Difference between revisions of "Small Inline Reaction Wheel"

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{{Partbox
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{{:Inline Reaction Wheel/Box}}
|Name=S.A.S. Module
 
|Role=Attitude Autopilot
 
|Class=SASModule
 
|File=S.A.S. Module.jpg
 
|Costs=2300
 
|Mass=0.8
 
|More=
 
{{PB-more|max. Torque|10 N*m}}
 
{{PB-more|Ki|1.0}}
 
{{PB-more|Kp|3.0}}
 
{{PB-more|Kd|5.0}}
 
|since=v0.7.3
 
|cfg=Parts/sasModule/part.cfg
 
}}
 
  
The '''S.A.S. Module''' is a toggleable module that acts as a sort of Autopilot to stabilize and help keep a rocket on course.
 
  
== Description ==
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The '''Small Inline Reaction Wheel''' (previously named '''Inline Reaction Wheel''') is a toggleable [[reaction wheel]] that provides torque to a craft. Extra torque means that the player's spaceship will rotate faster when ordered to, resulting in a more nimble feel to the craft. The Inline Reaction Wheel is the 'Tiny' size reaction wheel.  
{{Quote|SAS: Stability Augmentation System, Spin Auto-Stabilizer, Sickness Avoidance Solution. Whatever you choose to call it, it makes the ship stop spinning around.|O.M.B. Demolition Enterprises}}
 
  
 
== Usage ==
 
== Usage ==
S.A.S. modules do not have to be placed anywhere in particular to function, however it will cease to function if jettisoned. They appear to function on a stability:mass ratio and the effect can be enhanced by adding additional S.A.S. modules. Often a single S.A.S. module isn't enough. It is worth considering that they do add to the mass of your ship; if you require a lot of S.A.S. modules to get a large ship off the ground, you should think about distributing them such that they are dropped along with your earlier stages.
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{{quote|The placement does matter for [[reaction wheel]]s. Generally speaking they can cause some problems if placed far from the [[center of mass]]. Imagine you are grabbing that point and rotating it. That is what the reaction wheels will try to do. You'll get offcenter rotation anywhere other then near the [[Center of mass|COM]].|[http://forum.kerbalspaceprogram.com/entries/740-Updated-Information-on-SAS-in-0-21-1#comment_4254 comment] by C7, in his blog entry “[http://forum.kerbalspaceprogram.com/entries/740-Updated-Information-on-SAS-in-0-21-1 Updated Information on SAS in 0.21.1]”}}
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However, this is not actually correct with rigid spacecraft. A reaction wheel should provide the same torque regardless of placement. However, off-center reaction wheels will cause very long vehicles, especially with docking ports, to bend, which can cause instability.
  
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== Product description ==
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{{Quote|The inline reaction wheel system uses a series of spinning discs that are going "Very Fast", to generate the torque necessary to control a spacecraft without wasting any propellant. Please do not attempt to service this device while it is running.|manufacturer=SEC}}
  
==Theory==
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== Trivia ==
The S.A.S. modules use a P.I.D. system, which stands for “Proportional, Integral, Derivative”.
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* The small inline reaction wheel seems to resemble HAL 9000 from the 1968 movie ''2001: A Space Odyssey''.
* ''Proportional'' means the S.A.S. module applies a turning-force that is proportional to the displacement from the "target" orientation. In other words, the further off-line the ship, the harder the module tries to correct it.
 
*''Derivative'' means the S.A.S. module takes the rate-of-turn of the ship in to account, and tries to apply a force against the turn. So the faster the ship is pitching, yawing, or rolling, the harder the S.A.S. module tries to stop the turn. This is supposed to dampen the action of the S.A.S module, preventing overshoot, as well as dampening any fast turn or roll.
 
* ''Integral'' means the S.A.S. module increases the corrective force the longer the ship is off-target. So if the ship is constantly "not-quite" on target, the S.A.S. module will ramp up the force used to correct the ship's orientation.
 
 
 
The S.A.S module found within the command module itself uses only PD, with no I.
 
The reason for overshoot is that the PID system is not well-tuned yet. The "I" and "P" factors are a bit too powerful, the "D" factor (which dampens movements) is a bit too weak.
 
 
 
[[Advanced S.A.S. Module|Advanced S.A.S.]] does not produce torque itself, it uses controllable components instead.
 
  
 
== Changes ==
 
== Changes ==
{{see also|Version History}}
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;[[0.90]]
'''v0.11.0'''
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* No longer has any SAS functionality - only provides torque
* ''(undocumented)'' SAS now use angular momentum instead or angular velocity - takes into account inertia momentum of the ship [http://kerbalspaceprogram.com/forum/index.php?topic=2905.msg31614#msg31614 ]
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;[[0.25]]
'''v0.9'''
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* Renamed “Inline Reaction Wheel” into “Small Inline Reaction Wheel”
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* Resized model and [[radial size]] from small to tiny
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* Mass decreased from 0.12 to 0.05
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* Torque decreased from 8 to 5
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* Required electricity decreased from 24.0/min to 15.0/min
 +
;[[0.24]]
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* Mass decreased from 0.3 to 0.12
 +
* Torque decreased from 20 to 8
 +
;[[0.21.1]]
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* Increased torque (3 → 20)
 +
* Mass decreased from 0.5 to 0.3
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;[[0.21]]
 +
* Renamed from “S.A.S Module” into “Inline Reaction Wheel”
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* Mass increased from 0.07 to 0.5
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* Costs electric charge
 +
;[[0.18]]
 +
* New model and texture
 +
* (Undocumented) Mass reduced from 0.8 to 0.07, cost reduced from 2300 to 600
 +
* (Undocumented) Torque increased from 10 to 20, Ki/Kp/Kd changed from 1.0 / 3.0 / 5.0 to 0.0 / 5.0 / 3.5
 +
;[[0.11]]
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* ''(undocumented)'' SAS now use angular momentum instead of angular velocity - takes into account inertia momentum of the ship [http://forum.kerbalspaceprogram.com/index.php?topic=2905.msg31614#msg31614 ]
 +
;[[0.9]]
 
* ''(undocumented)'' Tweaked Kd, Ki and Kp parameters
 
* ''(undocumented)'' Tweaked Kd, Ki and Kp parameters
'''v0.8.5'''
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;[[0.8.5]]
 
* Exposed Kd, Ki and Kp parameters for tuning the SAS module
 
* Exposed Kd, Ki and Kp parameters for tuning the SAS module
'''v0.8'''
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;[[0.8]]
* SAS toggle with 'T' key
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* SAS toggle with {{Key press|T}} key
'''v0.7.3'''
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;[[0.7.3]]
 
* Initial Release
 
* Initial Release
  
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== Notes ==
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<references />
  
 
{{Parts}}
 
{{Parts}}
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[[Category: Reaction wheels]]

Revision as of 00:36, 12 July 2021

Inline Reaction Wheel/Box


The Small Inline Reaction Wheel (previously named Inline Reaction Wheel) is a toggleable reaction wheel that provides torque to a craft. Extra torque means that the player's spaceship will rotate faster when ordered to, resulting in a more nimble feel to the craft. The Inline Reaction Wheel is the 'Tiny' size reaction wheel.

Usage

The placement does matter for reaction wheels. Generally speaking they can cause some problems if placed far from the center of mass. Imagine you are grabbing that point and rotating it. That is what the reaction wheels will try to do. You'll get offcenter rotation anywhere other then near the COM.

comment by C7, in his blog entry “Updated Information on SAS in 0.21.1

However, this is not actually correct with rigid spacecraft. A reaction wheel should provide the same torque regardless of placement. However, off-center reaction wheels will cause very long vehicles, especially with docking ports, to bend, which can cause instability.

Product description

The inline reaction wheel system uses a series of spinning discs that are going "Very Fast", to generate the torque necessary to control a spacecraft without wasting any propellant. Please do not attempt to service this device while it is running.

STEADLER Engineering Corps

Trivia

  • The small inline reaction wheel seems to resemble HAL 9000 from the 1968 movie 2001: A Space Odyssey.

Changes

0.90
  • No longer has any SAS functionality - only provides torque
0.25
  • Renamed “Inline Reaction Wheel” into “Small Inline Reaction Wheel”
  • Resized model and radial size from small to tiny
  • Mass decreased from 0.12 to 0.05
  • Torque decreased from 8 to 5
  • Required electricity decreased from 24.0/min to 15.0/min
0.24
  • Mass decreased from 0.3 to 0.12
  • Torque decreased from 20 to 8
0.21.1
  • Increased torque (3 → 20)
  • Mass decreased from 0.5 to 0.3
0.21
  • Renamed from “S.A.S Module” into “Inline Reaction Wheel”
  • Mass increased from 0.07 to 0.5
  • Costs electric charge
0.18
  • New model and texture
  • (Undocumented) Mass reduced from 0.8 to 0.07, cost reduced from 2300 to 600
  • (Undocumented) Torque increased from 10 to 20, Ki/Kp/Kd changed from 1.0 / 3.0 / 5.0 to 0.0 / 5.0 / 3.5
0.11
  • (undocumented) SAS now use angular momentum instead of angular velocity - takes into account inertia momentum of the ship [1]
0.9
  • (undocumented) Tweaked Kd, Ki and Kp parameters
0.8.5
  • Exposed Kd, Ki and Kp parameters for tuning the SAS module
0.8
  • SAS toggle with T key
0.7.3
  • Initial Release

Notes