POGO is starting to move faster than the project manager can keep up with. The parts for the tank have arrived and Dan is ready to machine the last few bits for it, but I haven't got the detail drawings printed out yet! At the rate POGO is moving, POGO will fly before Gizmocopter. I hope Pierce's simulator works out well. (I should probably mention to him that it would probably be better to just model POGO. But he'd kill me after having gone through hell getting all the gizmo parts weighed and the propellers torques and forces figured out. Oh well, the missing part for getting Gizmo flying is also a necessary part for flying POGO.)
Oh, I would, but for another reason. The 6DOF equations in Simulink are written with the assumption that mass properties are constant. That means I would have to, instead of modeling the torques, model the changing level of propellant... and its sloshing. I might just be able to get away with modeling it as a pendulum, but that will be pushing it.
-p
Warning warning -- you are rapidly drifting into dubious simulation territory. I won't say it is completely without value, but modeling propellant slosh when the engines are only just barely characterized at a couple history-free point samples is just silly.
Your control system won't even care much about the changing mass as propellant is depleted. If it works with a couple different masses, it will work sliding between them.
I do model changing propellant mass in my simulator, but I don't worry about slosh.
John Carmack
_______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
