One aspect is a robot system comprising a flexible artificial skin operable to be mechanically flexed under the control of a computational system. A movable lead screw is coupled to the displacement selection controller so as to be capable of altering the position thereof, and a lead screw positioner is provided for selectively moving, or preventing the moving of, the movable lead screw by extending and retracting the lead screw through a threaded opening. The fiber optic line preferably extends through a pilot gas line, a flame front generator line, or other protective conduit so that the fiber optic line can be cooled and purged by pilot gas, instrument air, or other cooling gas media which is continuously delivered through the conduit. A typical composition comprises 0. The arm can couple to the gear housing in a first configuration to provide torque to rotate the housing about the shaft axis in the first direction when the arm is pressed downward.