Centroidal Momentum Matrix of a humanoid robot: Structure and properties

The centroidal momentum of a humanoid robot is the sum of the individual link momenta, after projecting each to the robotpsilas Center of Mass (CoM). Centroidal momentum is a linear function of the robotpsilas generalized velocities and the centroidal momentum matrix is the matrix form of this function. This matrix has been called both a Jacobian matrix and an inertia matrix by others. We show that it is actually a product of a Jacobian and an inertia matrix.