- #1
jstluise
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I have two rigid bodies floating in space that are kinematically constrained by a joint (think of a 2 dof link mechanism floating in space).
I have a body fixed reference frame on each rigid body plus the global space-fixed reference frame. The first rigid body is in the space-fixed reference frame), so its rotational kinetic energy is trivial. However, the second rigid body referenced via the first rigid body's body fixed reference frame.
I'm unsure how to transform the second rigid body's rotation into the global space-fixed frame, which will allow me to get the rotational kinetic energy of the second body.
So basically I have the first rigid body described by ##\vec{r}_{1,0}## and ##\vec{\theta}_{1,0}## where ##1,0## is the 1st body fixed frame relative the space-fixed frame. And for the second rigid body, ##\vec{r}_{2,1}## and ##\vec{\theta}_{2,1}## where ##2,1## is the 2nd body fixed frame relative 1st body fixed frame.
I want to find ##\vec{\theta}_{2,0}##. I imagine my moment of inertia tensor will change also? Right now all my body fixed frames are lined up with the principle moments (i.e. moment of inertia tensors are diagonal).
I have a body fixed reference frame on each rigid body plus the global space-fixed reference frame. The first rigid body is in the space-fixed reference frame), so its rotational kinetic energy is trivial. However, the second rigid body referenced via the first rigid body's body fixed reference frame.
I'm unsure how to transform the second rigid body's rotation into the global space-fixed frame, which will allow me to get the rotational kinetic energy of the second body.
So basically I have the first rigid body described by ##\vec{r}_{1,0}## and ##\vec{\theta}_{1,0}## where ##1,0## is the 1st body fixed frame relative the space-fixed frame. And for the second rigid body, ##\vec{r}_{2,1}## and ##\vec{\theta}_{2,1}## where ##2,1## is the 2nd body fixed frame relative 1st body fixed frame.
I want to find ##\vec{\theta}_{2,0}##. I imagine my moment of inertia tensor will change also? Right now all my body fixed frames are lined up with the principle moments (i.e. moment of inertia tensors are diagonal).