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tures.Kinesthetic sensing is a necessity for the walking robots in Chap- ter 6, and units with hands need broader abilities.Two examples with cyborglike elements have been developed for use in space: NASAs Robonaut, and the four-fingered DLR Hand II, developed at the Deutschen Zentrum für Luft- und Raumfahrt (DLR), the German Aerospace Center. In both Robonaut and the DLR Hand II, human operators remotely perform manual tasks using video feeds that dis- play what the robotic hand is doing. But the humans do better when the forces and textures felt by the robotic hand are fed back to their hands, via data gloves.

The transmission of sensory data from a robotic hand to a real one requires ingenious and extensive hardware.The force sensors de- veloped for the DLR Hand II are tiny enough to fit into its fingertips, and according to Robert Ambrose, who heads the Robonaut group, the unit has more than 150 sensors in its arm and hand, although not all are involved in providing feedback. But even this many sensors is not enough to match the full power of human tactility. Our fingertips and tongue-tip are highly sensitive because touch sensors are densely concentrated there. We do not fully understand this network, and some researchers think its complexity rivals that of the visual system. In any case, it takes clever engineering to make sensors small and numerous enough to be installed at similar high densities.

The engineering challenge is being addressed, however, because of the role artificial touch can play in robotic surgery, a technique that is now commercially available, for instance, in Intuitive Surgicals da Vinci system. Like the NASA and DLR robots, surgical robots are cyborglike rather than autonomous; that is, a trained human surgeon manipulates controls to operate a remote set of surgical instruments. One day, surgeons might be able to operate remotely at accident or battlefield sites anywhere in the world.Another application is already realizedminimally invasive surgery, performed through small bodily incisions typically a centimeter in size.The surgeon sees by way of a tiny video camera called an endoscope, and wields miniature tools, all inserted through the incisions.With the intervention of suitable hard- ware and a computer, the surgeons hand movements are appropri- ately scaled down, and any hand tremors are removed.

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