TABLE OF CONTENTS Edward R. Scheinerman, Johns Hopkins University, Baltimore, MD
Gregory S. Chirikjian, Johns Hopkins University, Baltimore, MD
David Stein, Johns Hopkins University, Baltimore, MD
We develop a methodology for absolute encoding of spherical motion. This is accomplished by painting the surface of a moving ball in two colors and sensing the color at a finite set of points. We show how the painting of a ball in two colors should be performed, and how the point measurements can resolve an arbitrary rotation to within a range depending on the number of sensors and the painting of the ball.
We consider the following problem: A ball is held in a housing, but is free to rotate arbitrarily. How can we determine the orientation of the ball?
We solve this problem by painting the surface of the ball with two colors (black and white). Fixed point sensors are located in the housing and we determine the orientation based on the feedback from these sensors. In this paper we present a technique for painting the surface of the ball, and how to decode the orientation of the ball based on the sensor readings.
The need to determine the orientation of a ball undergoing spherical motion arises in several scenarios. One application area is the feedback control of camera pointing devices used in robot vision [2]. Another application area is in the design of an optical mouse/trackball (see [1, 18] and references therein). Figure 1 illustrates another application in which an array of...
