Docked ships and station start to wiggle until destroyed?

[CrashyMcCrashFace]

I had this problem and turning off all but one reaction wheel fixed it. For me just one active reaction wheel on the heaviest and/or most central part.

[strider3]

26 minutes ago, CrashyMcCrashFace said:

I had this problem and turning off all but one reaction wheel fixed it. For me just one active reaction wheel on the heaviest and/or most central part.

I agree, in theory, but when I'm docking much bigger (more mass) ships to a smaller station, and transferring fuel, etc., nothing seems to really work to avoid this other than getting it over with and undocking ASAP. This is my philosophy going forward, at any rate. I will build a bigger station, based on lessons learned, for future exploration beyond Duna. I will have to ask more questions about this and "rigid attachments" and "auto struts" and construction of, and piecing together of, such a station at a later date.

[blakemw]

On 4/29/2018 at 1:39 PM, Rauko said:

Regarding autostruts problem, is not a good idea to autostrut always to grandparent? I have the impression that "heaviest part" can change easily when docking, leading to woble and explosions, but grandpa is more dificult to change, and is equaly effective making the whole structure stronger. Am I wrong?

Grandparent is much safer because it's much more limited in its scope, but it's also less powerful - except when dealing with symmetrical placement, for some reason autostrut connects to the grandparent and ALL the grandparents "symmetry brothers", a simple example:

This is useful for creating large, rigid, stable structures. Importantly, unlike "root/heaviest part", which concentrates forces on one part, symmetry grandparent distributes forces. It's an incredibly powerful technique when used deliberately and it's almost always a good idea to try and make the core of a station a symmetry structure, as an example:

Because the station was built using symmetry, now when the Jumbo-64 fuel tank is set to "autostrut: grandparent part", it generates 4 autostruts, widely dispersing the forces over the station.

[Serenity]

5 hours ago, blakemw said:

Because the station was built using symmetry, now when the Jumbo-64 fuel tank is set to "autostrut: grandparent part", it generates 4 autostruts, widely dispersing the forces over the station.

Huh thats really interesting.

[Norcalplanner]

On 4/29/2018 at 10:38 PM, CrashyMcCrashFace said:

I had this problem and turning off all but one reaction wheel fixed it. For me just one active reaction wheel on the heaviest and/or most central part.

This.  Especially if the reaction wheels are far away from each other and/or rotated 90 degrees from the root part.  If there are reaction wheels in each of those large arms on the station, turn them all off and see if things improve.

[ArmoredLipid]

I have had this problem before. It can be completely solved by switching every reaction wheel on both the docked ship and the station, including built-in command module ones, to "pilot-only" mode. This is because stability-assist mode will accidentally increase minute wobbles while trying to correct them.

[strider3]

On ‎6‎/‎20‎/‎2018 at 10:31 PM, ArmoredLipid said:

I have had this problem before. It can be completely solved by switching every reaction wheel on both the docked ship and the station, including built-in command module ones, to "pilot-only" mode. This is because stability-assist mode will accidentally increase minute wobbles while trying to correct them.

What, exactly, does "pilot only" do?

Edited June 28, 2018 by strider3

[bewing]

2 hours ago, Victor3 said:

What, exactly, does "pilot only" do?

It makes it so that the SAS system is not allowed to use that reaction wheel. The reaction wheel only responds to WASDQE commands from the keyboard (ie. you, the "pilot").

[strider3]

17 hours ago, bewing said:

It makes it so that the SAS system is not allowed to use that reaction wheel. The reaction wheel only responds to WASDQE commands from the keyboard (ie. you, the "pilot").

OK, does this also mean that picking an orbital position ("Normal", "Prograde", etc.) on the Navball will not work with "pilot only" selected? (I'm guessing that's true).

Thanks, gang!

Edited June 29, 2018 by strider3

[bewing]

5 hours ago, Victor3 said:

OK, does this also mean that picking an orbital position ("Normal", "Prograde", etc.) on the Navball will not work with "pilot only" selected? (I'm guessing that's true).

Thanks, gang!

If you set every single reaction wheel to "pilot only" and turn off RCS and all your engines, then yes -- the SAS system would have nothing left to work with at that point to maintain your orientation.

 

[strider3]

On ‎6‎/‎29‎/‎2018 at 5:41 PM, bewing said:

If you set every single reaction wheel to "pilot only" and turn off RCS and all your engines, then yes -- the SAS system would have nothing left to work with at that point to maintain your orientation.

 

Thanks, brother.

I am building "Mobil1" refueling station in 350km orbit around Kerbin. Using the various suggestions...

I am using Grunf911's basic design for a refueling station.

I am using NearFuture Construction's "weldable" docking ports to attach tanks, hopefully a more solid connection.

I have 2 reaction wheels on the station, set as close to the central core as possible and, for now, I am setting them at 20% torque rather than "pilot only". We will see how that goes. The Cupola wheels are off and any docked ship's wheels will be turned off.

I am using auto-strut "grandparent" mode almost exclusively (except for parts attached to central core).

I am not using any "physical" struts or "rigid attachment".

I do have one question regarding reaction wheels. I did not invert the lower one on the station. Does that make any difference in how they work?

We will see if these things help with the "wobble of death" once I bring large ships to dock and refuel. Hopefully my experiment will help others having the issue?

 

Here's how Mobil1 looks, so far. Still have many tanks to attach...

As always...you people are AWESOME! Thank you very much for all your help and guidance.

[bewing]

7 hours ago, Victor3 said:

I do have one question regarding reaction wheels. I did not invert the lower one on the station. Does that make any difference in how they work?

Nope.