Meeting Sept 10: Dana's dream

[shae-wat]

Today Dana requested refactoring such that springs can be put around all joints. He recommended starting with a single joint. This will handle "stiffness" issues in the current model

[josephcooper]

All the joints already have springs around them. That's what makes the
inverse dynamics possible. The spring pulls the joint into place and we
read off how much force the spring used. If you play with the Joints tab
of the GUI and control a specific joint, (e.g., R.Elbow X) you'll see that
as you move the slider back and forth, the joint does the appropriate
thing. However, if you move the slider really quickly, the joint will
oscillate a little bit because of the springiness of the controller. What
is lacking is a way to directly control the spring parameters/gains. The
text box next to each joint slider is a threshold on the amount of force
the spring can exert. But it wouldn't be too hard to make it so that you
can control the gains as well. Right now they're all really really stiff.