Admittance control of the feet
Now that the CoM admittance is basically closed, we should start thinking about the admittance on the feet. Eventually, this will require the full implementation of the force distribution (#63), but I think we can do some tests which only concern the admittance on the feet without the whole controller on.
Caron's paper implements admittance control on the ankles (#22) which only regulates the roll and pitch of the ankles, plus a special foot-force difference control which controls the difference in the forces exerted on the ground along the z-axis.
It was said long ago that it would be nice to directly switch to full-fledged admittance control of the feet, using the results of #32 (closed).
I am currently investigating the application of the end-effector admittance controller to the feet (on a separate branch). They seem to be easily applicable.
I like the idea of directly switching to 6D-admittance, but @tflayols is not convinced. I feel we should discuss it.