ABSTRACT

Coordinate frame transformations are fundamental to robotics. Coordinating data from multiple models and sensors is accomplished through coordinate transformations. Fortunately, robot operating system (ROS) provides extensive support for coordinate transformations. Since transforms are ubiquitous in ROS and in robotics in general, it is important to have an understanding of how coordinate transforms are handled in ROS. As long as a complete tree is published connecting frames of interest, the transform listener can be used to transform all sensor data into a common reference frame, thus allowing for display of sensory data from multiple sources in a common view. Since coordinate transforms are so common in robotics, ROS provides a powerful tf package for handling transforms. The example code prints components of this transform, using accessor functions of transform objects. In addition to tf operations, an alternative library known as Eigen can be more convenient for performing linear-algebra operations.