# FDK algorithm

Hello !
I’m writting a paper including a description of the model I developed. In this model I used the FDK algorithm.

I would have been interested in explaining FDK in detail. My idea was to create a process scheme as the one attached.

Here is a short explanation (based on my understand )
As an inverse dynamic problem, positions of the segments are the input variables (q). They are derived twice (velocity \dot{q} and acceleration \ddot{q}) and used to solve the motion equation.
From motion equation, muscular (F^(MT)) and reaction forces (E) are calculated.

Two cases :

• If there is NOT a quasi-static equilibrium between forces and position of segments refered in the FDK, then q_{FDK} is updated and a new iteration of the same process begins.
• If there is a quasi-static equilibrium between forces and position of segments refered in the FDK, then go to the next step.

1/ if the scheme/explanation are right !
2/ if the scheme/explanation are clear enough

Thanks a lot for your support !
Lauranne

Hello,
I was working on it and have some updates ; could you give me your opinion ?
1/ see attached figrue
2/ E corresponds to the external forces applied to the body by the environment. Then it’s not calculated from the equation motion but, rather, is an input.