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Author Topic: ORDEAL Development Thread  (Read 36050 times)
Coussini
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« on: July 24, 2007, 09:33:56 AM »

I just want to know if the ORDEAL (Panel 13) is working with the FDAI. If i want to change the rate of the FDAI when i'm in lunar orbit, should i  change the switch to LUNAR only.



I wish, somewhere, a good person help me. Many times i send a post and i don't have any answer.  Worried
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Christophe
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« Reply #1 on: July 24, 2007, 10:27:27 AM »

Unfortunately not! The ordeal is not yet working.
For my own I think it should be a priority but...
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Swatch
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« Reply #2 on: July 24, 2007, 10:56:01 AM »

I agree, it should probably be a priority to get this working, but there isn't a lot of information on the ORDEAL, much less how it worked.  you may have to just wait but I'll see if I can come up with some psuedo-code to imitate what it is doing.
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My Project Apollo Work:
CM Visual
 -VC (~75% complete: texture work beginning again; mesh-78%; texture-70%)
Propulsion Particle Improvements (Focused on S1B right now, BETA 1.0 has been commited)
New Docking Method (~50% complete: research complete; coding partially completed, testing not underway)

Future Work:  (if it's here, it's deemed unnecessary to upcoming release)

Older Work:  (if it's here, it's fair game to whoever wants to improve)
EMS Implementation (committed: minor flaws, but groundwork is there, needs extensive testing)
EMS scrolls (committed: not refined, but usable)
SM Visual (committed: mesh-finished, texture-60%; possibly revisited in future)
J2 Texture (commited: room for improvement)
LRV (committed: mesh-finished, texture-90%; in future a ground up rebuild may be in order, but not on my plans)
Coussini
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« Reply #3 on: July 24, 2007, 12:17:19 PM »

Thanks for all.

If i have a unlimited acces to documentation i'm very hapy to search for that. Give me an full acces, and i'll search for you.  Yes

My oppinion is:

  • Button FDAI 1 and 2, to change the FDAI motion to stellar inertial or Orbital rate
  • Button EARTH and LUNAR is use on EARTH or MOON Orbit (logical)
  • Mode and slew are probably a precise adjust rate button (logical)
  • ALT SET is the altitude of the CSM in orbit to inform the FDAI and for the rate calculation
  • LIGHTING is probably a feature that not very crucial for this component

The ORDEAL drives the FDAI to make it display the spacecraft's attitude relative to the ground below.Conversely, if the spacecraft is to be flown in 'orb-rate,' keeping the same face towards the surface (to point cameras for example), it must rotate around one of its axes at a rate which matches the orbital period. Normally, the FDAI displays the spacecraft's attitude relative to the celestial sphere (i.e. it normally shows the inertial attitude) but the function of the ORDEAL is to provide the correct drive signal to rotate the FDAI at a rate which also matches the orbital period. With the ORDEAL, the FDAI will display attitudes relative to the surface below.

During the TLI burn, the guidance of the vehicle will be monitored using the FDAI in front of the Commander. The Saturn third stage will pitch up at a preprogrammed rate as the burn continues and the ORDEAL will drive the FDAI at a matching rate to compensate for the pitch motion. This will allow the FDAI to indicate a zero attitude all through the burn. Therefore, if necessary, the burn could be steered manually by Dave, just by keeping the FDAI and the associated rate needles zeroed.

The ORDEAL panel is very important. Do you imagine that astronaut have'nt any component like that when he want to take a photo from the moon. Probably, the CM have an automatic feature like PROGRADE to maintain the CSM in the proper ATTITUDE in orbit.
« Last Edit: July 24, 2007, 12:41:11 PM by Coussini » Logged

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Swatch
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« Reply #4 on: July 24, 2007, 01:09:27 PM »

yea, but I was referring more to how does the Ordeal control the craft...does it talk to the CMC directly? Does it control the RCS directly? etc....

It shouldn't be too hard to 'imitate' the behavior, but that's not necessarly historically accurate, and if we do something outside of the CMC that the CMC needs to know about then we run the risk of breaking something else in the code.
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My Project Apollo Work:
CM Visual
 -VC (~75% complete: texture work beginning again; mesh-78%; texture-70%)
Propulsion Particle Improvements (Focused on S1B right now, BETA 1.0 has been commited)
New Docking Method (~50% complete: research complete; coding partially completed, testing not underway)

Future Work:  (if it's here, it's deemed unnecessary to upcoming release)

Older Work:  (if it's here, it's fair game to whoever wants to improve)
EMS Implementation (committed: minor flaws, but groundwork is there, needs extensive testing)
EMS scrolls (committed: not refined, but usable)
SM Visual (committed: mesh-finished, texture-60%; possibly revisited in future)
J2 Texture (commited: room for improvement)
LRV (committed: mesh-finished, texture-90%; in future a ground up rebuild may be in order, but not on my plans)
Coussini
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« Reply #5 on: July 24, 2007, 01:34:52 PM »

Thanks Swatch.

yea, but I was referring more to how does the Ordeal control the craft...does it talk to the CMC directly? Does it control the RCS directly? etc....

.....

I said "Probably, the CM have an automatic feature like PROGRADE to maintain the CSM in the proper ATTITUDE in orbit". The ORDEAL is an Orbit Rate Display.... The purpose of this component is probably to fix display of the FDAI and not to perform a RCS action. The rate of the FDAI and that's it. The automatic feature that maintain the CSM in the proper Attitude is probably another thing, i supose.

If you check my answer before, you can read that the astronaut use it to insure that the TLI is on target like a CROSS sign in IMFD burn window. If the TLI is not on target, the astronaut do some manoeuvre using RCS to insure that is zero attitude.

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Tschachim
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« Reply #6 on: July 24, 2007, 02:39:07 PM »

It shouldn't be too hard to 'imitate' the behavior, but that's not necessarly historically accurate, and if we do something outside of the CMC that the CMC needs to know about then we run the risk of breaking something else in the code.

I also think the ORDEAL just drives the FDAIs directly.

For my own I think it should be a priority but...

OK, got it...  Wink

Cheers
Tschachim
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Swatch
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« Reply #7 on: July 24, 2007, 03:23:38 PM »

ok, but driving the FDAI doesn't tell the spacecraft what thrusters to fire in order to keep the orientation to the earth does it?
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My Project Apollo Work:
CM Visual
 -VC (~75% complete: texture work beginning again; mesh-78%; texture-70%)
Propulsion Particle Improvements (Focused on S1B right now, BETA 1.0 has been commited)
New Docking Method (~50% complete: research complete; coding partially completed, testing not underway)

Future Work:  (if it's here, it's deemed unnecessary to upcoming release)

Older Work:  (if it's here, it's fair game to whoever wants to improve)
EMS Implementation (committed: minor flaws, but groundwork is there, needs extensive testing)
EMS scrolls (committed: not refined, but usable)
SM Visual (committed: mesh-finished, texture-60%; possibly revisited in future)
J2 Texture (commited: room for improvement)
LRV (committed: mesh-finished, texture-90%; in future a ground up rebuild may be in order, but not on my plans)
Coussini
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« Reply #8 on: July 24, 2007, 03:39:03 PM »

yea, but I was referring more to how does the Ordeal control the craft...does it talk to the CMC directly? Does it control the RCS directly? etc....

It shouldn't be too hard to 'imitate' the behavior, but that's not necessarly historically accurate, and if we do something outside of the CMC that the CMC needs to know about then we run the risk of breaking something else in the code.

Swatch ,i found the following about the attitude control. Probably you know that. ATTITUDE CONTROL SUBSYSTEM (ACS) do that:



ALSO I FOUND THIS FROM THE LM, BUT IT'S PROBABLY THE SAME FOR THE CM:

ATTITUDE CONTROL

Desired attitude is calculated in the primary guidance computer and compared with the actual gimbal angles. If there is a difference between the actual and calculated angles, the inertial subsection channels of the coupling data unit generate attitude error signals, which are sent to the attitude indicators for display. These error signals are used by the digital autopilot program in the primary guidance computer to activate RCS thrusters for LM attitude correction. LM acceleration due to thrusting is sensed by three accelerometers, which are mounted on the stable member with their input axes orthogonal. The resultant signals (velocity changes) from the accelerometer loops are supplied to the computer, which calculates the total LM velocity.

Two normal modes of operation achieve attitude control: automatic and attitude hold. In addition to these two modes, there is a minimum impulse mode and a four-jet manual override mode. Either of the two normal modes may be selected on the primary guidance mode control switch.

In automatic mode, all navigation, guidance, and flight control is handled by the primary guidance computer. The computer calculates the desired or preferred attitude, generates the required thruster commands and routes them to the attitude and translation control assembly which fires the selected thruster.

Attitude hold mode is a semiautomatic mode in which either astronaut can command attitude change at an angular rate proportional to the displacement of his attitude controller. The LM holds the new attitude when the controller is brought back to its neutral (detent) position. During primary guidance control, rate commands proportional to controller displacement are sent to the computer. The computer processes these commands and generates thruster commands for the attitude and translation control assembly.

Minimum impulse mode enables the astronaut to control the LM with a minimum of fuel consumption. Each movement of the attitude controller out of its detent position causes the primary guidance computer to issue commands to the appropriate thrusters. The controller must be returned to the neutral position between each impulse command. This mode is selected by DSKY entry only while the control electronics section is in attitude hold. In this mode, the astronaut must perform his own rate damping and attitude steering.

Manual override also is known as the hardover mode. In certain contingencies that may require an abrupt attitude maneuver, the attitude controller can be displaced to the maximum limit (hardover position) to command an immediate attitude change about any axis. This displacement applies signals directly to the RCS solenoids to fire four thrusters that provide the desired maneuver. This maneuver can override any other attitude control mode.

There's from this link: http://www.apollosaturn.com/Lmnr/gn.htm

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dseagrav
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« Reply #9 on: July 24, 2007, 04:14:47 PM »

Actually, the LM and CM control systems are entirely different. The LM is much more dependent on computers.
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Coussini
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« Reply #10 on: July 24, 2007, 04:53:13 PM »

Actually, the LM and CM control systems are entirely different. The LM is much more dependent on computers.


OK... but do you have any document according to your answer. It probably very important to have all document if we want to have a good simulation of Apollo. If you see the white image (just before this post) about the ATTITUDE CONTROL SUBSYSTEM (ACS), you can see that it able to perform an automatic controling of attitude. Wink
« Last Edit: July 24, 2007, 04:59:14 PM by Coussini » Logged

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Swatch
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jasonims
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« Reply #11 on: July 24, 2007, 05:02:08 PM »

ok, now do we know that's how the ORDEAL did it?
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My Project Apollo Work:
CM Visual
 -VC (~75% complete: texture work beginning again; mesh-78%; texture-70%)
Propulsion Particle Improvements (Focused on S1B right now, BETA 1.0 has been commited)
New Docking Method (~50% complete: research complete; coding partially completed, testing not underway)

Future Work:  (if it's here, it's deemed unnecessary to upcoming release)

Older Work:  (if it's here, it's fair game to whoever wants to improve)
EMS Implementation (committed: minor flaws, but groundwork is there, needs extensive testing)
EMS scrolls (committed: not refined, but usable)
SM Visual (committed: mesh-finished, texture-60%; possibly revisited in future)
J2 Texture (commited: room for improvement)
LRV (committed: mesh-finished, texture-90%; in future a ground up rebuild may be in order, but not on my plans)
Coussini
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« Reply #12 on: July 24, 2007, 05:10:20 PM »

ok, now do we know that's how the ORDEAL did it?

I suppose that the ORDEAL work like we said. The real way to confirm this theory, is to find an official  document on this.

Now do we know that's how the Automatic Attitude control the RCS ?  Rolling Eyes
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Tschachim
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« Reply #13 on: July 25, 2007, 10:03:55 AM »

I suppose that the ORDEAL work like we said. The real way to confirm this theory, is to find an official  document on this.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19740026211_1974026211.pdf

Now do we know that's how the Automatic Attitude control the RCS ?  Rolling Eyes

Coussini, I'm not sure if you understood dseagrav correctly, but please be aware of that the LM RCS stuff you posted has nothing to do neither with the CSM nor with the ORDEAL (also not with the LM ORDEAL).

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Tschachim
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Tschachim
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« Reply #14 on: July 25, 2007, 10:08:30 AM »

You may have to just wait but I'll see if I can come up with some psuedo-code to imitate what it is doing.

I just would like to ask if you're going to work on the ORDEAL. If not (or if you still planning to do any pseudo stuff) I'd take a look at that.

Cheers
Tschachim

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