Now that the IK engine is working like I want. I can add more functionality to it.

I first start with a self-balancing positionning. So every time the vinMoov is ask to move a body part, the ik engine will adjust the rest of his body so the vinMoov can keep is balance (in theory, that will remain to see if it could work with a real inMoov) 

At the start of the video, the vinMoov is standing on his left feet. Notice that the vinMoov is slighty tilting to his left with the right leg doing a counterweight to his upper body. That position is taken by the ik engine without any input other than setting the left leg as staying to the ground.

In the rest of the video, i'm playing with the ankle, knee and hip servo slider. The vinMoov execute and keep a much more decent overall position. Without the self-balancing positionning, the vinMoov will have just shift his upper body toward the back to the front.

It's kinda amazing how 20 lines of code can do