about the ground force collected

[Hang Xu]

Hi, I am Hang
I feel confused when I try to use the ground force file to calculate the force in each joint by taking the inverse dynamics step. In the ground force file, I noticed the coordinate and force of X,Y,Z are collected, another titled Mz, what does it mean? does it mean the moment component in the force transducer coordinate system as the instruction book of Bertec plate. if it is so, I can calculate the torque in Z, but I also need the data of My and Mx to calculate the torque_x and torque_y.
I do not know whether my understanding is right or not, waiting for your reply.

[B.J. Fregly]

Hi Hang,

The ground reactions are reported as three force components, a center of pressure location (two components in the plane of the floor), and a moment component (superior-inferior direction) calculated about the center of pressure. I don't recall the precise order of these quantities in the data files. The center of pressure is, by definition, the point in the plane of the floor about which the other two components of moment go to zero. So there are six ground reaction quantities in all for each foot.

I hope that information clarifies the ground reaction data contained in the data files.

B.J. Fregly