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

[El Sancho]

19 minutes ago, apholis said:

 

i did in sandbox i havent tried it in career yet, and you're right i didn't go to the pad when i did they were there, thanks for helping

My pleasure, apholis. We all try to help each other with minimal asshattery, which is a good part of what makes this such an awesome community. I've been playing KSP since 2014, IIRC, and there are still regions of both KSP and MechJeb which I haven't explored. The videos on YouTube are inspiring, though I have learned the hard way that just because Nikola Wiche can do something doesn't mean I can

 

Nota Bene: the above is NOT MY VIDEO, it is by Nikola Wiche, whose channel is linked above.

Edited September 5, 2018 by El Sancho
a veces lo barato sale caro

[vossiewulf]

On 9/4/2018 at 9:46 PM, El Sancho said:

If you're using version 801, I'd suggest you go back to version 800

801 had some experimental stuff going on with RCS. You should find that 800 works quite well.

Build 800 indeed fixed the problem, he landed a 50t or so lander about 10 feet from where I wanted him on Duna, right next to the big lander I put down manually. Thanks.

@sarbian, the current release version seems to have completely broken Landing Guidance, I would think that would merit a new release. Instead of starting with a target that's long of the final target and slowly burning retro until he's on the final target, he inefficiently burns well short of the final target and then keeps burning to move it prograde toward the final target... before losing control and drunkenly crashing. Note that I just tested this with the exact same ship starting from the exact same orbit, current release vs. v800, the latter worked perfectly.

[dlrk]

A couple quick things:

The wobbling when SMART ASS is used on a rocket with aerodynamic surfaces and FAR doesn't seem to be intrinsic to MJ and FAR being used together, since the aircraft autopilot works fine.

Other thing:

I think this might be an error on my part, but when I engage altitude hold in the aircraft autopilot, it aggressively pitches to hold the current altitude, regardless of what is set.

[JH4C]

10 hours ago, dlrk said:

I think this might be an error on my part, but when I engage altitude hold in the aircraft autopilot, it aggressively pitches to hold the current altitude, regardless of what is set.

There does seem to be a very small margin for error in establishing your aerodynamics for stable flight; I've spent ages moving parts a degree here, a pixel forwards or backwards there, and it'll ride like a bucking bronco until... Well, I wish I knew what I was doing that fixed it, because half the time it seems to me like I just cycle through various configurations and end up back where I started a few hours later, only to find that what didn't work before does now!

While I'd previously been okay with 801, this week I've been having real trouble with getting aircraft to reach and maintain high altitudes (10km and up, the higher the harder) using MJ. Sometimes I'll be able to get them up to 20km and cruise effortlessly at mach 2.5+, other times they'll only get as high as 18km or 19km, then they'll start slipping back down while maintaining a climbing attitude and they won't actually start climbing again until I've fallen to 15km, 12km, sometimes even 7km. I may try going back to 800, see if there's any difference.

[El Sancho]

 

(shrug)

KSP is a rocket simulator. It doesn't really simulate aircraft flight all that well.

[dlrk]

Sorry, I think my question was misunderstood. Aircraft flight works fine (particularly since I'm using FAR). The problem I'm having is that altitude hold holds the current altitude, not the altitude set in the box. Aerodynamics has nothing to do with that.

[JH4C]

Not had that; if I use the box to pick a height and it's within the flight envelope, then it gets to that height. If I pick the Vertical Speed hold, then it holds my current altitude or adopts the glide slope requested. I don't use FAR though.

[sarbian]

I guess I'll have to revert some of the landing AP recent changes. I'll try to find some time this week...

 

[dlrk]

@Sarbian

I didn't try the landing AP, just the aircraft AP. But thanks for looking into it!

[JH4C]

Hrm.

Well, I tried switching back to 800, and it's a case of picking the one which works closest to what I need, I think. 801 has landed me on the KSP runways perfectly, but one time turned hard left when I tried to put a plane onto Island 27 and I ended up landing up the bank instead. 800 also seems to handle the KSP runways okay, but ditched me in the sea 500 meters short of Island 27! Also regardless of which version I'm using, the speed shown in the navball is usually 3/4 of the approach speed I've selected. (Oh, and in the Landing AP, there's a typo "Break on landing" should be "Brake on landing".)

Regarding high-altitude work, I took exactly the same plane and ran it through identical manoeuvres, at least as far as I could. 800 took off more smoothly, and got up to the target altitude in a single run, and even held it (well, stayed within ±1km of it) but if I used Climb speed = 0 to hold altitude at unset points then the plane bucked like a bronco. 801 had to reach a higher speed before I took off, bucked instead of flying level at low levels, and still couldn't make it to the target altitude, but was much more predictable mid-flight.

My plane's basically a very long fueltank with wings, and if I didn't know better I'd say it was slopping back & forth and causing instability that way...

Oh, also spotted a potentially annoying quirk: if you mouse over the Autopilot settings box, even if it's not focused, flight control keyboard inputs are ignored. This is easily repeatable at any point, just put a plane on the runway and then move the cursor over the AP box, then try to activate roll/pitch/yaw control surfaces.

I've only used MJ in space for auto-circularisation of GravityTurn launches at this point, so cannot comment on how it works in other aspects. I do appreciate what El Sancho was saying, but atmospheric flight is a significant part of the game unless all you do is build stations in space or on airless worlds. I wish I could offer anything in the way of practical assistance to achieve that goal, but until then I'll offer reports on how the provided tools function in the hope of aiding in their improvement.

[dlrk]

My altitude hold issue turned out to be half user error and half confusing interface. The vertical speed limit box defaults to zero, and I didn't realize it needed to be set, I assumed that if it wasn't, it would climb at the current speed.

Would it be possible to take a look at improving the SMART A.S.S. handling of control surfaces though? The aircraft autopilot works great with FAR.

Edited September 10, 2018 by dlrk

[El Sancho]

12 hours ago, JH4C said:

(Oh, and in the Landing AP, there's a typo "Break on landing" should be "Brake on landing".)
 

Yes, I noticed that, but took it for KSP humor

Seriously, though, as an EFL teacher I'd politely remind you that not everyone here speaks English as their L1, and such mistakes are fairly common even among those who are native speakers.

I've been an expat for years now, and I stumble, bumble, and generally make a fool of myself in Castellano on a regular basis, so I can really understand.

[JH4C]

2 hours ago, El Sancho said:

I'd politely remind you that not everyone here speaks English as their L1

I'm well aware of that, which is why I indicated it as a typo. While the meaning is discernable to me as a native speaker, if English isn't your first language then deciphering homophones in a foreign language isn't going to be as easy. It benefits all parties if we work together to ensure accuracy.

[Fadly]

Most other autopilot function work pretty well. The only thing wrong is the altitude hold. I zeroed the problem to vertical speed hold setting. It simply lack proportional control. It lead to a series of overcompensation that cause the plane to lose control.

Edited September 11, 2018 by Fadly

[sarbian]

34 minutes ago, Fadly said:

Most other autopilot function work pretty well. The only thing wrong is the altitude hold. I zeroed the problem to vertical speed hold setting. It simply lack proportional control. It lead to a series of overcompensation that cause the plane to lose control.

Yeah, I know about this. A while ago someone submitted a patch that improved the airplane landing and changed a lot of the airplane code. The old code was actually better at handling the in flight control for all planes. The new code shakes some planes a lot...

If someone want to take some time to merge and or revert some of it I would welcome the help because I know I won't be able to look into it for a while. Those where the PR #937  and #938 (and #991 ?)

 

[kojot]

Dear Mechjeb specialists,

I am trying to script my spaceplane ascent with mechjeb using "Module Smart A.S.S." by changing pitch at some altitudes with "PROGRAM LOGIC - Wait for". However problem is everytime I declare new Smart A.S.S. with different pitch, mechjeb acts like it turn it off (Jesus take the wheel), no pitch control is present for a moment, and after new Smart A.S.S. kicks in, new pitch is present and vessel control is back. So nose is up, nose is down, and again nose is up.

Is there a better way for doing that to get smooth ascent with changing pitch at some altitudes? My ascent profile is more like positive parabola, not like rocket negative parabola.

Maybe adding some custom ascent profile for "ascent guidance" could be possible?

[Space_Coyote]

If is it possible how wold one go about say adding in landing sites for for both landing guidance and Space Plane Guidance.. After all we got now Wondering as well as the Desert launch sites..

 

I mean if it is disposable how would one be able to code this into the mech jeb unit programming/ Any ideas?

 

SPace_Coyote

[sarbian]

On 9/12/2018 at 4:58 AM, Space_Coyote said:

If is it possible how wold one go about say adding in landing sites for for both landing guidance and Space Plane Guidance.. After all we got now Wondering as well as the Desert launch sites..

Add and edit this file in your gamedata LandingSites.cfg

[El Sancho]

Exactly what Sarbian said, and here's a post I made back in July showing my own working version thereof.

(EDIT: Linking to exact post doesn't seem to be working, so I'll say instead, go back to page 72 and look for my post from July 23rd. It's about halfway down the page)

Obviously, it's a long file, there's a lot of scrolling down to be done...

Edited September 13, 2018 by El Sancho
a veces, la vida se complica...

[JH4C]

10 minutes ago, El Sancho said:

(EDIT: Linking to exact post doesn't seem to be working, so I'll say instead, go back to page 72 and look for my post from July 23rd. It's about halfway down the page)

Linking to replies works fine, you just need to be sure to click the top line to go to that specific post, rather than the OP of the thread.

For El Sancho's post, be sure to click where it says "El Sancho replied to a topic" and NOT the thread title.

[El Sancho]

 

Aaaah, so desu! Domo arigato, JH4C-san! I suppose that's what I get for posting so early, before caffeine.

In any case, the file I posted does work with MJ2 v800, both on Kerbin and with the two Minmus landing sites I have added. And it will allow use of the Aircraft Autolander at the Desert Runway, but please do note what I said about landings on Desert Runway 36 being problematic because of RUD Ridge. Perhaps that problem could be avoided with correct adjustment of the glideslope? I'd be interested to hear what others have found. I'd also be very interested to know what others think about that weirdness with the quotation marks around the body name.

I admit I'm not much on theoreticals, I'm more the trial and error sort, what an old boss of mine used to call "patch, fit, and fiddle", but I do get the job done. Eventually...

 

[maja]

@El Sancho or click that three conected dots in the upper right corner of a post and it will show you the link to the post. Works even on a mobile phone.

Edited September 13, 2018 by maja

[kojot]

On 9/12/2018 at 12:21 AM, kojot said:

Dear Mechjeb specialists,

I am trying to script my spaceplane ascent with mechjeb using "Module Smart A.S.S." by changing pitch at some altitudes with "PROGRAM LOGIC - Wait for". However problem is everytime I declare new Smart A.S.S. with different pitch, mechjeb acts like it turn it off (Jesus take the wheel), no pitch control is present for a moment, and after new Smart A.S.S. kicks in, new pitch is present and vessel control is back. So nose is up, nose is down, and again nose is up.

Is there a better way for doing that to get smooth ascent with changing pitch at some altitudes? My ascent profile is more like positive parabola, not like rocket negative parabola.

Maybe adding some custom ascent profile for "ascent guidance" could be possible?

Dear All, is it possible to script custom spaceplane ascent with mechjeb, or kOS is required?

[Cratzz]

Hi, im using the latest devbuild #801 on KSP v2.4.5 and TWR dosen't show correctly, anyone else? Seems kN is displayed alot lower than it is.

 

 

Edited September 15, 2018 by Cratzz

[sarbian]

On 9/13/2018 at 10:00 PM, kojot said:

Dear All, is it possible to script custom spaceplane ascent with mechjeb, or kOS is required?

I just did a quick test and it seems to work fine. Here is the script I used 

 

13 hours ago, Cratzz said:

Hi, im using the latest devbuild #801 on KSP v2.4.5 and TWR dosen't show correctly, anyone else? Seems kN is displayed alot lower than it is.

 

 

Your jet engine do not provide any trust in vacuum so the TWR is 0. The SLT (sea level) is correct and you set it to live so it is updated for your current altitude.