface TWR, and all are different... what causes or what is the reason or calculation method(s) that are producing these various and very different values?

[sarbian]

Real Fuels change trust with altitude so you get :

- deltaV TWR : in space TWR

- SLT TWR : sea level TWR

- Vessel surface TWR : Current TWR

Edit : I checked the code.

I need to change the label

[drtedastro]

Real Fuels change trust with altitude so you get :

- deltaV TWR : in space TWR

- SLT TWR : sea level TWR

- Vessel surface TWR : Current TWR

Edit : I checked the code.

I need to change the label

Many, MANY thanks for the explanation. I appreciate you taking the time to explain this. I kept building craft that 'seemed' to have enough umph, but when launched they would just sit there and huff and puff......

cheers.

[sebi.zzr]

No offense,was just an idea.

[sonicsst]

Fixed for real in #163.

Great! Using this new level of precision and the thrust limiter I was able to align my Kerbin RT2 constellation such that it suffered less than 1 degree of drift over 100 days.

However, it seems to have introduced a new minor bug: when the minutes for orbital period should read 00 it instead shows the same value as seconds.

[sarbian]

duh

Ok, I'll look into it tomorrow.

I spent the evening working on some new code for the attitude controller (the module that turns the ship) after speaking with HoneyFox. After a bit of struggle I finally have something that looks like it work far better.

I'll test it more tomorrow but you should get it in a dev version soon. Thanks again HoneyFox

[Starwaster]

Return from Moon did not return me from the Mun. It probably should have done its while it was oriented prograde in the direction of the Mun's retrograde. That would have required a DV of about 200 m/s. Instead it plotted a 2000+ m/s burn on some bizarre vector on the other side of the planet.... but it didn't actually perform the burn there.... What I was left with was a high arc over the backside of the Mun ending in a lithobraking maneuver at the end. This part I did not enjoy.

[Virtualgenius]

I have been using the launch to rendezvous button and its really good gets within 60km of the target but it doesnt finish the job which is ok so select the rendezvous autopilot it then wants to do a completely different thing instead of a short burn to catch the target is this normal

[sebi.zzr]

I have been using the launch to rendezvous button and its really good gets within 60km of the target but it doesnt finish the job which is ok so select the rendezvous autopilot it then wants to do a completely different thing instead of a short burn to catch the target is this normal

yes it normal,it gets trough its protokol: matching planes>new orbit>hofman transfer>intercep target at closest aproach>fine tune distance to target.

[sarbian]

The Rendezvous AP won't do a direct burn unless you are at less than ( 600km (kerbin radius) + 60km ) / 25 = 26.4 km.

So this is normal and you get the full rendezvous protocol, which can't be a bit longer. I could add a "force interception burn" somewhere, we'll see.

[Tex_NL]

I have been using the launch to rendezvous button and its really good gets within 60km of the target but it doesnt finish the job which is ok so select the rendezvous autopilot it then wants to do a completely different thing instead of a short burn to catch the target is this normal

You only get to within 60km? MechJeb is more than capable of getting you within 5 km.

First launch to rendezvous like you've done before. When the launch guidance is finished do not switch to the rendezvous guidance. Instead, I know it may sounds strange, revert flight to launch. If you payed attention to your launch angle on the first launch you'll notice it has changed. Now launch again with the new updated launch angle to the same altitude and you'll get a lot closer.

[AndreyATGB]

If you're impatient you can just write 24°. It'll get you at least at <15km with basically any ship. Better obviously would be to revert flight after autopilot is done launching (don't disable it before it automatically deleted the node).

[LameLefty]

I never bother with launching to rendezvous, reverting, all that nonsense. I WILL launch into the plane of the target if it's more than a couple degrees off equatorial, but I'll launch into a substantially-different target altitude to make sure I'll get a decent phase angle pretty quickly. For instance, if my target is at 100 km, I'll launch to 150 km. If my target is at 300 km, I'll launch to 150 km - 200 km. Once you're in orbit and circularized, use the Rendezvous Planner to "Intercept Target With Hohmann Transfer" and use the Maneuver Planner to execute the node with auto-warp enabled. Within a couple hours' game time (a moment or two with auto-warp enabled), you'll be on a trajectory that intersects the target orbit within about 1 - 2 kilometers at most, sometimes less.

What I do then is go to map view and warp until I'm within about 3 minutes of the closest approach. I then change back to the flight view, make sure I can see my target on the navball and on-screen, and start "backing" in, slowing down and driving the target marker onto my retrograde marker with braking burns. I can execute a rendezvous this way with almost zero RCS usage if I have a medium sized vessel or smaller, and with Navyfish's Docking Port Alignment Indicator, I can do the final approach and docking manually quickly and reliably, with no need to hand over control to the auto-pilot and bite my nails.

MJ has a lot of wonderful and data and flight tools (precision parachute landing being the newest - thanks Sarbian and codepoet!) but I've never had much luck with auto-docking and auto-rendezvous. And once you know how to do it manually, using MJ to plan and execute the gross intercept burns makes the final manual steps very easy anyway.

[sarbian]

I committed the change to the attitude controller. Feedback is welcome. I did not test much with plane and I'd like some feedback with them.

Back to work. I need to fix the DHMS display, a bug about node execution and the VTOL thing from a few days ago.

LameLefty: the docking AP need more love. I left it in a half fixed state

[LameLefty]

LameLefty: the docking AP need more love. I left it in a half fixed state

No worries. There were bigger fish to fry and you've been doing a great job with them all, so far as I can tell. And again, for people who struggle with manual docking, once MJ puts you in a good trajectory for rendezvous (which it does very well with the Rendezvous Planner), the actual docking isn't very hard. It just takes a bit of practice, and other tools make it even easier.

But nudging around maneuver nodes and trying to get those phase angles right for the rendezvous burn is tedious and frustrating - MJ makes all that go away, and that I thank you very much!

[Starwaster]

I committed the change to the attitude controller. Feedback is welcome. I did not test much with plane and I'd like some feedback with them.

Back to work. I need to fix the DHMS display, a bug about node execution and the VTOL thing from a few days ago.

LameLefty: the docking AP need more love. I left it in a half fixed state

On the subject of docking AP, currently it tries to combine moving towards the docking axis and moving towards the dock with the same set of burns. I don't have a problem with that but it shouldn't use the same rate for both.

The further it is from the docking, the less it should be trying to move towards the dock. I think if 'move-to-dock' rate were made to be inversely proportional to 'move-to-docking-axis' that should yield good results. I think it would also fix issues that people have reported where it ends up at the dock off center. I didn't used to understand what they were talking about but I do now since I've been playing a little more where docking is required. The way it is now it's like it tries to move to the dock at a 45 degree angle and I end up turning the AP off, (with smartass set to kill ROT), RCS thrust backwards to slow my rate towards the dock and then turn it back on when I get closer to axis.

[sojourner]

It really should align docking axis before approaching within a certain distance. Someone made the suggestion a while back that it would be nice if this distance was assignable similar to the distance on the rendezvous autopilot. It would be useful for those tight docking situations.

[SupremeSoviet]

Does Autodocking actually work yet? I haven't given it a shot yet.

[CleverLikeMe]

Does Autodocking actually work yet? I haven't given it a shot yet.

It works fine. It isn't 100 percent perfect and docking very awkwardly shaped things doesn't always work (though it usually does as long as you line things up manually so they don't bump into eachother first).

The only time I've had to manually dock was when I had to orient the ship in one direction, move, then orient in another direction, then move and dock. But honestly I wouldn't expect mechjeb to handle that kind of situation anyways.

[Guest]

Does Autodocking actually work yet?

Yet? It's been working fine for ages.

[Neutrinovore]

It really should align docking axis before approaching within a certain distance. Someone made the suggestion a while back that it would be nice if this distance was assignable similar to the distance on the rendezvous autopilot. It would be useful for those tight docking situations.

I agree. The best thing would be to have an 'Aligned with Docking Axis by X Distance' field. Maybe that's not the best wording, but you get the gist. I have several ships and stations where a docking port is relatively close to fragile solar panels and radiators, etc., and I would like to move straight in from 10 or 15 meters out to avoid them.

I understand that this isn't a vital feature, but it sure would be nice to have.

And, @SupremeSoviet, of course it works, it has for a long time. What do you think we're all talking about in these last few posts?