Quoting Doug Ausmus <daus...@gmail.com>:

Have you calculated the sampling/control intervals yet? If so, what are the
fastest ones or most critical ones that must absolutely be deterministic?


No, but we have them bounded. There is no need to run the control loop faster than 1000Hz (which is a 25-50Hz *control* bandwidth) as we proved when considering actuator force would destroy the fins, yet I think I can easily make the case that it must be faster than 10Hz (which is a 0.25-0.50Hz *control* bandwidth) due to the fast roll axis dynamics.

So, between 10 and 1000 loops per second. If I had to pick today, I'd say 400Hz.

In that time, we need to be able to perform several 12x12 matrix multiplies, a few martix-vector multiplies, matrix add and subtract operations, and one or two 12x12 inversions (this is pretty typical of an optimal control scheme).

btw, '25Hz *control* bandwidth' means the rocket will follow a 25Hz sine wave 'point in this direction' command of +- 10 degree amplitude with at least +- 7 degree response and less than 90 degrees of phase lag.







_______________________________________________
psas-avionics mailing list
psas-avionics@lists.psas.pdx.edu
http://lists.psas.pdx.edu/mailman/listinfo/psas-avionics

Reply via email to