Two Methods of Determining the Ellipses and Ellipsoids of Positioning Accuracy ofRobot Manipulators

摘要

When analyzing the problem of the positioning accuracy of robot manipulators itis important to know how large may random deviations of the hand be from the desired position if the joint positioning errors possess a normal distribution. Two methods of determining the ellipses and ellipsoids of probability concentration are compared. The first is based on the standard procedure of the probability calculus. The second approximate method consists in finding at first the polygon or polyhedron of the positioning accuracy, and then in finding the ellipse or ellipsoid of the principal axes and second order moments coinciding with those of the polygon or polyhedron respectively. Examples of application demonstrate that these two methods give very close results.