Skeleton Robot

I'm not sure we would want a robot who was a lot like a person. Maybe we would prefer to have our robots be more like machines. In any case, I've been wondering if it might be possible to build a robot using a human being as a model. Not just the overall shape, but model it on the human skeleton. We would use reinforced plastic for the bones, some other sort of plastic for cartilage, and nylon or fiberglass for tendons. Muscles would be a bit of a trick, but we might be able to use balloons. A deflated sphere can be extended (without stretching) to one and half times it's diameter. Attach "tendons" to opposite ends of the sphere, and inflate it with fluid and it will draw the two ends closer together. You wouldn't get much contraction with just one ball, but several in a row and you could get some actual movement. Cover the whole thing with a plastic skin and you could have a reasonable mechanical facsimile of a person. I suspect the problem would be the vast number of muscles that would need to be controlled, and if we were doing this all hydraulically, that would mean vast numbers of tubes. Of course, we could use electrical valves on the balloon "muscles" and just use one major pressure line to serve all of them. Wires take less space than tubes. Even if it didn't work for building robots, I wonder if it might work for building prosthetics?