Evaluation of Methods for 3D Environment Reconstruction with Respect to Navigation and Manipulation Tasks for Mobile Robots

Abstract: The field of 3-D-environment reconstruction has been subject to various research activities in recent years. The applications for mobile robots are manifold. First, for navigation tasks (especially SLAM), the perception of 3-D-obstacles has many advantages over navigation in 2-D-maps, as it is commonly done. Objects that are located hanging above the ground can be recognized and furthermore, the robots gain a lot more information about its operation area what makes localization easier. Second, in the field of tele-operation of robots, a visualization of the environment in three dimensions helps the tele-operator performing tasks. Therefore, a consistent, dynamically updated environment model is crucial. Third, for mobile manipulation in a dynamic environment, an on-line obstacle detection and collision avoidance can be realized, if the environment is known. In recent research activities, various approaches to 3-D-environment reconstruction have evolved. Two of the most promising methods are FastSLAM and 6-D-SLAM. Both are capable of building dense 3D environment maps on-line. The first one uses a Particle Filter applied on extracted features in combination with a robot system model and a measurement model to reconstruct a map. The second one works on 3-D point cloud data and reconstructs an environment using the ICP algorithm. Both of these methods are implemented in GNU C++. Firstly, FastSLAM is implemented. The object-oriented programming technique is used to build up the Particle and Extended Kalman Filters. Secondly, 6-D SLAM is implemented. The concept of inheritance in C++ is used to make the implementation of ICP algorithm as much generic as possible. To test our implementation a mobile robot called Care-O-bot 3 is used. The mobile robot is equipped with a color and a time-of-fight camera. Data sets are taken as the robot moves in different environments and our implementation of FastSLAM and 6-D SLAM is used to reconstruct the maps.