MPS development

[GLS]

Just creating a corner for MPS related stuff...

 

[GLS]

I'm still alive!!! :lol: Having some problems cooking the position of some valves on shutdown (must be able to shutdown an engine if it is at 109 or at 65...), but on the good side I think ignition is done!:speakcool:
Still have to do .scn save, EIU data side, don't think I'll be doing the purge seqs now...
Now I have to go... I'll have more in a couple of days.

 

[GLS]

Finally I've managed to complete a working version... it's far from perfect but it's a begining. Now I need someone to joint my code with the rest. Who want's the files?

Also, does anyone have any docs with the rules/valve position seq/whatever on ignition and shutdown??? (it's all open loop so there must be some rules) I have some charts with the position of the valves on ignition and shutdown, but for a shutdown during ignition I don't know what the vlvs do.

And about the MPS Power switches, do I call the panel to know what the switch is doing, or the switch calls me???

 

[Urwumpe]

Finally I've managed to complete a working version... it's far from perfect but it's a begining. Now I need someone to joint my code with the rest. Who want's the files?

Unless somebody else shouts louder, I think I should be your responsible maintainer.

Also, does anyone have any docs with the rules/valve position seq/whatever on ignition and shutdown??? (it's all open loop so there must be some rules) I have some charts with the position of the valves on ignition and shutdown, but for a shutdown during ignition I don't know what the vlvs do.

I have one such file, with many plots containing the pressures and flows inside the SSME. Do you want a small series of pdfs about the SSME by mail?

And about the MPS Power switches, do I call the panel to know what the switch is doing, or the switch calls me???

I created a way to decouple panels and subsystems - called "discrete signals" (discsignals).

The basic idea behind is: The subsystem has a input port (DiscInPort) which connects to the switch over one line of a "DiscreteBundle" object. The switch changes the voltage of the line by it's DiscOutPort, this way, we can use the Discrete signals also for analog signals - for example the analog MPS parameters for the MEDS and the primary C&W system.

Any questions?

 

[GLS]

Yes, I'll mantain it! But I need someone to put the mps files in the project, and then use the fucts in the GPCs... Then as I update the files I'll just send someone the updated files to replace them in the SVN. (for now internet access is a little... less than perfect...)
And about the switches, I'll study the discsignals!

Also one thing I keep forgetting to ask: Who creates the ET?

 

[Urwumpe]

Which part of the ET? The mesh is currently by DaveS, the code of the ET was not really touched yet.

 

[GLS]

So, I get the PROPELLANT_HANDLE on the constructor...
The .pdf file, is it on the web? If not, I can get up to 10Mb by e-mail... I'll PM you the address...

 

[Urwumpe]

So, I get the PROPELLANT_HANDLE on the constructor...
The .pdf file, is it on the web? If not, I can get up to 10Mb by e-mail... I'll PM you the address...

http://www.enginehistory.org/ssme.htm

Thats the same files I have, in a new location.

 

[GLS]

I have those... Thanks anyway!!! I also have one from Boeing, nice pics but not alot of info... and a bunch from ntrs...
I'm really starting to believe that we're going to have to kidnap a NASA employee to learn more about the shuttle....:titanic:

 

[DaveS]

I have those... Thanks anyway!!! I also have one from Boeing, nice pics but not alot of info... and a bunch from ntrs...
I'm really starting to believe that we're going to have to kidnap a NASA employee to learn more about the shuttle....:titanic:

I would suggest a USA employee since they're the ones who process the flight hardware at KSC. NASA only provides management and oversight.

 

[Urwumpe]

I would suggest a USA employee since they're the ones who process the flight hardware at KSC. NASA only provides management and oversight.

A DVD with the HAL/FC source code of the latest software in the Shuttle would be enough for me, many hardware problems are plain physics.

 

[GLS]

:feedback:
Currently, I'm *mentally designing* a valve class to have a more or less realistic valve operation. I'm thinking in having a basic class and them derive a bunch of vlv types. But I don't know how it's going to interface with the EPS or HYD, (or the piping, when I figure out how to make them, but that's a headache for another day!).:suicide:
I was wondering what you people think, because I want to make it so that it could also be used on OMS/RCS, etc...

 

[Urwumpe]

:feedback:
Currently, I'm *mentally designing* a valve class to have a more or less realistic valve operation. I'm thinking in having a basic class and them derive a bunch of vlv types. But I don't know how it's going to interface with the EPS or HYD, (or the piping, when I figure out how to make them, but that's a headache for another day!).:suicide:
I was wondering what you people think, because I want to make it so that it could also be used on OMS/RCS, etc...

Well, if you can write something which can solve the hydraulic equations, you are my hero. :lol:

I thought about using the math from the SSME document I have found, which would basically lead to describe the pipes, tanks & valves inside a engine similar to electrical circuits.


I found out that I can indeed solve the equations of the EPS even with very complex set ups - I just need maximal 4 passes (one for each power source).

I can keep you updated on the developments for the EPS in the EPS thread, but I am currently still busy with integrating your last code into Atlantis.

 

[GLS]

The flow stuff is just for the PMS....
About the doc: I don't know which engine type it refers to... I'd like more individual stuff and the types...

BTW: The FMOF engine nozzle is diferent from the other engines, it has no steam loop (3 curved lines on the outside of the nozzle), the line is strait. So mesh-making-people, you better put that way down in the bottom of your to-do list because it really doesn't matter a lot...:tumbleweed::lol:

I just found out I have a nice doc with redlines and stuff, but before I do the redlines I'd like to get the vlvs in a confortable position... (actually it has a lot about everything... I'll see if I can find it on the web)

 

[Kyle]

Only if my Grandpa was still living, he knew all about the shuttle as seeing he worked for it.

 

[GLS]

I just found out I have a nice doc with redlines and stuff, but before I do the redlines I'd like to get the vlvs in a confortable position... (actually it has a lot about everything... I'll see if I can find it on the web)

I'm talking about the Space Shuttle Operational Flight Rules.:blush: I can't find were I downloaded the one I have but there's a more recent one here. (mine is from 97 or 99...):chair: If anyone wants the old one...

EDIT: The old one is here http://www.fiddes.us/ just go down to "NASA Documents". There's also a LCC (lot's of GLS redlines).

 

[GLS]

:sos: Anyone has a list of the data in the VDT (Vehicle Data Table)??? I have around 20-25 (of 128 fields) taken from the docs posted above...

:sos:Also about the start enable/shutdown enable and start/shutdown cmds: my understanding is that they have to be sequential (ex. start enable, start). Any other cmd after the start enable will "reset" the enable... can anyone confirm this?

 

[Urwumpe]

:sos: Anyone has a list of the data in the VDT (Vehicle Data Table)??? I have around 20-25 (of 128 fields) taken from the docs posted above...

No, I have a complete set of downlist data for the RMS, and many variables recorded by the GNC sensors, but I doubt I can give you a full VDT.

:sos:Also about the start enable/shutdown enable and start/shutdown cmds: my understanding is that they have to be sequential (ex. start enable, start). Any other cmd after the start enable will "reset" the enable... can anyone confirm this?

No, does not make sense to me... If I see the diagram correctly, multiple GPCs issue the commands to the EIUs. So, there can be 3 commands of start enable, and 3 start commands from 4 GPCs reaching the three independent channels of the engine controller. (2 directly, 1 over a FIFO transmitting the first command and deadfacing the second).

All three commands in a frame get voted by the DCU A (or DCU B, if active).

There are 50 frames per second.

 

[GLS]

No, does not make sense to me... If I see the diagram correctly, multiple GPCs issue the commands to the EIUs. So, there can be 3 commands of start enable, and 3 start commands from 4 GPCs reaching the three independent channels of the engine controller. (2 directly, 1 over a FIFO transmitting the first command and deadfacing the second).

All three commands in a frame get voted by the DCU A (or DCU B, if active).

There are 50 frames per second.

When I say different cmds I mean different cmds (purge sequence 3, start, oxidizer dump...), not the different cmds signals from the GPCs...

About the VDT, I'm going to fill the blanks with *plausible* data...:lol:
I'll put a list in the svn soon.

 

[Urwumpe]

I have added two functions for you, to manipulate the SSME data in a safe and transparent way:

class SubsystemDirector
{
public:
    /**
     * @param usMPSNo numerical ID of the SSME
     * @param fThrust0 Vacuum thrust
     * @param fISP0 Vacuum ISP
     * @param fISP1 Sealevel ISP
     * @return false for failure, true for success
     */
    bool SetSSMEParams(unsigned short usMPSNo, double fThrust0, double fISP0, double fISP1);
    /**
     * @param usMPSNo numerical ID of the SSME
     * @param dir direction vector of the SSME force vector
     * @return false for failure, true for success
     */
    bool SetSSMEDir(unsigned short usMPSNo, const VECTOR3& dir);
};

With this, you can now change the engine parameters. You will not be able to directly access the ET, this will be done internally. For the future, the ET propellant resource will not get deleted after ET separation. Instead, we can use it for also representing the mass of the propellant stored inside the lines in the aft compartment - which will be important during the MPS dumps.

For the implementation of the ET and the propellant management system, just tell me how it would be best for you to get the data of the ET.