[ODE] Linear Torque Decoupling

[Kenny Erleben]

Hi All,

I have been looking deeply into the source code and I have come across the
linear torque decoupling step in the joint limit motor and I do not really
understand it, could somebody please clarify what the problem is and why
the torque decoupling works?

I tried to work out a few examples by hand to get a better understanding,
I came up with this example of two rectangular bodies, lying orthogonal to
each other, as shown below in the ascii drawing


                     body 1
                     +---+
                     |   |
                     |   |
                     |   |
                     | X |
                     |   |
+-------------------------+
|                         |
|             X  ------o- |   --> joint axe
|                         |
+-------------------------+
      body 0

Now if I understand correctly any limit or motor force will be horizozntal
(and in real life applied at the spot marked by 'o'), applying the force
halfway beteen the body centers (marked by X's) will as far as I can tell
introduce and unwanted/unexpected torque.

>From what I understand only body 1 will feel a torque from the limit/motor
force, this torque will try to move body 1 against the joint bearings, and
body 0, will feel the effect of all this as a reaction force from its
joint bearings...

Regards

Kenny