Before revision: In robotics the common normal of two non-intersecting joint axes is a line perpendicular to both axes.Introduction to Robotics by Saeed Niku ISBN 0470604468 page 75 The common normal can be used to characterize robot arm links, by using the "common normal distance" and the angle between the link axes in a plane perpendicular to the common normal.Robot manipulators: mathematics, programming, and control by Richard P. Paul 1981 ISBN 026216082X page 51
After revision: The common normal is widely used in the representation of the frames of reference for robot joints and links, and the selection of minimal representations with the Denavit-Hartenberg parameters.In robotics the common normal of two non-intersecting joint axes is a line perpendicular to both axes.Introduction to Robotics by Saeed Niku ISBN 0470604468 page 75 The common normal can be used to characterize robot arm links, by using the "common normal distance" and the angle between the link axes in a plane perpendicular to the common normal.Robot manipulators: mathematics, programming, and control by Richard P. Paul 1981 ISBN 026216082X page 51