Laser tagging: An approach for rapid robot trajectory definition

Abstract

This paper describes directed laser tagging as an approach to define robot trajectories for low volume applications. The method employs a free-standing laser that is used to define a goal point, a 3D point on an object of interest. Biclops, a directed stereo vision system, uses triangulation to compute the coordinates of the 3D point. A trajectory is defined by collecting a sequence of quasi-static points designated by the free-standing laser. This trajectory can be executed by the robot in 3D space either on the fly or stored for subsequent execution. While a single robot is needed to capture the laser-tagged points, we use a second robot to verify that the 3D point was computed correctly. The first robot carries Biclops and computes the coordinates of the points designated by the free-standing laser. The second robot, which carries a laser, receives the 3D point information from the first robot. Then, the second robot aims at the free-standing laser point. Ideally, the two laser points will overlap. Directed laser-tagging is a rapid way to obtain 3D points compared to other traditional methods including teach-pendants and off-line programming. Experiments show that the error between the laser designated points and the vision acquired points is typically less than 3 mm.