I need to model the planetary gear-train with transformation matrices of 1 sun and 2 planets system, with no ring and an "arm" or carrier holding the gears ,like in the second picture. I already have a dynamical model of the simple system derived analytically, but I need to model it dimensionally to be able to specify the spatial relationships—the relative positions and orientations of the epicyclic geartrain to simulate it.
I only have experience deriving homogeneous transformation matrices of robot joints but I don't know where to star for a gear train system or what method to use.
I'm not sure about which frames of reference to use and how to set up the coordinate system between the gears correctly, for example; what would be the difference between considering a fixed frame of reference for the sun vs a rotating frame of reference? Also, I don't know which and how to include variables like mass, stiffness and damping, like shown in the first picture (for example).