Given some 3 x 3 rotation matrix with some constant acceleration A, I would like to find the component acceleration the three directions, ie, Ax,Ay,Az.
Though it's not difficult to just "reinvent the wheel", I am wondering if there's a Matlab function that does this already, particular in the Aerospace toolbox?
An NxN rotation matrix has N (N-1) / 2 embedded angles. The rotation of a unit right-hand-rule coordinate system into the orientation of R requires these many rotations. In your case there are three angles.
No, Matlab does not have such a built in function. I, too, rolled my own. Take care with the arc-tan's you'll need, certainly use the atan(y, x) form so that you don't lose a 180 deg rotation.