Abstract: A light affixed to the front of a school bus directs a beam of light across a road to enhance a safe crossing of the road by children boarding the bus. At least two red warning lights are mounted upon a front surface of the bus. A controller is operatively connected to the crossing light and warning lights.

Abstract: Machine operations are performed by a robot at a plurality of locations on a workpiece based on off-line data. The off-line data is corrected based on two levels of workpiece/robot alignment. First the robot determines the orientation of a fixture to which the workpiece is mounted by "touching-off" on known reference points (touchblocks) on the fixture. Coordinate data for the location of local features on the workpiece is corrected based on the first level of alignment and the positions of the local features are then sensed to provide a coordinate transformation for subsequent application to nominal machine operation location coordinates. The local features may be preassembly rivets and provide for individualized robot response on a workpiece-by-workpiece basis.

Abstract: A robot "touches off" on the orthagonal touchblock faces of a workpiece holding fixture and the coordinate of the touches along axes nominally normal to the faces provide significant data from which a coordinate transformation indicative of the orientation and location of the touchblocks in the robot frame of reference can be determined. The coordinate transformation is subsequently applied to workpiece coordinates indicative of the location and orientation of the workpiece and/or points thereon.