The basic Equation 7 for an Multibody system is based on the Jacobian matrices for translational and rotational motion (JTi and JRi),and the principles of linear(˙pi−fe
i = 0) andangular (˙li − mei= 0) momentum (with linear and angular momentum pi and li, applied forces and moments fei and mei=0) of all n bodies. Noting the translational parts in frame I and the rotational ones in the corresponding body reference frame Ki (with KiI(Si)i noted in the corresponding reference frame Ki) and choosing the centers of gravity Si as reference points,Equation 7 may be rewritten to Equation 9 with the relations corresponding to Equation 8 (the cross product is replaced by a matrix operation: ω × r = ˜ ωr)