AngularMomentum[A,b]

A: name of defined observer

b: name of defined triad

The function AngularMomentum returns the angular momentum of a rigid body with reference triad b relative to the observer A.

The angular momentum is expressed using the symbols Inertia11, Inertia12, and so on, to represent the components of the moment of inertia matrix.

Remember to invoke DeclareStates prior to using AngularMomentum.

Restart;
DeclareObservers[A];
DeclarePoints[A];
DeclareTriads[a,b];
DefineObservers[{A,A,a}];
DefineTriads[a,b,{q1,1},{q2,3},{q3,1}];
DeclareStates[q1,q2,q3]; 
AngularMomentum[A,b]

$\left\{''Type''\to ''Vector'',''Size''\to 1,1\to \left\{''Coordinates''\to \left\{\mathrm{Inertia13}\left(\mathrm{Sin}\left[\mathrm{q2}\right]\mathrm{Sin}\left[\mathrm{q3}\right]{\mathrm{q1}}^{\prime }+\mathrm{Cos}\left[\mathrm{q3}\right]{\mathrm{q2}}^{\prime }\right)+\mathrm{Inertia12}\left(-\mathrm{Cos}\left[\mathrm{q3}\right]\mathrm{Sin}\left[\mathrm{q2}\right]{\mathrm{q1}}^{\prime }+\mathrm{Sin}\left[\mathrm{q3}\right]{\mathrm{q2}}^{\prime }\right)+\mathrm{Inertia11}\left(\mathrm{Cos}\left[\mathrm{q2}\right]{\mathrm{q1}}^{\prime }+{\mathrm{q3}}^{\prime }\right),\mathrm{Inertia23}\left(\mathrm{Sin}\left[\mathrm{q2}\right]\mathrm{Sin}\left[\mathrm{q3}\right]{\mathrm{q1}}^{\prime }+\mathrm{Cos}\left[\mathrm{q3}\right]{\mathrm{q2}}^{\prime }\right)+\mathrm{Inertia22}\left(-\mathrm{Cos}\left[\mathrm{q3}\right]\mathrm{Sin}\left[\mathrm{q2}\right]{\mathrm{q1}}^{\prime }+\mathrm{Sin}\left[\mathrm{q3}\right]{\mathrm{q2}}^{\prime }\right)+\mathrm{Inertia21}\left(\mathrm{Cos}\left[\mathrm{q2}\right]{\mathrm{q1}}^{\prime }+{\mathrm{q3}}^{\prime }\right),\mathrm{Inertia33}\left(\mathrm{Sin}\left[\mathrm{q2}\right]\mathrm{Sin}\left[\mathrm{q3}\right]{\mathrm{q1}}^{\prime }+\mathrm{Cos}\left[\mathrm{q3}\right]{\mathrm{q2}}^{\prime }\right)+\mathrm{Inertia32}\left(-\mathrm{Cos}\left[\mathrm{q3}\right]\mathrm{Sin}\left[\mathrm{q2}\right]{\mathrm{q1}}^{\prime }+\mathrm{Sin}\left[\mathrm{q3}\right]{\mathrm{q2}}^{\prime }\right)+\mathrm{Inertia31}\left(\mathrm{Cos}\left[\mathrm{q2}\right]{\mathrm{q1}}^{\prime }+{\mathrm{q3}}^{\prime }\right)\right\},''Triad''\to b\right\}\right\}$

DeclareStates, LinearVelocity, AngularVelocity, LinearMomentum