I had this issue with the piDog head shaking badly with each movement. I first attempted to resolve it using the program bit submitted by user DarrenL, however my servo shake was so bad this did not resolve it. The rubber band method does indeed fix the problem, but I wanted something that looked better. I ended up using a pair of tension springs (4.5mm O.D. x 45mm length). This worked amazingly well, with the added bonus that the springs actually look like they are part of the dog. They just blend right in. Hope this helps somebody.
