Meadville Space Center

Project Apollo - NASSP => Programming => Topic started by: dseagrav on March 22, 2006, 12:31:13 AM



Title: The ECA is almost done, but I have a question...
Post by: dseagrav on March 22, 2006, 12:31:13 AM
My question involves the use of auto-rate attitude hold. As I understand it, it checks the current attitude vs. the GDC+ASCP error data from the GDC. If the error between the GDC attitude and the ASCP-set attitude is outside of the limits of the current deadband, it fires jets to reduce the error to inside the deadband. This works. The issue is, what do I do when I get to within the limits of the deadband? The manual isn't clear. Does it simply wait until the ship hits the other side of the deadband (at which point it reverses and "bounces" around inside the deadband unless the crew manually kills rotation) or does it try reducing the remaining rate to zero?

Once I solve that, and get proportional-rate and pseudo-rate feedback working, it's commitable.


Title: The ECA is almost done, but I have a question...
Post by: dseagrav on March 22, 2006, 12:43:14 PM
This is grand. I just found an account of the crew of Apollo 17 complaining about the very same SCS behavior I am seeing and suggesting the use of two quads for roll and not all four. Amazing. I have to turn the commanded rate down a little, I guess. Good thing to know that I'm not the only person who thought this was a bit strange!


Title: The ECA is almost done, but I have a question...
Post by: Christophe on March 23, 2006, 05:12:44 PM
Hi dseagrav. I'm not sure understanding you very well. I believe the issue you're talking about has something to do with the limit cycle switch.
May be you can read about this feature on the AOH?