Fitting primitive shapes in point clouds: a practical approach to improve autonomous underwater grasp specification of unknown objects

This article presents research on the subject of autonomous underwater robot manipulation. Ongoing research in underwater robotics intends to increase the autonomy of intervention operations that require physical interaction in order to achieve social benefits in fields such as archaeology or biology that cannot afford the expenses of costly underwater operations using remote operated vehicles. Autonomous grasping is still a very challenging skill, especially in underwater environments, with highly unstructured scenarios, limited availability of sensors and adverse conditions that affect the robot perception and control systems. To tackle these issues, we propose the use of vision and segmentation techniques that aim to improve the specification of grasping operations on underwater primitive shaped objects. Several sources of stereo information are used to gather 3D information in order to obtain a model of the object. Using a RANSAC segmentation algorithm, the model parameters are estimated and a set of feasible grasps are computed. This approach is validated in both simulated and real underwater scenarios.This research was partly supported by Spanish Ministry of Research and Innovation DPI2011-27977-C03 (TRITON Project), by Foundation Caixa Castelló Bancaixa PI-1B2011-17, by Universitat Jaume I PhD grants PREDOC/2012/47 and PREDOC/ 2013/46, and by Generalitat Valenciana PhD grant ACIF/2014/298

I-AUV Docking and Panel Intervention at Sea

The use of commercially available autonomous underwater vehicles (AUVs) has increased during the last fifteen years. While they are mainly used for routine survey missions, there is a set of applications that nowadays can be only addressed by manned submersibles or work-class remotely operated vehicles (ROVs) equipped with teleoperated arms: the intervention applications. To allow these heavy vehicles controlled by human operators to perform intervention tasks, underwater structures like observatory facilities, subsea panels or oil-well Christmas trees have been adapted, making them more robust and easier to operate. The TRITON Spanish founded project proposes the use of a light-weight intervention AUV (I-AUV) to carry out intervention applications simplifying the adaptation of these underwater structures and drastically reducing the operational cost. To prove this concept, the Girona 500 I-AUV is used to autonomously dock into an adapted subsea panel and once docked perform an intervention composed of turning a valve and plugging in/unplugging a connector. The techniques used for the autonomous docking and manipulation as well as the design of an adapted subsea panel with a funnel-based docking system are presented in this article together with the results achieved in a water tank and at sea.This work was supported by the Spanish project DPI2014-57746-C3 (MERBOTS Project) and by Generalitat Valenciana under Grant GVA-PROMETEO/2016/066. The University of Girona wants to thank the SARTI group for their collaboration with the TRITON project

I-AUV Docking and Panel Intervention at Sea

The use of commercially available autonomous underwater vehicles (AUVs) has increased during the last fifteen years. While they are mainly used for routine survey missions, there is a set of applications that nowadays can be only addressed by manned submersibles or work-class remotely operated vehicles (ROVs) equipped with teleoperated arms: the intervention applications. To allow these heavy vehicles controlled by human operators to perform intervention tasks, underwater structures like observatory facilities, subsea panels or oil-well Christmas trees have been adapted, making them more robust and easier to operate. The TRITON Spanish founded project proposes the use of a light-weight intervention AUV (I-AUV) to carry out intervention applications simplifying the adaptation of these underwater structures and drastically reducing the operational cost. To prove this concept, the Girona 500 I-AUV is used to autonomously dock into an adapted subsea panel and once docked perform an intervention composed of turning a valve and plugging in/unplugging a connector. The techniques used for the autonomous docking and manipulation as well as the design of an adapted subsea panel with a funnel-based docking system are presented in this article together with the results achieved in a water tank and at sea.This work was supported by the Spanish project DPI2014-57746-C3 (MERBOTS Project) and by Generalitat Valenciana under Grant GVA-PROMETEO/2016/066. The University of Girona wants to thank the SARTI group for their collaboration with the TRITON project

Visually-Guided Manipulation Techniques for Robotic Autonomous Underwater Panel Interventions

The long term of this ongoing research has to do with increasing the autonomy levels for underwater intervention missions. Bearing in mind that the speci c mission to face has been the intervention on a panel, in this paper some results in di erent development stages are presented by using the real mechatronics and the panel mockup. Furthermore, some details are highlighted describing two methodologies implemented for the required visually-guided manipulation algorithms, and also a roadmap explaining the di erent testbeds used for experimental validation, in increasing complexity order, are presented. It is worth mentioning that the aforementioned results would be impossible without previous generated know-how for both, the complete developed mechatronics for the autonomous underwater vehicle for intervention, and the required 3D simulation tool. In summary, thanks to the implemented approach, the intervention system is able to control the way in which the gripper approximates and manipulates the two panel devices (i.e. a valve and a connector) in autonomous manner and, results in di erent scenarios demonstrate the reliability and feasibility of this autonomous intervention system in water tank and pool conditions.This work was partly supported by Spanish Ministry of Research and Innovation DPI2011-27977-C03 (TRITON Project) and DPI2014-57746-C3 (MERBOTS Project), by Foundation Caixa Castell o-Bancaixa and Universitat Jaume I grant PID2010-12, by Universitat Jaume I PhD grants PREDOC/2012/47 and PREDOC/2013/46, and by Generalitat Valenciana PhD grant ACIF/2014/298. We would like also to acknowledge the support of our partners inside the Spanish Coordinated Projects TRITON and MERBOTS: Universitat de les Illes Balears, UIB (subprojects VISUAL2 and SUPERION) and Universitat de Girona, UdG (subprojects COMAROB and ARCHROV)

Framework for Autonomous Underwater Grasping of Unknown Objects

This thesis studies the problem of autonomously grasping an unknown object in an underwater scenario using an I-AUV. Firstly, a new approach to autonomously obtain an accurate and complete 3D reconstruction of an object of interest is presented. Next, it is detailed an algorithm to control redundant kinematics having into account hard constraints. Then, an algorithm to calculate the pose of the gripper that fulfill, in a grater way, a hierarchy of tasks and that strictly accomplishes a set of constraints. The following proposed methodology guides the gripper to the planned pose avoiding collisions. Finally, two methodologies for avoiding problems during the intervention and fix them are explained. The first controls the position and orientation of the arm end-effector. The second detects contacts between the gripper and the environment, and correct the end-effector trajectory to avoid them.Esta tesis estudia el problema de agarrar un objeto desconocido en un entorno subacuático de forma autónoma utilizando un I-AUV. Primeramente, presenta una aproximación para obtener una reconstrucción 3D precisa y completa de forma autónoma de un objeto de interés. Seguidamente, detalla un algoritmo para controlar cinemáticas redundantes teniendo en cuenta restricciones. A continuación, explica un algoritmo que calcula la posición y orientación de la garra que cumpla, en mayor medida, un conjunto de tareas ordenadas por prioridad y que estrictamente cumpla una serie de restricciones. La siguiente metodología propuesta, guía la garra hasta la posición planificada evitando colisiones. Finalmente, explica dos metodologías para detectar problemas durante la intervención y corregirlos. La primera controla la posición y orientación alcanzados por el efector final del brazo. La segunda, detecta contactos entre la garra y el entorno, y corrige la trayectoria del efector final para evitarlos.Programa de Doctorat en Informàtic

Autonomous underwater grasping using multi-view laser reconstruction

Comunicació presentada a Oceans 2017 Conference, Aberdeen, 19-22 June 2017Autonomous manipulation in underwater scenarios is a highly complex task which is still poorly studied, but with a growing interest in the last years. Two of the main phases of this problem are the detection and characterization of the object which is going to be manipulated, and the planning of this manipulation. This paper presents, on the one hand, the results of a multi-view laser reconstruction approach used in a real system. This approach consists in attaching a laser emitter and a camera in the forearm of a robotic arm. Then, moving the arm, the scene is scanned and reconstructed. This configuration allows the user to reconstruct autonomously a scene from different points of view and with a high precision. On the other hand, a grasp planning algorithm has been described. This method makes possible to autonomously detect the object of interest from a scene with multiple objects, and to choose which is the best arm configuration in order to manipulate it

Exploring 3-D Reconstruction Techniques: A Benchmarking Tool for Underwater Robotics

When the results of research in the field of robotics are presented to the scientific community, the same question is asked repeatedly: Are the results really reproducible? Regarding benchmarking issues, some technological areas where complex mechatronic devices, such as robots, have a central role are very far from other research areas like physics or chemistry, to name but a few, where reproducibility is always mandatory. Aside from mechatronic complexities, the comparison between two different algorithms in the same conditions is influenced by the experimental validation scenario. In underwater environments, the difficulties for benchmarking characterization increase substantially. This is especially true when the test bed is the sea where uncertainty is high. It is the aim of this article to present a software tool which enables a comparison between two different algorithms when the algorithms are being used to solve the same problem in water tank conditions. This is a preliminary stage before the final validation on the seabed. The evaluated algorithms fall into the three-dimensional (3-D) image reconstruction context, as a prior step to their autonomous manipulation. Performance results are presented for both simulation and real water tank conditions