I was recently reading that those artificial muscles had the highest power/weight ratio while electric motors only have a ratio of less than 100:1. As electrical engineer I have never worked with pneumatics before and do not have a big idea about air pumps. My question is, how much will this ratio change if we consider an autonomous system. On one side, the McKibben actuators + air pumps and valves + energy source and on the other side, electric motors + energy source. As an example, let suppose that somebody found a way to model and control the artificial muscles as good as the electric motors and make two autonomous walking leg models, which one would have a higher resulting power/weight ratio ?