Why is everything dancing around everywhere?

[mellojoe]

So why is it that as soon as you turn on SAS, everything goes wobbly. It is as if the physics engine continually overcompensates. Sometimes I don't use it at all because the system is more stable without it. But as soon as I turn it on, any control surfaces I have are wobbling back and forth, RCS is shooting out everywhere ... even on a stable ship. It also seems to introduce a rotational element more often than not, too.

What causes this? Is there a solution?

Edited June 10, 2013 by mellojoe

[llamatoes]

The ASAS code is totally borked, I recommend you try to use ASAS minimally, and when you do, don't have RCS on at the same time.

[MajorNr01]

It is actually just the ASAS being badly configured. SAS in general works on the basis of a concept called PID-Controller. This controller can be configured with three parameters, generally called Ki, Kp and Kd. The game does not allow it, but you could actually change these parameters to suit any spacecraft and even large space stations. For myself I have made a plugin that adds a configurable ASAS and with it, I can easily trim the ASAS to perfectly control any craft. I think it is time to upload it to the Space Port...

[mellojoe]

Doing some searches shows that I'm not the only one with trouble with ASAS, so MajorNr01 it might be a VERY good idea if you have a fix. Or a tutorial to do the fix ourselves.

THANKS!

[Shrike42]

ASAS is overly aggressive, and can easily make a ship with a lot of control surfaces or vectoring engines shake.

To fix:

1. Don't have a ton of winglets on your rockets.

2. With planes, keep your control surfaces close to the middle.

3. Set up a custom action group on your lifter to toggle the gimballing of your droptank engines, steering only by the middle engine.

4. Make sure your RCS is symmetric around the center of mass; if possible, use only the linear RCS ports to help limit the number of places that ASAS will try to use to 'help'.