Добірка наукової літератури з теми "Navigation Among Movable Obstacles"

In this paper, we address the problem of Navigation Among Movable Obstacles (NAMO): a practical extension to navigation for humanoids and other dexterous mobile robots. The robot is permitted to reconfigure the environment by moving obstacles and clearing free space for a path. This paper presents a resolution complete planner for a subclass of NAMO problems. Our planner takes advantage of the navigational structure through state-space decomposition and heuristic search. The planning complexity is reduced to the difficulty of the specific navigation task, rather than the dimensionality of the multi-object domain. We demonstrate real-time results for spaces that contain large numbers of movable obstacles. We also present a practical framework for single-agent search that can be used in algorithmic reasoning about this domain.

Conventional approaches to robot navigation in unstructured environments rely on information acquired from the LiDAR mounted on the robot base to detect and avoid obstacles. This approach fails to detect obstacles that are too small, or that are invisible because they are outside the LiDAR’s field of view. A possible strategy is to integrate information from other sensors. In this paper, we explore the possibility of using depth information from a movable RGB-D camera mounted on the head of the robot, and investigate, in particular, active control strategies to effectively scan the environment. Existing works combine RGBD-D and 2D LiDAR data passively by fusing the current point-cloud from the RGB-D camera with the occupancy grid computed from the 2D LiDAR data, while the robot follows a given path. In contrast, we propose an optimization strategy that actively changes the position of the robot’s head, where the camera is mounted, at each point of the given navigation path; thus, we can fully exploit the RGB-D camera to detect, and hence avoid, obstacles undetected by the 2D LiDAR, such as overhanging obstacles or obstacles in blind spots. We validate our approach in both simulation environments to gather statistically significant data and real environments to show the applicability of our method to real robots. The platform used is the humanoid robot R1.

In the near future, it’s expected that unmanned aerial vehicles (UAVs) will become ubiquitous surrogates for human-crewed vehicles in the field of border patrol, package delivery, etc. Therefore, many three-dimensional (3D) navigation algorithms based on different techniques, e.g., model predictive control (MPC)-based, navigation potential field-based, sliding mode control-based, and reinforcement learning-based, have been extensively studied in recent years to help achieve collision-free navigation. The vast majority of the 3D navigation algorithms perform well when obstacles are sparsely spaced, but fail when facing crowd-spaced obstacles, which causes a potential threat to UAV operations. In this paper, a 3D vision cone-based reactive navigation algorithm is proposed to enable small quadcopter UAVs to seek a path through crowd-spaced 3D obstacles to the destination without collisions. The proposed algorithm is simulated in MATLAB with different 3D obstacles settings to demonstrate its feasibility and compared with the other two existing 3D navigation algorithms to exhibit its superiority. Furthermore, a modified version of the proposed algorithm is also introduced and compared with the initially proposed algorithm to lay the foundation for future work.

SUMMARYA non-holonomic robot with a bounded control input travels in a dynamic unknown 3D environment with moving obstacles. We propose a 3D navigation strategy to reach a given final destination point while avoiding collisions with obstacles. A formal analysis of the proposed 3D robot navigation algorithm is given. Computer simulation results and experiments with a real flying autonomous vehicle confirm the applicability and performance of the proposed guidance approach.

This paper introduces a practical navigation approach for nonholonomic Unmanned Aerial Vehicles (UAVs) in 3D environment settings with numerous stationary and dynamic obstacles. To achieve the intended outcome, Dynamic Programming (DP) is combined with a reactive control algorithm. The DP allows the UAVs to navigate among known static barriers and obstacles. Additionally, the reactive controller uses data from the onboard sensor to avoid unforeseen obstacles. The proposed strategy is illustrated through computer simulation results. In simulations, the UAV successfully navigates around dynamic obstacles while maintaining its route to the target. These results highlight the ability of our proposed approach to ensure safe and efficient UAV navigation in complex and obstacle-laden environments.

This work presents a new class of algorithms that extend the domain of Navigation Among Movable Obstacles (NAMO) to unknown environments. Efficient real-time algorithms for solving NAMO problems even when no initial environment information is available to the robot are presented and validated. The algorithms yield optimal solutions and are evaluated for real-time performance on a series of simulated domains with more than 70 obstacles. In contrast to previous NAMO algorithms that required a pre-specified environment model, this work considers the realistic domain where the robot is limited by its sensor range. It must navigate to a goal position in an environment of static and movable objects. The robot can move objects if the goal cannot be reached or if moving the object significantly shortens the path. The robot gains information about the world by bringing distant objects into its sensor range. The first practical planner for this exponentially complex domain is presented. The planner reduces the search-space through a collection of techniques, such as upper bound calculations and the maintenance of sorted lists with underestimates. Further, the algorithm is only considering manipulation actions if these actions are creating a new opening in the environment. In the addition to the evaluation of the planner itself is each of this techniques also validated independently.

Dans cette thèse, nous abordons la navigation autonome d'un robot mobile en milieu domiciliaire congestionné. Cette problématique relève du domaine de la navigation parmi les obstacles amovibles. Nous proposons une architecture robotique permettant la navigation parmi des obstacles fixes, amovibles et interactifs. L'objectif du robot est de rejoindre une position, tout en évitant les obstacles fixes, déplacer les obstacles amovibles s'ils gênent le passage ou bien demander à des obstacles interactifs (humain, robots, etc.) de céder le passage.Dans notre première contribution, nous proposons une architecture robotique hiérarchique baptisée VICA (VIcarious Cognitive Architecture), dont le niveau décisionnel est couplé à une architecture cognitive. Nous nous sommes inspiré des travaux sur la simplixité de Alain Berthoz qui décrivent comment le vivant prépare l'action et anticipe les réactions. L'architecture robotique se compose d'un planificateur global permettant la navigation dans un environnement inconnu et d'un planificateur local dédié à la gestion des obstacles.La seconde met en œuvre un planificateur global dont le but est de rapprocher autant que possible le robot de son objectif, en utilisant l’algorithme H* que nous avons développé.La troisième propose un planificateur local pour la gestion des obstacles. La solution proposée consiste à utiliser la simulation multi-agents dans le but d'anticiper le comportement des obstacles.L'implémentation de cette solution est réalisée dans l'architecture VICA développée sous ROS (Robot Operating System). En parallèle, nous avons développé un robot expérimental pour valider nos résultats
In this thesis, we address the autonomous navigation of a mobile robot in a congested indoor environment. This problem is related to navigation among movable obstacles (NAMO). We propose a robotic architecture allowing navigation among: fixed, removable and interactive obstacles. The objective of the robot is to reach a position, while avoiding fixed obstacles, to move removable obstacles if they obstruct the path or to ask interactive obstacles (human, robots, etc.) to give way.In our first contribution, we propose a hierarchical robotic architecture named VICA (VIcarious Cognitive Architecture), whose decisional level is coupled to a cognitive architecture. We are inspired by Alain Berthoz's work on simplexity, which describes how living organisms prepare actions and anticipate reactions. The robotic architecture is composed of a global planner allowing navigation in an unknown environment and a local planner dedicated to obstacle management.The second one implements a global planner whose goal is to bring the robot as close as possible to its goal, using the H* algorithm we have developed.The third one proposes a local planner for obstacle management. The proposed solution consists in using multi-agent simulation in order to anticipate the behavior of obstacles.The implementation of this solution is realized in the VICA architecture developed under ROS (Robot Operating System). In parallel, we have developed an experimental robot to validate our results

A robot should be able to autonomously modify and utilize its environment to assist its task completion. While mobile manipulators and humanoid robots have both locomotion and manipulation capabilities, planning systems typically just consider one or the other. In traditional motion planning the planner attempts to find a collision free path from the robot's current configuration to some goal configuration. In general, this process entirely ignores the fact that the robot has manipulation capabilities. This is in contrast to how humans naturally act - utilizing their manipulation capabilities to modify the environment to assist locomotion. If necessary, humans do not hesitate to move objects, such as chairs, out of their way or even place an object, such as a board, on the ground to reach an otherwise unreachable goal. We argue that robots should demonstrate similar behavior. Robots should use their manipulation capabilities to move or even use environment objects. This thesis aims at bringing robots closer to such capabilities. There are two primary challenges in developing practical systems that allow a real robotic system to tightly couple its manipulation and locomotion capabilities: the inevitable inaccuracies in perception as well as actuation that occur on physical systems, and the exponential size of the search space. To address these challenges, this thesis first extends the previously introduced domain of Navigation Among Movable Obstacles (NAMO), which allows a robot to move obstacles out of its way. We extend the NAMO domain to handle the underlying issue of uncertainty. In fact, this thesis introduces the first NAMO framework that allows a real robotic systems to consider sensing and action uncertainties while reasoning about moving objects out of the way. However, the NAMO domain itself has the shortcoming that it only considers a robot's manipulation capabilities in the context of clearing a path. This thesis therefore also generalizes the NAMO domain itself to the Navigation Using Manipulable Obstacles (NUMO) domain. The NUMO domain enables a robot to more generally consider the coupling between manipulation and locomotion capabilities and supports reasoning about using objects in the environment. This thesis shows the relationship between the NAMO and NUMO domain, both in terms of complexity as well as solution approaches, and presents multiple realizations of the NUMO domain. The first NUMO realization enables a robot to use its manipulation capabilities to assist its locomotion by changing the geometry of the environment for scenarios in which obstructions can be overcome through the usage of a single object. The system led a real humanoid robot to autonomously build itself a bridge to cross a gap and a stair step to get on a platform. A second NUMO realization then introduces reasoning about force constraints using knowledge about the mechanical advantages of a lever and battering ram. The discussed system allows a robot to consider increasing its effective force though the use of objects, such as utilizing a rod as a lever. Finally this thesis extends the NUMO framework for geometric constraints to scenarios in which the robot is faced with a substantial lack of initial state information and only has access to onboard sensing. In summary, this thesis enables robots to autonomously modify their environment to achieve task completion in the presence of lack of support for mobility, the need to increase force capabilities and partial knowledge.

This research work presents a novel Cognitive Task Planning framework for Smart Industrial Robots. The framework makes an industrial mobile manipulator robot Cognitive by applying Semantic Web Technologies. It also introduces a novel Navigation Among Movable Obstacles algorithm for robots navigating and manipulating inside a firm. The objective of Industrie 4.0 is the creation of Smart Factories: modular firms provided with cyber-physical systems able to strong customize products under the condition of highly flexible mass-production. Such systems should real-time communicate and cooperate with each other and with humans via the Internet of Things. They should intelligently adapt to the changing surroundings and autonomously navigate inside a firm while moving obstacles that occlude free paths, even if seen for the first time. At the end, in order to accomplish all these tasks while being efficient, they should learn from their actions and from that of other agents. Most of existing industrial mobile robots navigate along pre-generated trajectories. They follow ectrified wires embedded in the ground or lines painted on th efloor. When there is no expectation of environment changes and cycle times are critical, this planning is functional. When workspaces and tasks change frequently, it is better to plan dynamically: robots should autonomously navigate without relying on modifications of their environments. Consider the human behavior: humans reason about the environment and consider the possibility of moving obstacles if a certain goal cannot be reached or if moving objects may significantly shorten the path to it. This problem is named Navigation Among Movable Obstacles and is mostly known in rescue robotics. This work transposes the problem on an industrial scenario and tries to deal with its two challenges: the high dimensionality of the state space and the treatment of uncertainty. The proposed NAMO algorithm aims to focus exploration on less explored areas. For this reason it extends the Kinodynamic Motion Planning by Interior-Exterior Cell Exploration algorithm. The extension does not impose obstacles avoidance: it assigns an importance to each cell by combining the efforts necessary to reach it and that needed to free it from obstacles. The obtained algorithm is scalable because of its independence from the size of the map and from the number, shape, and pose of obstacles. It does not impose restrictions on actions to be performed: the robot can both push and grasp every object. Currently, the algorithm assumes full world knowledge but the environment is reconfigurable and the algorithm can be easily extended in order to solve NAMO problems in unknown environments. The algorithm handles sensor feedbacks and corrects uncertainties. Usually Robotics separates Motion Planning and Manipulation problems. NAMO forces their combined processing by introducing the need of manipulating multiple objects, often unknown, while navigating. Adopting standard precomputed grasps is not sufficient to deal with the big amount of existing different objects. A Semantic Knowledge Framework is proposed in support of the proposed algorithm by giving robots the ability to learn to manipulate objects and disseminate the information gained during the fulfillment of tasks. The Framework is composed by an Ontology and an Engine. The Ontology extends the IEEE Standard Ontologies for Robotics and Automation and contains descriptions of learned manipulation tasks and detected objects. It is accessible from any robot connected to the Cloud. It can be considered a data store for the efficient and reliable execution of repetitive tasks; and a Web-based repository for the exchange of information between robots and for the speed up of the learning phase. No other manipulation ontology exists respecting the IEEE Standard and, regardless the standard, the proposed ontology differs from the existing ones because of the type of features saved and the efficient way in which they can be accessed: through a super fast Cascade Hashing algorithm. The Engine lets compute and store the manipulation actions when not present in the Ontology. It is based on Reinforcement Learning techniques that avoid massive trainings on large-scale databases and favors human-robot interactions. The overall system is flexible and easily adaptable to different robots operating in different industrial environments. It is characterized by a modular structure where each software block is completely reusable. Every block is based on the open-source Robot Operating System. Not all industrial robot controllers are designed to be ROS-compliant. This thesis presents the method adopted during this research in order to Open Industrial Robot Controllers and create a ROS-Industrial interface for them.
Questa ricerca presenta una nuova struttura di Pianificazione Cognitiva delle Attività ideata per Robot Industriali Intelligenti. La struttura rende Cognitivo un manipolatore industriale mobile applicando le tecnologie offerte dal Web Semantico. Viene inoltre introdotto un nuovo algoritmo di Navigazione tra Oggetti Removibili per robot che navigano e manipolano all’interno di una fabbrica. L’obiettivo di Industria 4.0 è quello di creare Fabbriche Intelligenti: fabbriche modulari dotate di sistemi cyber-fisici in grado di customizzare i prodotti pur mantenendo una produzione di massa altamente flessibile. Tali sistemi devono essere in grado di comunicare e cooperare tra loro e con gli agenti umani in tempo reale, attraverso l’Internet delle Cose. Devono sapersi autonomamente ed intelligentemente adattare ai costanti cambiamenti dell’ambiente che li circonda. Devono saper navigare autonomamente all’interno della fabbrica, anche spostando ostacoli che occludono percorsi liberi, ed essere in grado di manipolare questi oggetti anche se visti per la prima volta. Devono essere in grado di imparare dalle loro azioni e da quelle eseguite da altri agenti. La maggior parte dei robot industriali mobili naviga secondo traiettorie generate a priori. Seguono filielettrificatiincorporatinelterrenoolineedipintesulpavimento. Pianificareapriorièfunzionale se l’ambiente è immutevole e i cicli produttivi sono caratterizzati da criticità temporali. E’ preferibile adottare una pianificazione dinamica se, invece, l’area di lavoro ed i compiti assegnati cambiano frequentemente: i robot devono saper navigare autonomamente senza tener conto dei cambiamenti circostanti. Si consideri il comportamento umano: l’uomo ragiona sulla possibilità di spostare ostacolise unaposizione obiettivo nonè raggiungibileose talespostamento puòaccorciare la traiettoria da percorrere. Questo problema viene detto Navigazione tra Oggetti Removibili ed è noto alla robotica di soccorso. Questo lavoro traspone il problema in uno scenario industriale e prova ad affrontare i suoi due obiettivi principali: l’elevata dimensione dello spazio di ricerca ed il trattamento dell’incertezza. L’algoritmo proposto vuole dare priorità di esplorazione alle aree meno esplorate, per questo estende l’algoritmo noto come Kinodynamic Motion Planning by Interior-Exterior Cell Exploration. L’estensione non impone l’elusione degli ostacoli. Assegna ad ogni cella un’importanza che combina lo sforzo necessario per raggiungerla con quello necessario per liberarla da eventuali ostacoli. L’algoritmo risultante è scalabile grazie alla sua indipendenza dalla dimensione della mappa e dal numero, forma e posizione degli ostacoli. Non impone restrizioni sulle azioni da eseguire: ogni oggetto può venir spinto o afferrato. Allo stato attuale, l’algoritmo assume una completa conoscenza del mondo circonstante. L’ambiente è però riconfigurabile di modo che l’algoritmo possa venir facilmente esteso alla risoluzione di problemi di Navigazione tra Oggetti Removibili in ambienti ignoti. L’algoritmo gestisce i feedback dati dai sensori per correggere le incertezze. Solitamente la Robotica separa la risoluzione dei problemi di pianificazione del movimento da quelli di manipolazione. La Navigazione tra Ostacoli Removibili forza il loro trattamento combinato introducendo la necessità di manipolare oggetti diversi, spesso ignoti, durante la navigazione. Adottare prese pre calcolate non fa fronte alla grande quantità e diversità di oggetti esistenti. Questa tesi propone un Framework di Conoscenza Semantica a supporto dell’algoritmo sopra esposto. Essodàairobotlacapacitàdiimparareamanipolareoggettiedisseminareleinformazioni acquisite durante il compimento dei compiti assegnati. Il Framework si compone di un’Ontologia e di un Engine. L’Ontologia estende lo Standard IEEE formulato per Ontologie per la Robotica e l’Automazione andando a definire le manipolazioni apprese e gli oggetti rilevati. È accessibile a qualsiasi robot connesso al Cloud. Può venir considerato I) una raccolta di dati per l’esecuzione efficiente ed affidabile di azioni ripetute; II) un archivio Web per lo scambio di informazioni tra robot e la velocizzazione della fase di apprendimento. Ad ora, non esistono altre ontologie sulla manipolazione che rispettino lo Standard IEEE. Indipendentemente dallo standard, l’Ontologia propostadifferiscedaquelleesistentiperiltipodiinformazionisalvateeperilmodoefficienteincui un agente può accedere a queste informazioni: attraverso un algoritmo di Cascade Hashing molto veloce. L’Engine consente il calcolo e il salvataggio delle manipolazioni non ancora in Ontologia. Si basa su tecniche di Reinforcement Learning che evitano il training massivo su basi di dati a larga scala, favorendo l’interazione uomo-robot. Infatti, viene data ai robot la possibilità di imparare dagli umani attraverso un framework di Apprendimento Robotico da Dimostrazioni. Il sistema finale è flessibile ed adattabile a robot diversi operanti in diversi ambienti industriali. È caratterizzato da una struttura modulare in cui ogni blocco è completamente riutilizzabile. Ogni blocco si basa sul sistema open-source denominato Robot Operating System. Non tutti i controllori industriali sono disegnati per essere compatibili con questa piattaforma. Viene quindi presentato il metodo che è stato adottato per aprire i controllori dei robot industriali e crearne un’interfaccia ROS.

碩士
大同工學院
電機工程研究所
87
In this thesis, we will integrate the method of the path planning and trajectory tracking control to develop a navigation strategy for the car-like mobile robot among the irregular obstacles in the planar space. The navigation strategy comprises two phases. During the first phase, the local path planning generates an immediate goal position and collision-free reference trajectory. During the second phase, the security strategy of the trajectory tracking method generates a safe goal position and new reference trajectory corresponding to the planned immediate goal position at first. Then, the robot will track this new reference trajectory by a trajectory tracking fuzzy logic controller and arrive at the safe goal position. After the robot arrives at the safe goal position, the safe goal position will be exchanged as the new starting position corresponding to the next path planning. This process will be repeated until the robot arrives at the final goal position. There are some advantages in this navigation strategy: (i) The local path planning generates the reference trajectories simply and quickly. (ii) The trajectory tracking fuzzy logic controller provides an efficient trajectory tracking control for the car-like mobile robot. (iii) The navigation strategy guarantees that it can bring a car-like mobile robot to a desired position without hitting irregular convex or concave polygonal obstacles in the planar space.

AbstractAs autonomous vehicles become increasingly prevalent in our daily lives, new control challenges arise to ensure their safety and the safety of their surroundings. This work addresses these challenges by developing a suitable regulator that strikes a balance between different objectives. The first one is ‘safety’, which involves satisfying constraints and consistently avoiding obstacles. The second objective is ‘exploitation’, which aims to optimize the utilization of existing knowledge about the environment, reducing the overly cautious behaviour of guaranteed collision-free approaches. The third objective is ‘exploration’, which pertains to the ability to discover potential unknown areas while avoiding getting stuck in blocked regions. The design of motion planning algorithms for such systems requires carefully managing the trade-off between these requirements. Among the various approaches to dynamic path planning, discrete optimization methods such as Model Predictive Control (MPC) have gained significant attention. MPC excels in handling state and input constraints to ensure safety while minimizing a cost function defined by the user, enabling both exploitation and exploration aspects. By developing a suitable regulator and leveraging MPC approaches, this work aims to address the complex control challenges faced by autonomous vehicles and other safety-critical applications, ensuring a balance between safety, exploitation, and exploration.