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Seppe87

Uncontrollable spinning

Question

Hi all,

I'm an avid and fairly experienced KSP-player. I've run into some issues that I can't seem to be able to solve.

During docking it often happens that my RCS thrusters start firing uncontrollably in 1 certain direction. I can't be absolutely certain but it seems to be in pitch. I can't be certain because my control indicators show no input whatsoever. I'm not touching my keyboard or mouse yet my RCS is flipping my satellites like crazy. When I turn off RCS and bring it back on they are firing again. When I switch to my station that I want to dock with and switch back, the RCS will still be thrusting (no matter if I disabled them during the switch or not). The only way to get control back of my craft is by going into the tracking station, finding the satellite/probe/whatever and getting back to it. You can imagine this has gone wrong on numerous occasions since this issue usually happens during docking. (Yes, that means big booms, reloading previous saves and starting all over again. My neighbors asked me who I was fighting with so much)

This happens nearly every time I dock and seems to increase in frequency as my station gets bigger (might be in my head though). It makes no difference if my SAS is turned on or off and does not seem to affect my reaction wheels.

However, to add to the mystery, sometimes this random rotation happens during other stages of a mission but then this IS visible in the control indicators AND influences my reaction wheels as well. Here as well the only option is to go to the tracking station and getting back to the craft. 

 

I have no clue what's happening, I can't find any obvious errors in the console and don't have any outdated I/O-devices on my PC.

I'm runnning 1.4.5, my installed mods are
- Chatterer
- Blackheart Stickers
- Environmental Visual Enhancements
- Firespitter
_ IDFlags
- Kerbal Engineer 
- Kerbal Joint Reinforcement
- Tweak Scale
- Docking Port Alignment Indicator
- Planet Shine
- SCANsat
- Scatterer
- Surface Lights
- Kerbal Alarm Clock

 

Any assistance is greatly appreciated. Furthermore, an image says more than a thousand words, so here are over 300000 words: 

 

 

By the way, I did some further testing. Things seem to go a lot better if I zoom in on my craft and I don't see my station. This means docking fully based on the DPAI. Not ideal but a valid workaround. However you can imagine I'd like to actually see what I'm docking with, so if there are any ideas I'd love to hear them.

Thanks!

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I have never experienced that in 1.4.5, So I don't know what to say.:mellow:

I also am in 1.5.1 so I probably won't have that problem.

Edited by BlueVapor1234

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Sound like you have some trim set some where, maybe.

Try hitting Ctrl-X to reset your trim. 

 

If that doesn't help, and I'm thinking it might not, but resetting your trim is the easiest first step....

Try docking from IVA, with the DPAI up.  It takes a bit of practice, but is by far my favorite way to dock manually.   Not only is it fun, but it might relieve the issue.    Won't help for probes though.   I have no idea why I think this might help, but it might help diagnose the issue, but I don't know how.....  LOL. 

 

The symptoms you describe are usually trim related, but how you are describing them makes me wonder....

 

 

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2 hours ago, Gargamel said:

Sound like you have some trim set some where, maybe.

Try hitting Ctrl-X to reset your trim. 

 

If that doesn't help, and I'm thinking it might not, but resetting your trim is the easiest first step....

Try docking from IVA, with the DPAI up.  It takes a bit of practice, but is by far my favorite way to dock manually.   Not only is it fun, but it might relieve the issue.    Won't help for probes though.   I have no idea why I think this might help, but it might help diagnose the issue, but I don't know how.....  LOL. 

 

The symptoms you describe are usually trim related, but how you are describing them makes me wonder....

 

 

I never work with trim on spacecraft since mine are [snip] symmetrical. But trim has passed my mind before as well but unfortunately killing any possible trim did nothing. 

Docking from IVA with DPAI is indeed very fun and is usually my preferred choice. However the majority of my space station are modules (thermal, electricity, fuel, science, ...) that are controlled by a probe. So IVA is a no-go. 

Most of the mods I have are not 1.5.1 compatible yet as far as I know, so I prefer to stay in 1.4.5 just a bit longer. :/

Edited by Snark
Redacted by moderator

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2 hours ago, Seppe87 said:

I never work with trim on spacecraft since mine are [snip] symmetrical. But trim has passed my mind before as well but unfortunately killing any possible trim did nothing.

   Trim can be accidentally applied, as we have found in these forums from time to time, but since you nulled all the trim, that's been ruled out. 

I have occasionally encountered something similar, but only when using the MJ autoland feature.  My only recourse is to manually turn off all the thrusters.  As you are not using MJ, this is not the case, and turning off your RCS will completely defeat the purpose of what you are trying. 

Does it ever happen when you are not within phsyics range of another vessel?  Did you jump over to the station and enable SAS to get the station to hold still?    If you let the craft alone, does it ever assume a specific orientation, or does it induce an accelerating spin?

 

Edited by Gargamel

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17 hours ago, Gargamel said:

   Trim can be accidentally applied, as we have found in these forums from time to time, but since you nulled all the trim, that's been ruled out. 

I have occasionally encountered something similar, but only when using the MJ autoland feature.  My only recourse is to manually turn off all the thrusters.  As you are not using MJ, this is not the case, and turning off your RCS will completely defeat the purpose of what you are trying. 

Does it ever happen when you are not within phsyics range of another vessel?  Did you jump over to the station and enable SAS to get the station to hold still?    If you let the craft alone, does it ever assume a specific orientation, or does it induce an accelerating spin?

 

As far as I can remember I only encounter the problem within physics range of other crafts. 
I often timewarp until I'm about 100m way. I never overshoot though and I won't go faster than x2 or maybe x5 in the last kilometer or so. But I doubt that has anything to do with it since the erratic behavior just suddenly pops up in the middle of a maneuver. The craft does not assume a specific orientation, if I wouldn't intervene it would just spin faster and faster until internal stresses would break it apart (although I don't think KSP calculates such internal stresses, but anyway....). So to describe the full scenario:

  • I launch 
  • I get to space 
  • circularize in such a way that I get an encounter with my target
  • warp loosely until I'm at 5km
  • warp at max x5 until I'm at 1km, max x2 until 200m
  • open DPAI
  • select docking port I want to control from
  • select docking port I want to target
  • start RCS-puffing my way towards the craft but before I can reach it...
  • the craft starts pitching at its max pitch rate
  • I disable RCS
  • go to Tracking Station
  • select my probe and go back to it
  • orient my craft again and continue docking

This goes on for a while until I finally dock. As mentioned this issue does not occur when I'm all the way zoomed in on my probe.

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5 hours ago, Seppe87 said:

As mentioned this issue does not occur when I'm all the way zoomed in on my probe.

That's just weird..... 

I got nothing though.... anybody? @4x4cheesecake?

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3 hours ago, Gargamel said:

That's just weird..... 

I got nothing though.... anybody? @4x4cheesecake? 

Yep, it is weird.

The only thing I can contribute right now is: It doesn't look like RCS fires in pitch direction but dorsal, which is by default bound to the 'K' key. Just to be sure, you can switch to docking mode (button to he right of the pitch indicator)  and the indicator for the 'Up' direction should move.

Anyway, I cannot think of a reasonable explanation what's causes this issue. Of course, docking two vessels together will indicate some forces which usually fires the RCS for a brief moment but that's not waht's happening here. Also, you didn't accidentally acitvated the 'Control by throttle' feature since the throttle stays at 0 (and AFAIK this would fire the RCS in 'forward' direction).

Well, it doesn't make any sense to me that this issue does not appear when zoomed in (except for: you're near-sighted and lean on your keyboad while the camera is not zoomed in, which accidentally hits the K-key :P ) since the camera position does not have any influence on the control inputs.

Thanks for pinging me @Gargamel, it's an interesting issue but unfortunately I have no ideas for a solution right now :/

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Do you happen to have a joystick plugged into your computer? We've seen often that causing problems like this.

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When you are docking, is the RCS aligned with the CoM and did you have SAS on?

 

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It's almost certainly not this, but because we're out of ideas, maybe it's a keybinding issue?

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16 hours ago, 4x4cheesecake said:

Yep, it is weird.

The only thing I can contribute right now is: It doesn't look like RCS fires in pitch direction but dorsal, which is by default bound to the 'K' key. Just to be sure, you can switch to docking mode (button to he right of the pitch indicator)  and the indicator for the 'Up' direction should move.

[...]

Well, it doesn't make any sense to me that this issue does not appear when zoomed in (except for: you're near-sighted and lean on your keyboad while the camera is not zoomed in, which accidentally hits the K-key :P ) since the camera position does not have any influence on the control inputs.

You're totally right, the NavBall clearly indicates a yawing motion. Can't believe I missed that :D. Although I set it to [W]. Next time it happens I'll check my docking mode to see if that registers any input or if it changes anything.
And I'm not near-sighted so I'm not accidentally leaning on my keyboard. 
The lack of problems when zoomed in made me think that it had something to do with visible part count (since my station has quite a lot of parts) but I can't figure out a connection between high part count and control input.

16 hours ago, 5thHorseman said:

Do you happen to have a joystick plugged into your computer? We've seen often that causing problems like this.

I always have a PS3 controller plugged in for my Rocket League games. It's fairly new so I can't imagine this being a problem but I'll make sure to unplug it next time I play and start messing about around my station and see what happens. 

12 hours ago, Xd the great said:

When you are docking, is the RCS aligned with the CoM and did you have SAS on?

My constructions are fairly symmetrical but not in such a way that my CoM stays in the same place when burning reaction mass. So I place 2 sets of RCS thrusters (so 8, with a maximum momentum arm) on every dockable craft where I can't guarantee a static CoM. And I always dock with SAS on since I often dock parts that need to be aligned very meticulously (such as external propulsion modules)

3 hours ago, Ultimate Steve said:

It's almost certainly not this, but because we're out of ideas, maybe it's a keybinding issue?

Maybe? I didn't like the standard configuration so I reconfigured a lot of the controls... If all else fails I can try to revert them to the original configuration although I'll need to learn how to play all over again :D

I'll let you know how it all plays out but real life has my calendar filled for the coming days so it might take a while :P

 

Thanks a lot for your valuable input people!!! Appreciate it a lot!

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6 hours ago, Seppe87 said:

The lack of problems when zoomed in made me think that it had something to do with visible part count (since my station has quite a lot of parts) but I can't figure out a connection between high part count and control input.

That's actually a good point I haven't noticed so far: You're ingame time is displayed yellow permanently and IIRC, that indicates a mismatch of physics frames and visual frames. Well, the physics are calculated for everything within 25km, it doesn't matter if the parts are visible or not but since it definitly incluences your game, you can try to increase the 'Max Physics Delta-Time per Frame' in the game settings. This will reduce the CPU load and may even help with your issue.

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Ive  had  this  problem  with  my  wireless  keyboard  and  being  to  far  away  from  the  receiver

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13 hours ago, putnamto said:

Ive  had  this  problem  with  my  wireless  keyboard  and  being  to  far  away  from  the  receiver

It  might  be  something  that  your  computer  is  inputing  without  your  keyboard.  Try  keeping  your  keyboard  closer.

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On 11/9/2018 at 6:15 AM, 4x4cheesecake said:

you can try to increase the 'Max Physics Delta-Time per Frame' in the game settings

Looks like this did the job. My gametime was still moving slow as a snail but no more random RCS thrusting.

Thank you all for your help

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