[choreonoid-users 00027] Doubt about ZMP calculation

[Luis Filipe Rossi]

Hello,

I was trying to understand how the whole-body ZMP is calculated at
choreonoid so i started to read the source files.

At the *void BodyLoaderImpl::setSegmentProperties *the Moment of Inertina
matrix is calculated according to the folloing formulas

    //  Mass = Sigma mass                 //
    //  C = (Sigma mass * T * c) / Mass   //
    //  I = Sigma(R * I * Rt + G)       //
    //  R = Rotation matrix part of T     //
    //  G = y*y+z*z, -x*y, -x*z, -y*x, z*z+x*x, -y*z, -z*x, -z*y, x*x+y*y
 //
    //  (x, y, z ) = T * c - C        //

Just to confirm if i understood correctly . The Moment od Inertia is
calculated referenced to the to Base link and not to the Joint rotation
axis nor to the link center of mass, correct?

Regards,

-- 
Luís Filipe Rossi
Electrical Engineer
Biomechatronics Lab. / Grupo de Sensores Integráveis e Sistemas
Escola Politécnica
Universidade de São Paulo
Cel. +55 (11) 97662-9234
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