Flight Question Rotation attitude control whilst docked very slow

[Southwell]

Hey, I am sure I am not the only one who has come across this, I searched and couldnt find a thread on it. I have found when I have two vehicles docked my rcs control of the two ships sucks, I found this to happen in AMSO and the Donovan Interplanetary addon as they are the only ones I am using so far. Is there a remedy to this??

Thanks

Ben

 

[garyw]

Of course it does, you have a huge mass attached and the RCS rates take this into account. You'll also find that if you don't know where the Centre-of-Gravity is a simple RCS manoeuvre will put you all over the place.

 

[Southwell]

yes I undesrstand that, but shouldnt orbiter be able to consider the two vehicles one body or something along those lines? Not even IMFD or LunarTransfer MFD can orientate the stack for any burns. How do I fix this??

 

[martins]

That isn't really the responsibility of orbiter. Orbiter provides the physics, you provide the logic. Write an attitude autopilot that hooks up the thruster controls for the individual RCS thrusters of all the vessels in your stack and engages them to provide the required rate change. Input would be the total PMI of the stack and the thruster positions in a common frame.

Note that for the most general case the inertia tensor wouldn't be diagonal, but you may be able to ignore this. Also, the RCS positions usually wouldn't be balanced, so you will get a parasite linear thrust component.

 

[Southwell]

mmm ok thanks, I am not at a level where I can write my own code, but I am sure someone has allready done this for the addons. I will look there.

Thanks

Ben

 

[Izack]

There is, but it's buggy and unhelpful.
[ame="http://www.orbithangar.com/searchid.php?ID=3819"]Vessel Stack[/ame]

It's not entirely relevant, but there is a DLL for the [ame="http://www.orbithangar.com/searchid.php?ID=3865"]NERVA 2[/ame] interplanetary engine that will automatically gimbal main thrust to compensate for COG shifts. It was posted here a while back for OFMM.