If you want to make your next robot be able to use hands like a human the Open Hand project would give you a head start in this direction. Building a cheap model of the complex human hand is no small task but if this campaign is successful I think we will be heading in the right direction.
Via: Make
“The Dextrus hand works much like a human hand. It uses electric motors instead of muscles and steel cables instead of tendons. 3D printed plastic parts work like bones and a rubber coating acts as the skin. All of these parts are controlled by electronics to give it a natural movement that can handle all sorts of different objects.
The hand can be connected to an existing prosthesis using a standard connector to give an amputee another option. It uses stick-on electrodes to read signals from their remaining muscles, which can control the hand, telling it to open or close.
The fingers are individually powered and each one can sense when an object is impeding its movement. This gives it the ability to grasp objects gently and means the fingers can really wrap around unusual shapes to grip them firmly.”