Have I been here before? Learning to Close the Loop with LiDAR Data in Graph-Based SLAM

This work presents an extension of graph-based SLAM methods to exploit the potential of 3D laser scans for loop detection. Every high-dimensional point cloud is replaced by a compact global descriptor, whereby a trained detector decides whether a loop exists. Searching for loops is performed locally in a variable space to consider the odometry drift. Since closing a wrong loop has fatal consequences, an extensive verification is performed before acceptance. The proposed algorithm is implemented as an extension of the widely used state-of-the-art library RTAB-Map, and several experiments show the improvement: During SLAM with a mobile service robot in changing indoor and outdoor campus environments, our approach improves RTABMap regarding total number of closed loops. Especially in the presence of significant environmental changes, which typically lead to failure, localization becomes possible by our extension. Experiments with a car in traffic (KITTI benchmark) show the general applicability of our approach. These results are comparable to the state-of-the-art LiDAR method LOAM. The developed ROS package is freely available.© 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works

Evaluation of RGB-D SLAM in Large Indoor Environments

Simultaneous localization and mapping (SLAM) is one of the key components of a control system that aims to ensure autonomous navigation of a mobile robot in unknown environments. In a variety of practical cases a robot might need to travel long distances in order to accomplish its mission. This requires long-term work of SLAM methods and building large maps. Consequently the computational burden (including high memory consumption for map storage) becomes a bottleneck. Indeed, state-of-the-art SLAM algorithms include specific techniques and optimizations to tackle this challenge, still their performance in long-term scenarios needs proper assessment. To this end, we perform an empirical evaluation of two widespread state-of-the-art RGB-D SLAM methods, suitable for long-term navigation, i.e. RTAB-Map and Voxgraph. We evaluate them in a large simulated indoor environment, consisting of corridors and halls, while varying the odometer noise for a more realistic setup. We provide both qualitative and quantitative analysis of both methods uncovering their strengths and weaknesses. We find that both methods build a high-quality map with low odometry noise but tend to fail with high odometry noise. Voxgraph has lower relative trajectory estimation error and memory consumption than RTAB-Map, while its absolute error is higher.Comment: This is a pre-print of the paper accepted to ICR 2022 conferenc

Architecture de contrôle d'un robot de téléprésence et d'assistance aux soins à domicile

La population vieillissante provoque une croissance des coûts pour les soins hospitaliers. Pour éviter que ces coûts deviennent trop importants, des robots de téléprésence et d’assistance aux soins et aux activités quotidiennes sont envisageables afin de maintenir l’autonomie des personnes âgées à leur domicile. Cependant, les robots actuels possèdent individuellement des fonctionnalités intéressantes, mais il serait bénéfique de pouvoir réunir leurs capacités. Une telle intégration est possible par l’utilisation d’une architecture décisionnelle permettant de jumeler des capacités de navigation, de suivi de la voix et d’acquisition d’informations afin d’assister l’opérateur à distance, voir même s’y substituer. Pour ce projet, l’architecture de contrôle HBBA (Hybrid Behavior-Based Architecture) sert de pilier pour unifier les bibliothèques requises, RTAB-Map (Real-Time Appearance-Based Mapping) et ODAS (Open embeddeD Audition System), pour réaliser cette intégration. RTAB-Map est une bibliothèque permettant la localisation et la cartographie simultanée selon différentes configurations de capteurs tout en respectant les contraintes de traitement en ligne. ODAS est une bibliothèque permettant la localisation, le suivi et la séparation de sources sonores en milieux réels. Les objectifs sont d’évaluer ces capacités en environnement réel en déployant la plateforme robotique dans différents domiciles, et d’évaluer le potentiel d’une telle intégration en réalisant un scénario autonome d’assistance à la prise de mesure de signes vitaux. La plateforme robotique Beam+ est utilisée pour réaliser cette intégration. La plateforme est bonifiée par l’ajout d’une caméra RBG-D, d’une matrice de huit microphones, d’un ordinateur et de batteries supplémentaires. L’implémentation résultante, nommée SAM, a été évaluée dans 10 domiciles pour caractériser la navigation et le suivi de conversation. Les résultats de la navigation suggèrent que les capacités de navigation fonctionnent selon certaines contraintes propres au positionement des capteurs et des conditions environnementales, impliquant la nécessité d’intervention de l’opérateur pour compenser. La modalité de suivi de la voix fonctionne bien dans des environnements calmes, mais des améliorations sont requises en milieu bruyant. Incidemment, la réalisation d’un scénario d’assistance complètement autonome est fonction des performances de la combinaison de ces fonctionnalités, ce qui rend difficile d’envisager le retrait complet d’un opérateur dans la boucle de décision. L’intégration des modalités avec HBBA s’avère possible et concluante, et ouvre la porte à la réutilisabilité de l’implémentation sur d’autres plateformes robotiques qui pourraient venir compenser face aux lacunes observées sur la mise en œuvre avec la plateforme Beam+

The Complete Reference (Volume 4)

This is the fourth volume of the successful series Robot Operating Systems: The Complete Reference, providing a comprehensive overview of robot operating systems (ROS), which is currently the main development framework for robotics applications, as well as the latest trends and contributed systems. The book is divided into four parts: Part 1 features two papers on navigation, discussing SLAM and path planning. Part 2 focuses on the integration of ROS into quadcopters and their control. Part 3 then discusses two emerging applications for robotics: cloud robotics, and video stabilization. Part 4 presents tools developed for ROS; the first is a practical alternative to the roslaunch system, and the second is related to penetration testing. This book is a valuable resource for ROS users and wanting to learn more about ROS capabilities and features.info:eu-repo/semantics/publishedVersio

From Perception to Navigation in Environments with Persons: An Indoor Evaluation of the State of the Art

Research in the field of social robotics is allowing service robots to operate in environments with people. In the aim of realizing the vision of humans and robots coexisting in the same environment, several solutions have been proposed to (1) perceive persons and objects in the immediate environment; (2) predict the movements of humans; as well as (3) plan the navigation in agreement with socially accepted rules. In this work, we discuss the different aspects related to social navigation in the context of our experience in an indoor environment. We describe state-of-the-art approaches and experiment with existing methods to analyze their performance in practice. From this study, we gather first-hand insights into the limitations of current solutions and identify possible research directions to address the open challenges. In particular, this paper focuses on topics related to perception at the hardware and application levels, including 2D and 3D sensors, geometric and mainly semantic mapping, the prediction of people trajectories (physics-, pattern- and planning-based), and social navigation (reactive and predictive) in indoor environments

Robotic Maintenance and ROS - Appearance Based SLAM and Navigation With a Mobile Robot Prototype

Robotic maintenance has been a topic in several master's theses and specialization projects at the Department of Engineering Cybernetics (ITK) at NTNU over many years. This thesis continues on the same topic, with special focus on camera-based mapping and navigation in conjunction with automated maintenance, and automated maintenance in general. The objective of this thesis is to implement one or more functionalities based on camera-based sensors in a mobile autonomous robot. This is accomplished by acquiring knowledge of existing solutions and future requirements within automated maintenance. A mobile robot prototype has been configured to run ROS (Robot Operating System), a middleware framework that is suited to the development of robotic systems. The system uses RTAB-Map (Real-Time Appearance Based Mapping) to survey the surroundings and a built navigation stack in ROS to navigate autonomously against easy targets in the map. The method uses a Kinect for Xbox 360 as the main sensor and a 2D laser scanner to the surveying and odometry. It is also developed functional concepts for two support functions, an Android application for remote control over Bluetooth and a remote central (OCS) developed in Qt. Remote Central is a skeletal implementation that is able to remotely control the robot via WiFi, as well as to display video from the robot's camera. Test results, obtained from both live and simulated trials, indicate that the robot is able to form 3D and 2D map of the surroundings. The method has weaknesses that are related to the ability to find visual features. Laser Based odometry can be tricked when the environment is changing, and when there are few unique features. Further testing has demonstrated that the robot can navigate autonomously, but there is still room for improvement. Better results can be achieved with a new movable platform and further tuning of the system. In conclusion, ROS works well as a development tools for robots, and the current system is suitable for further development. RTAB-Maps suitability for use on an industrial installation is still uncertain and requires further testing