I have made great progress this last week: added body joints (2 DoF) and articulated ears (2 DoF each) to display emotion and make it more expressive.

In total, robot now has 17 DoF: body 2, neck 3, ears 2 × 2, arms 5 × 2. I had to upgrade the power supply to manage that.

On the software side, the arm IK is starting to give promising results (it can move the arm just by using x, y, z coordinates).