There are two generalized schools of thought when it comes to robot hand design. You have robot hands that are simple and straightforward and get the job done, like two- or three-finger grippers that can reliably do many (if not most) things well without any fuss. And then you have very complex hands with four fingers and a thumb that are designed to closely mimic human hands, on the theory that human hands were intelligently designed by millions of years of evolution, and we’ve designed all of our stuff around them anyway, so if you want your robot to be able to do as many things as possible as well as possible you want a hand that’s as humanlike as possible.
Because of the inherent complexity of a real human hand, biomimetic anthropomorphic hands inevitably involve lots of compromises to get them to work properly while maintaining a human-ish form factor. Zhe Xu and Emanuel Todorov from the University of Washington, in Seattle, have gone crazy and built the most detailed and kinematically accurate biomimetic anthropomorphic robotic hand that we’ve ever seen, with the ultimate goal of replacing human hands completely.