Hopcroft, John E.Joseph, Deborah A.Whitesides, Sue H.2007-04-232007-04-231982-04http://techreports.library.cornell.edu:8081/Dienst/UI/1.0/Display/cul.cs/TR82-486https://hdl.handle.net/1813/6326The classical mover's problem is the following: can a rigid object in 3-dimensional space be moved from one given position to another while avoiding obstacles? It is known that a more general version of this problem involving objects with movable joints is PSPACE complete, even for a simple tree-like structure moving in a 3-dimensional region. In this paper, we investigate a 2-dimensional mover's problem in which the object is a robot arm with an arbitrary number of joints. In particular, we give a polynomial time algorithm for moving an arm confined within a circle from one given configuration to another. We also give a polynomial time algorithm for moving the arm from its initial position to a position in which the end of the arm reaches a given point within the circle. Keywords: robotics, manipulators, mechanical arms, algorithms, polynomial time.1694714 bytes495683 bytesapplication/pdfapplication/postscripten-UScomputer sciencetechnical reporttechnical report