A COMPUTER VISION SYSTEM FOR EXTRAVEHICULAR ACTIVITY HELPER RETRIEVER

The Extravehicular Activity Helper/Retriever (EVAHR) is a free-flying robot currently being developed by the Automation and Robotics Division at the NASA Johnson Space Center to support activities in the neighborhood of Space Station Freedom or planetary habitat. The EVAHR's primary responsibilities are rescue of crew, and retrieval of critical equipment. It will also perform extravehicular activities in cooperation with crew members. The stated responsibilities could never be fulfilled without a robust and versatile real time computer vision system. This paper presents a preliminary design of the EVAHR's vision system and its initial implementation. The preliminary design consists of a vision system planner, and many sub-modules for performing various vision functions. Top-down and bottom-up approaches have been taken for initial implementation of the preliminary design. While the top-down approach focuses on building a control mechanism and laying down a framework for the vision system planner, the bottom-up approach emphasizes the design and implementation of various computation skills such as search, tracking, and pose estimation. Experimental results of the initial implementation are included in the paper.