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

[gamerscircle]

Alright...

I gotta ask, I have been using MJ for a couple of years and I don't completely understand when or how to use the Launch to Rendezvous.  For example, if I had something on the KSC Pad and a station in orbit, can I use the AG to get that rocket [having the correct dV, etc] from the pad to a intercept?

[maja]

Just now, gamerscircle said:

Alright...

I gotta ask, I have been using MJ for a couple of years and I don't completely understand when or how to use the Launch to Rendezvous.  For example, if I had something on the KSC Pad and a station in orbit, can I use the AG to get that rocket [having the correct dV, etc] from the pad to a intercept?

Yes, you can. It works best for 0° inclination. Select your target and fill it's altitude in the propper field in Ascent Guidance. Press Launch to Rendezvous, stage to launch and wait for final circularization. You will be probably way off your target. It's all right. Revert to launch and repeat entire procedure, but don't stage to launch. This time will MJ wait for the right time to launch. The first pass is to assess the ship's final position in the orbit compared to the position of the target.

[Red Shirt]

I have uploaded my out_log file. Please look and see why second stage engine does not activate after separation using ascent guidance. Thank you for any help.

 

[Wintergreen]

On 24/10/2017 at 3:03 PM, Red Shirt said:

I read back 3 pages and only saw one reference to what it happening in my 1.3.1 game. Using Ascent Guidance, craft stages as it should and throttles up but next stage engine does not activate. I am using only stock engines in a Windows install. Yes I have staging checked. I've even tried adjusting the timing.

Also I have build #747, landing guidance set to target KSC still doesn't come close, though for me it undershot instead of overshooting like with earlier build. Which makes sense as I noticed the engine burning through most of the atmosphere descent.

One the positive side, I've manually landed on Mun a few times since updating to 1.3.1

The problem is that it only stages once with autostage now (in the dev version)

The workaround for it is having the engines in the same stage as your decouplers.

 

And for what it's worth, rover autopilot is also broke as of 1.3.1. I'm guessing that's for the same reason that landing guidance was broken...it's aiming for a target nowhere near the actual target.

[Red Shirt]

5 hours ago, Wintergreen said:

The workaround for it is having the engines in the same stage as your decouplers.

Thank you.

[Commissar]

@sarbian any idea as to what can help with my issue of massive overshoot with docking AP? was fine before. i mean, im testing with multiple craft, including some that worked prior. im using #747

https://drive.google.com/file/d/0B6wl084zbNzmNjEwODhhYmNGQTQ/view?usp=sharing

16 hours ago, Wintergreen said:

The problem is that it only stages once with autostage now (in the dev version)

The workaround for it is having the engines in the same stage as your decouplers.

 

And for what it's worth, rover autopilot is also broke as of 1.3.1. I'm guessing that's for the same reason that landing guidance was broken...it's aiming for a target nowhere near the actual target.

 

i think this is also affecting docking AP. had the dockign autopilot take mwe from within 20m of the dock, to over 200m away, on the opposite side of the target craft. (the targeting issue, not the staging issue)

 

 

Edited October 27, 2017 by Commissar

[Wintergreen]

9 hours ago, Commissar said:

@sarbian any idea as to what can help with my issue of massive overshoot with docking AP? was fine before. i mean, im testing with multiple craft, including some that worked prior. im using #747

https://drive.google.com/file/d/0B6wl084zbNzmNjEwODhhYmNGQTQ/view?usp=sharing

 

i think this is also affecting docking AP. had the dockign autopilot take mwe from within 20m of the dock, to over 200m away, on the opposite side of the target craft. (the targeting issue, not the staging issue)

 

 

I may have experienced that problem once in 747. Not entirely sure, though...docking works fine for me on almost every instance.

The time it messed up, I switched between ships during the docking process, and the one on autopilot just kind of RCS'd it's way hundreds of meters away until it lost it's target. In theory, and from the perspective of a game developer, it makes sense that swapping ships would mess it up.

Edited October 27, 2017 by Wintergreen

[Commissar]

8 hours ago, Wintergreen said:

I may have experienced that problem once in 747. Not entirely sure, though...docking works fine for me on almost every instance.

The time it messed up, I switched between ships during the docking process, and the one on autopilot just kind of RCS'd it's way hundreds of meters away until it lost it's target. In theory, and from the perspective of a game developer, it makes sense that swapping ships would mess it up.

not really. it's worked fine for me doing that before

[Jimbodiah]

Future Feature Request for landing assist:

 

Right now if you have a high TWR on your lander, the "land somewhere" is really agressive on it's descent; waiting until it can do the 95% throttle landing. If your ship does not have super powerfull reaction wheels or RCS, the craft is still at an angle when the landing assist is already trying to touch it down, the ship can not turn itself fast eough to get feet down at 90° and often times you have to manually take over or abort. Lowering the max thrust before starting the landing assist prevents this, but I would like to ask if it is possible to start the landing burn earlier so that it is not as agressive in the last part?  Maybe set a slider to choose desired engine burn for descent (50-95% instead of the fixed 95%) detect the TWR and not calculate for a 95% final burn if the time of the landing burn is under x-seconds long, I dunno?

Several versions ago there was a routine at the end of the landing that did a kill burn a few hundred meters above the surface and then did a straight down landing. The problem here was erratic behavior during this kill burn above the surface which is why it was removed I think? The current landing routine by itself is great I think, just maybe a little less agressive burn for high TWR ships?

 

Edited October 27, 2017 by Jimbodiah

[Daveroski]

1 hour ago, Jimbodiah said:

Future Feature Request for landing assist:

 

Right now if you have a high TWR on your lander, the "land somewhere" is really agressive on it's descent; waiting until it can do the 95% throttle landing. If your ship does not have super powerfull reaction wheels or RCS, the craft is still at an angle when the landing assist is already trying to touch it down, the ship can not turn itself fast eough to get feet down at 90° and often times you have to manually take over or abort. Lowering the max thrust before starting the landing assist prevents this, but I would like to ask if it is possible to start the landing burn earlier so that it is not as agressive in the last part?  Maybe set a slider to choose desired engine burn for descent (50-95% instead of the fixed 95%)?

Several versions ago there was a routine at the end of the landing that did a kill burn a few hundred meters above the surface and then did a straight down landing. The problem here was erratic behavior during this kill burn above the surface which is why it was removed I think? The current landing routine by itself is great I think, just maybe a little less agressive burn for high TWR ships?

 

Have you tried setting your engine thrust with the right click widget?

 

[Jimbodiah]

The UI you mean... Yeah, but it's kind of lame to do a landing, see what thrust is best and then reload to do the landing over again. The problem is that the craft needs to be able to rotate rather quickly just before touch-down using it's reaction wheels, to turn feet down in time. Lowering thrust makes the final part of the landing slower, giving more time for the craft to turn feet down as the last few meters are not as abrubt, but setting this manually on every landing is not practical and not the intention of an automated landing routine I think    

Also on lower TWR landers the angle at which you approach the surface is ofen much steeper (45-60°), meaning the lander is already pointing feet-down for the most part. On high TWT landers, the angle is much shallower (30-45°) meaning the feet are pointed retrograde instead of toward the surface, and does not enough time to turn feet-down as there is not much elevation left to do it.

Yeah you could add RCS or heavy reaction wheels, but this is a work-around as low TWR lands just fine without RCS or heavy reaction wheels (engine gimballing is all that is needed here mostly)
 

I can provide videos of both landings to Sarbian if he deems it noteworthy of future consideration.

Edited October 27, 2017 by Jimbodiah

[lekkimsm2500]

Sarbian, love the work as usual.

And i have a suggestion. I've been fiddling about with build 747, haven't updated for quite a while previous of that, and now noticed the wonderfully feature-rich autopilot. I love it.

However, compared to the old mechanic, (which i THINK was called spaceplane hold?), the autopilot seems to have a very difficult time keeping my aircraft from bouncing up and down through pitch. It can't seem to stabilize, until i've gone through the meticulous process of alot of limiting authority, on all pitch-active control surfaces, and even any SAS modules too.
 

Would it be possible to add some sort of tweakable factor within autopilot, that would determine some sort of aggressiveness, responsiveness or dampening of the autopilot?

[ansaman]

If you limit the authority of your control surfaces, you will achieve the correction you want. Some problems that people attribute to Mechjeb are actually caused by craft design.

Edited October 28, 2017 by ansaman

[Commissar]

14 hours ago, ansaman said:

If you limit the authority of your control surfaces, you will achieve the correction you want. Some problems that people attribute to Mechjeb are actually caused by craft design.

that's not a good solution. the authority of control surfaces needs to scale with speed. if the craft is unstable, that's another matter entirely

Edited October 29, 2017 by Commissar

[steve_v]

1 hour ago, Commissar said:

the authority of control surfaces needs to scale with speed.

More dynamic pressure than speed. Both FAR and Dynamic Deflection (currently unmaintained, probably just needs a recompile for 1.3.1), do this already.
Personally, I see this as out of scope for MechJeb...

[danielboro]

23 hours ago, lekkimsm2500 said:

Sarbian, love the work as usual.

And i have a suggestion. I've been fiddling about with build 747, haven't updated for quite a while previous of that, and now noticed the wonderfully feature-rich autopilot. I love it.

However, compared to the old mechanic, (which i THINK was called spaceplane hold?), the autopilot seems to have a very difficult time keeping my aircraft from bouncing up and down through pitch. It can't seem to stabilize, until i've gone through the meticulous process of alot of limiting authority, on all pitch-active control surfaces, and even any SAS modules too.
 

Would it be possible to add some sort of tweakable factor within autopilot, that would determine some sort of aggressiveness, responsiveness or dampening of the autopilot?

 

22 hours ago, ansaman said:

If you limit the authority of your control surfaces, you will achieve the correction you want. Some problems that people attribute to Mechjeb are actually caused by craft design.

some change in KSP made all PID`s in autopilots stop working
this oscillation can be seen in KOS, TCA, MJ and the unpatched RT(was fixed in the beta patch)

Edited October 29, 2017 by danielboro

[Geschosskopf]

I'd like a little MJ help from the audience

I'm having a bit of an annoyance with the "Limit Q to (value)" setting in Ascent Guidance.  If I have this checked, it bleeds over into all atmospheric flights even if Ascent Guidance is not running.  This is a bother because it throttles down jet engines so the planes never reach supersonic speeds.  The workaround is simple---just open Ascent Guidance and uncheck the "Limit Q" box that was still checked from the last rocket launch.

So here's the questions:

1.  Does this happen to anybody else?

2.  Is there some way to leave the "Limit Q" box checked and not have it bleed over?  Or is this just one of MJ's endearing little quirks?

Thanks.

[Mine_Turtle]

I am experiencing some odd behavior from MechJeb smart assist module. Could someone take a look, please?

 

[Gilph]

On ‎10‎/‎30‎/‎2017 at 11:23 AM, Geschosskopf said:

I'd like a little MJ help from the audience

I'm having a bit of an annoyance with the "Limit Q to (value)" setting in Ascent Guidance.  If I have this checked, it bleeds over into all atmospheric flights even if Ascent Guidance is not running.  This is a bother because it throttles down jet engines so the planes never reach supersonic speeds.  The workaround is simple---just open Ascent Guidance and uncheck the "Limit Q" box that was still checked from the last rocket launch.

So here's the questions:

1.  Does this happen to anybody else?

2.  Is there some way to leave the "Limit Q" box checked and not have it bleed over?  Or is this just one of MJ's endearing little quirks?

Thanks.

Q limit is also part of Utilities. When you see it happening, open the Utilities to see if it is enabled. If it is, just clik it off. This may be functionally the same as you describe above, but this may persist between modes.

Edited October 31, 2017 by Gilph

[Geschosskopf]

Thanks.

[KUBA71]

Cannot achieve automatic "Depoly landing gear" with MECHJEB landing guidance.

I found it on my career 1.3.1 and CKAN listed MECHJEB versions

now testing ...clean KSP1.3.1.1891 (WindowsPlayer x64) en-us install /with only mechjeb 2.6.1.0 #748 mod

same results.

 

2.6.1.0 #747 and #748 lands on picked target, "Deploy Parachutes" works,

but landing gear stays always retracted. (Kerbin, Mun, Dune... tried difernet ships, diferent landing gears)

 

Bug or I do something wrong? ... online manual is empty ...Help 

Link: http://wiki.mechjeb.com/index.php?title=Manual/Landing_Guidance

   

[softweir]

Might be worth trying again, then find the log and upload it somewhere and post a link to it, just in case that shows a cause.

[Synthesis]

I'm relieved to see that landing autopilot is broken for everyone else too--I tried to set up a landing on Minmus on the equator and laded probably about 1/4 of the moon's diameter away...on the equator. 

[Gorby1]

56 minutes ago, Synthesis said:

I'm relieved to see that landing autopilot is broken for everyone else too--I tried to set up a landing on Minmus on the equator and laded probably about 1/4 of the moon's diameter away...on the equator. 

It's working wonderfully for me, with two exceptions; the inclination burn does fine, the de-orbit burn does fine, but when using auto-warp after the de-orbit burn on the way to the braking burn the warp speed goes up to 5x and then immediately down to 1x, then back to 5x, over and over again until the the braking burn begins. I workaround this issue by always starting from an orbit in "low space" of the planet/moon, just below the boundary for "high space" (i.e. on the Mun I start from a 58km orbit). When starting from such an orbit the warping almost always works flawlessly during the descent.

5 hours ago, KUBA71 said:

Cannot achieve automatic "Depoly landing gear" with MECHJEB landing guidance.

I found it on my career 1.3.1 and CKAN listed MECHJEB versions

now testing ...clean KSP1.3.1.1891 (WindowsPlayer x64) en-us install /with only mechjeb 2.6.1.0 #748 mod

same results.

 

2.6.1.0 #747 and #748 lands on picked target, "Deploy Parachutes" works,

but landing gear stays always retracted. (Kerbin, Mun, Dune... tried difernet ships, diferent landing gears)

 

Bug or I do something wrong? ... online manual is empty ...Help 

Link: http://wiki.mechjeb.com/index.php?title=Manual/Landing_Guidance

   

I have this issue as well, in versions of MJ I used with KSP 1.2.x it worked fine. My workaround is pushing 'G' on my keyboard during the 500m vertical drop  sorry, my dad raised a smartass

[Gilph]

6 hours ago, KUBA71 said:

Cannot achieve automatic "Depoly landing gear" with MECHJEB landing guidance.

I found it on my career 1.3.1 and CKAN listed MECHJEB versions

now testing ...clean KSP1.3.1.1891 (WindowsPlayer x64) en-us install /with only mechjeb 2.6.1.0 #748 mod

same results.

 

2.6.1.0 #747 and #748 lands on picked target, "Deploy Parachutes" works,

but landing gear stays always retracted. (Kerbin, Mun, Dune... tried difernet ships, diferent landing gears)

 

Bug or I do something wrong? ... online manual is empty ...Help 

Link: http://wiki.mechjeb.com/index.php?title=Manual/Landing_Guidance

   

I have almost never had landing gear work. If my craft uses the landing gear 1 (the smaller one), directly attached to a center part, it seems to work fine.

I design many of my landers to have fuel tanks surrounding a center tank, and I put the landing gear on these outer tanks for a wider stance and more stability.  By that point, I usually need the bigger ones (lg 2?). In this configuration, deploy landing gear has never worked, even back to 1.0 days. Not sure if it's the second layer of tanks or the larger landing gear. My workaround is usually the same as @Gorby1, unless nature calls and I hit 'G' and trust to Mechjeb.