RCS rotational lockout and balanced translational movement....

[PanzerAce]

So....not sure where this should go, so I'll pop it here where the most people can see it and (hopefully) answer my questions. Two parter:

1) Is there a way either in game or in a config file to lock out the RCS from reacting to rotational commands? Building some larger parasite ships, and I've got more than enough torque to go around, but I either have to wait for it to be perfectly still before I activate RCS to do any translational movement to dock, or I have to burn simply absurd amounts of RCS fuel as SAS tries to hold it steady because the ships:

2) Have oddly located RCS thrusters. Nothing I can do about them (Using the MK2 expansion Hypersonic nose cone), and if I turn the front RCS thrust limiter down to the point that I can translate left/right without inducing a spin, I have FAR too little up/down thrust at the front to avoid flipping the ship. Is there a mod to dynamically control RCS strength, so that I don't have to worry about inducing rotation in a ship when I'm trying to translate it to dock?

[superstrijder15]

1) Mechjeb has got a setting for that, but I forgot where...

[PanzerAce]

orly? I don't remember that from the last time that I had MJ installed. I *personally* prefer doing everything by hand, but if MJ has the ability to lock the RCS out, I'll be installing it ASAP (well, once I'm not drunk and up waaaayyyyyy too late while I think about how to min/max a mining tug for my grand tour gigantor ship)..

[Gargamel]

Under attitude adjustment, you can tweak the amount of RCS burned.  I'm not completely familiar with all the settings (lots of scary numbers lol), but there's a big % bar you can adjust for the amount of thrust used.  For bigger ships, I raise the value to make them spin faster.   Setting this to a lower setting might help your problem.  There are a bunch of other RCS controls that I've played with over time to tweak ships that don't fly right.  

Also, another beautiful thing I found is the "show COM" button under attitude adjustment.  Puts a red dot where your COM is, and When I build planes, I'll mark (usually with an inline antenna) where my center of lift is, and adjust my COM to stay in the appropriate spot. 

And if you can manually dock the ship, then you know you can do it.   I'd just let MJ take control and dock it for you, save the hassle. 

[PanzerAce]

22 minutes ago, gargamel said:

Under attitude adjustment, you can tweak the amount of RCS burned.  I'm not completely familiar with all the settings (lots of scary numbers lol), but there's a big % bar you can adjust for the amount of thrust used.  For bigger ships, I raise the value to make them spin faster.   Setting this to a lower setting might help your problem.  There are a bunch of other RCS controls that I've played with over time to tweak ships that don't fly right.  

Also, another beautiful thing I found is the "show COM" button under attitude adjustment.  Puts a red dot where your COM is, and When I build planes, I'll mark (usually with an inline antenna) where my center of lift is, and adjust my COM to stay in the appropriate spot. 

And if you can manually dock the ship, then you know you can do it.   I'd just let MJ take control and dock it for you, save the hassle. 

The problem is that it's not a pure thrust adjustment that I need. Or rather, not a "Change the thrust and lock it". Translation without inducing rotation requires different thrust levels if I'm going up/down vs. left/right....

[Brainlord Mesomorph]

3 hours ago, PanzerAce said:

2) Have oddly located RCS thrusters. Nothing I can do about them

Well, I think there's your problem, right there, sir.

[_stilgar_]

3 hours ago, PanzerAce said:

Have oddly located RCS thrusters. Nothing I can do about them

Just press Caps Lock. You will get precise mode or whatever it's called. It will make sure your RCS will only do what you want it to do (translations without rotations and vice versa)

[superstrijder15]

I found it! Under smartRcs with mechjeb uncheck "use rcs for rotation" and then... well then it doesn't use rcs for rotation anymore

[Freshmeat]

My RCS switch usually just gets a lot of workout during docking maneuvers. I have it as the stick button on my translational joystick.

[superstrijder15]

I think the problem is that while he presses like "K" or something, the sas intantly tries te correct with rcs, effectively pressing "I" 

[Gargamel]

22 hours ago, PanzerAce said:

The problem is that it's not a pure thrust adjustment that I need. Or rather, not a "Change the thrust and lock it". Translation without inducing rotation requires different thrust levels if I'm going up/down vs. left/right....

The attitude adjustment changes overall/max speed I believe, that's at least I how see it and use it.   It may help alleviate some of the problem as it should limit the excess thrusters to cap the max force applied.   Maybe.  Read hthe mechjeb wikis and play with the settings.  I know it can do what you're asking. 

[bonyetty]

Docking mode (blue button bottom left hand side)locked to translation (space bar switches between rotation and translation with wasd) and using just puffs of the RCS works for me. 

[Val]

On 01/03/2016 at 0:07 PM, _stilgar_ said:

Just press Caps Lock. You will get precise mode or whatever it's called. It will make sure your RCS will only do what you want it to do (translations without rotations and vice versa)

This!

[Geschosskopf]

On 3/1/2016 at 1:51 AM, PanzerAce said:

1) Is there a way either in game or in a config file to lock out the RCS from reacting to rotational commands? Building some larger parasite ships, and I've got more than enough torque to go around, but I either have to wait for it to be perfectly still before I activate RCS to do any translational movement to dock, or I have to burn simply absurd amounts of RCS fuel as SAS tries to hold it steady because the ships:

I build my ships with beaucoup torque as well for rotation so I only turn RCS on (R key) when I need it for translation.  So, when docking, I rendzevous with the main engines and torque to stop on the side of the target where there docking port is, then rotate parallel with the docking axis using torque.  @NavyFish's Docking Alignment Indicator shows me when I'm lined up.  I have SAS on the whole time, of course, so the torque will then keep the ship at that orientation.  Then I turn on RCS and use it for translating to dock without ever rotating again.

Of course, this requires perfectly balanced RCS thrust to keep translation from introducing unwanted rotation, which is the subject of your next question.

On 3/1/2016 at 1:51 AM, PanzerAce said:

2) Have oddly located RCS thrusters. Nothing I can do about them (Using the MK2 expansion Hypersonic nose cone), and if I turn the front RCS thrust limiter down to the point that I can translate left/right without inducing a spin, I have FAR too little up/down thrust at the front to avoid flipping the ship. Is there a mod to dynamically control RCS strength, so that I don't have to worry about inducing rotation in a ship when I'm trying to translate it to dock?

In case you didn't know, you can right-click on the Mk2 Extension parts with builtj-in RCS and disable their thrusters completely.  You can also make doubly sure of them by setting their thrust limiter to zero, but disabling them entirely is really all you need.  So that takes care of that, and you can now just use regular RCS thrusters elsewhere on the ship, which means you can balance them properly.

In case you don't have it already, get @m4v's indefensible RCS Build Aid mod to make sure your RCS thrusters are balanced.  However, be sure to have this key on whichever CoM position you think will be the case when you're docking (full, average, or dry).  And you should really build the entire ship with RCS Build Aid showing the CoM markers so you can shape the entire thing so the CoM doesn't move much if at all regardless of fuel consumption.

If you're using Mk2 fuselage parts throughout, I recommend using the 5-way streamlined RCS thrusters from Mk2 Extension.  You only need a total of 4 of these mounted on the narrow edges of the fuselage (or in that same plane) to have complete and balanced 6-way translation.  However, sometimes you can't  locate a thruster where you want it, so get things as balanced as you can then add single 1-way thrusters (and tweak their thrust limiters as needed) to balance the 5-ways.

With this sort of set-up, you should be able to dock just fine without changing config files, tweaking MJ settings, or switching control modes.  In practice, even with RCS Build Aid, you'll probably still have a very slight thrust imbalance when docking (especially with larger ships) .  However, you've got monster torque and SAS on so that will correct rotation from short blips of RCS (although long, constant burns will throw it off a bit).  SAS will use a bit of RCS to help maintain orientation but not enough to worry about.

As mentioned by others, the stock game has a "fine control" setting for RCS which also provides SOME (but not much) RCS thrust balancing.  Access this with CAPS-LOCK, which turns the pitch/yaw/roll indicators in the lower left corner a light blue instead of their normal orange.  The balancing isn't very much so will only work if your thrusters are pretty close to being balanced already.  But the biggest problem with "fine control" is that it slaps a major thrust limitation on all your RCS thrusters, so they only produce about 1/2 or less of their normal thrust.  This makes it VERY time-consuming to dock big, heavy ships, and also makes them very slow to respond to RCS inputs, so you have to be careful not to overshoot or make the final approach to the docking port too fast

 

 

 

[PanzerAce]

On 3/1/2016 at 3:07 AM, _stilgar_ said:

Just press Caps Lock. You will get precise mode or whatever it's called. It will make sure your RCS will only do what you want it to do (translations without rotations and vice versa)

Nope. That just turns down the amount of thrust that an RCS thruster does. It doesn't lock SAS out from using them.

[_stilgar_]

53 minutes ago, PanzerAce said:

Nope. That just turns down the amount of thrust that an RCS thruster does. It doesn't lock SAS out from using them.

I was responding only about point 2, uneven rcs placement.