Controlling a robotic arm, a prosthetic hand or a rehabilitation device is harder than it looks. Picking up an egg, for example, requires just the right amount of force: too little and it falls, too much and it breaks.Controlling a robotic arm, a prosthetic hand or a rehabilitation device is harder than it looks. Picking up an egg, for example, requires just the right amount of force: too little and it falls, too much and it breaks.[#item_full_content]