Abstract

The present invention provides for precision micropositioning of a robotic structure. The micropositioning system includes a number of angular encoders indicating the angular orientations of various robotic elements with respect to one another and optical devices measuring the actual deflection of load bearing arm portions of the robotic structure. A separate optical device may be attached to each load bearing arm of the robotic structure. The optical device includes a target to be disposed at one end of the load bearing arms and an optical detecting system to be disposed at opposing ends of the load bearing arms. The target includes a plurality of light sources generally disposed in a plane and at least one light source disposed outside the plane. The optical detecting system includes first and second linear detector arrays adjacently disposed with longitudinal axes perpendicularly oriented. Each array senses target motion along a single line parallel to its longitudinal axis. An imaging lens and a cylindrical lens are provided for each array to focus images from the target light sources into lines oriented perpendicular to the longitudinal axes of the respective arrays. A portion of these images will remain focused on the detector arrays despite relative motion of the target perpendicular to the respective axes of the arrays. The optical detecting system resolves translational displacement of a target and associated robotic arm end along with pivotal changes in the orientations of the target and robotic arm end.

Other References

• IBM Technical Disclosure Bulletin, vol. 23, No. 4, 9-1980, "Dual-Range Optical Position Transducer," Estes