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ETFA'15: Task and Motion Planning Using Physics-based Reasoning

Aliakbar Akbari, Muhayyuddin and Jan Rosell
Proceedings of the 20th IEEE International Conference on Emerging Technologies and Factory Automation, ETFA'15, ISBN 978-1-4673-7928-1, City of Luxembourg, Luxembourg, September 08-11, 2015.

Abstract: For everyday manipulation tasks, the combination of task and motion planning is required regarding the need of providing the set of possible subtasks which have to be done and how to perform them. Since many alternative plans may exist, the determination of their feasibility and the identification of the best one is a great challenge in robotics. To address this, this paper proposes: a) a version of GraphPlan (one of the best current approaches to task planning) that has been modified to use ontological knowledge and to allow the retrieval of all possible plans; and b) a physics-based reasoning process that determines the feasibility of the resulting plans and an associated cost that allows to select the best one among them. The proposed framework has been implemented and is illustrated through an example. For everyday manipulation tasks, the combinationof task and motion planning is required regarding the need ofproviding the set of possible subtasks which have to be doneand how to perform them. Since many alternative plans mayexist, the determination of their feasibility and the identificationof the best one is a great challenge in robotics. To address this,this paper proposes: a) a version of GraphPlan (one of the bestcurrent approaches to task planning) that has been modifiedto use ontological knowledge and to allow the retrieval of allpossible plans; and b) a physics-based reasoning process thatdetermines the feasibility of the resulting plans and an associatedcost that allows to select the best one among them. The proposedframework has been implemented and is illustrated through anexample.

ETFA'15: Ontological Physics-based Motion Planning for Manipulation

Muhayyuddin, Aliakbar Akbari and Jan Rosell
Proceedings of the 20th IEEE International Conference on Emerging Technologies and Factory Automation, ETFA'15, ISBN 978-1-4673-7928-1, City of Luxembourg, Luxembourg, September 08-11, 2015.

Abstract: Robotic manipulation involves actions where contacts occur between the robot and the objects. In this scope, the availability of physics-based engines allows motion planners to comprise dynamics between rigid bodies, which is necessary for planning this type of actions. However, physics-based motion planning is computationally intensive due to the high dimensionality of the state space and the need to work with a low integration step to find accurate solutions. On the other hand, manipulation actions change the environment and conditions further actions and motions. To cope with this issue, the representation of manipulation actions using ontologies enables a semantic-based inference processe that alleviates the computational cost of motion planning. This paper proposes a manipulation planning framework where physics-based motion planning is enhanced with ontological knowledge representation and reasoning. The proposal has been implemented and is illustrated and validated with a simple example. Its use in grasping tasks in cluttered

ICRA'15: Using Synergies in Dual-Arm Manipulation Tasks

Raúl Suárez, Jan Rosell and Néstor García
Proceedings of the IEEE International Conference on Robotics and Automation, (ISBN: 978-1-4799-6922-7), Seattle, Wahington, USA, May 26-30th, 2015.

Abstract: The paper deals with the problem of planning movements of dual-arm anthropomorphic systems, with the aim of reducing the computational cost of the problem and making the movements look as human-like as possible. The key idea of the proposal is the search of synergies of the dualarm anthropomorphic system in order to use them to reduce the dimension of the search space while preserving human-like appearance. This idea was already developed and successfully used to plan movements of robotic hands, thus the extension to a dual-arm system is attractive. The paper presents a description of the proposed approach as well as real experimental results that encourage doing further research in this line.

ETFA'14: cRRT*: Planning loosely-coupled motions for multiple mobile robots

Jan Rosell and Raúl Suárez
Proceedings of the 19th IEEE International Conference on Emerging Technologies and Factory Automation, (ISBN: 978-1-4799-4846-8), Barcelona, Spain, September 16-19th, 2014.

Abstract: The planning of collision-free paths of a team of mobile robots involves many degrees of freedom and therefore the use of sampling-based methods is a good alternative. Among them, the RRT planner has been proposed to cope with optimization problems, and has been proven to be asymptotically optimal. Any optimization function can be defined, although optimization has been usually focused on the traveled distance or on safety, i.e. to find paths of minimum length or maximum clearance. Other constraints to be considered are related to the coordinate movements of the robots, including aspects like keeping a desired formation o having some similar behavior. In this paper we propose the use of an RRT to optimize the traveled distance but subject to a coupled behavior between robots, i.e. it is desired that the robots behave as a group with similar or coordinated movements. To achieve so, a cost function has been defined that evaluates the alignment of the edges of the RRT with the vectors that define the coupling between the motion directions of the robots. The method establishes a compromise between the independence required to avoid obstacles in a flexible way and the desired coupling to behave as a team. The method is illustrated with several examples.

ICRA2012: Motion Planning for the virtual bronchoscopy

Jan Rosell, Alexander Pérez, Paolo Cabras and Antoni Rosell
Proceedings of the 2012 IEEE Int. Conference on Robotics and Automation, ICRA'12, (ISBN CFP12RAA-USB), St. Paul, Minessota, USA, May 14-18, 2012, pp. 2932-2937.

Abstract: Bronchoscopy is an interventional medical procedure employed to analyze the interior side of the human airways, clear possible obstructions and biopsy. Using a 3D reconstruction of the tracheobronchial tree, Virtual Bronchoscopy (VB) may help physicians in the exploration of peripheral lung lesions. We are developing a haptic-based navigation system for the VB that allows the navigation within the airways using a haptic device whose permitted motions mimics those done with the real bronchoscope. This paper describes the motion planning module of the system devoted to plan a path from the trachea to small peripheral pulmonary lesions, that takes into account the geometry and the kinematic constraints of the bronchoscope. The motion planner output is used to visually and haptically guide the navigation during the virtual exploration using the haptic device. Moreover, physicians can get useful information of whether the peripheral lesions can effectively be reached with a given bronchoscope or of which is the nearest point to the lesion that can be reached.

IFAC 2011: Haptic-based navigation for the virtual bronchoscopy

Paolo Cabras, Jan Rosell, Alexander Pérez, Wilbert G. Aguilar, Antoni Rosell
Proceedings of the 18th IFAC World Congress, IFAC 2011, Milan, Italy, August 28-2 Sept 2, 2011, Vol. 18 (1), pp. 9638-9643 ( ISBN: 978-3-902661-93-7)

Abstract: In order to help in the diagnosis of peripheral lung lesions, this paper presents a virtual bronchoscopy system that allows the navigation within a 3D reconstruction of the tracheobronchial tree using a haptic device whose permitted motions mimics those done with the real bronchoscope, and that is able to feedback forces resulting from contacts with the walls. The system reconstructs the 3D model from CT images, and computes a path from the trachea to the peripheral target to be analyzed in order to guide the exploration. The execution of the virtual bronchoscopy with the proposed system, prior to the execution of the real one, may increase the confidence of pulmonologists and is expected to result in an improvement in the final lung cancer diagnosis.

ICRA 2011: An assisted re-synchronization method for robotic teleoperated tasks

Alexander Pérez and Jan Rosell
Proceedings of the 2011 IEEE International Conference on Robotics and Automation, ICRA 2011, (ISBN: 978-1-61284-380-3 ), Shanghai, China, May 9-13, 2011, pp. 886-891

Abstract: Teleoperation tasks are performed at cartesian level when the robot and the haptic device have dissimilar kinematics. If the size of the workspaces is also dissimilar, as it is usually the case, the mapping between workspaces must be handled with care in order to let the user teleoperate the robot in a natural and precise way. This paper formulates the mapping of workspaces based on the re-synchronization method and proposes an assisted system that lightens the user from the tedious part of the method, by guiding him/her towards the best re-synchronization position, thus minimizing the number of jumps. The proposal is part of a teleoperated guiding system being developed by the authors.

ISAM 2011: Including virtual constraints in motion planning for anthropomorphic hands

Jan Rosell, Raúl Suárez, Alexander Pérez and Carlos Rosales
Proceedings of the 2011 IEEE International Symposium on Assembly and Manufacturing, ISAM'11, Tampere Talo, Finland, May 25-27, 2011.

Abstract: This paper copes with the problem of finding a collision-free path for a hand-arm robotic system from an initial unconstrained configuration to a final grasping (or preshape) one. The aim is to obtain a natural motion as a sequence of human-like postures that both capture the coupling that there exist between the fingers of the human hand and also maintain the palm oriented towards the object to be grasped. The proposed method is a sampling-based approach whose efficiency relies in the reduction of the dimensionality obtained by considering, for the finger joints, a subspace determined by the main principal motion directions that capture the coupling and, for the position and orientation of the palm, the submanifold that satisfies the orientation constraint. The approach is illustrated with an example and compared to the case where no virtual constrains are used, validating the proposal.

Autonomous Robots 2011: Autonomous motion planning of a hand-arm robotic system based on human-like hand postures

Jan Rosell, Raúl Suárez, Carlos Rosales and Alexander Pérez
Autonomous Robots: Volume 31, Issue 1 (2011), Page 87-102.

Abstract: The paper deals with the problem of motion planning of anthropomorphic mechanical hands avoiding collisions and trying to mimic real human hand postures. The approach uses the concept of "principal motion directions" to reduce the dimension of the search space in order to obtain results with a compromise between motion optimality and planning complexity (time). Basically, the work includes the following phases: capturing the human hand workspace using a sensorized glove and mapping it to the mechanical hand workspace, reducing the space dimension by looking for the most relevant principal motion directions, and planning the hand movements using a probabilistic roadmap planner. The approach has been implemented for a four finger anthropomorphic mechanical hand (17 joints with 13 independent degrees of freedom) assembled on an industrial robot (6 independent degrees of freedom), and experimental examples are included to illustrate its validity.

IROS 2009: Efficient search of obstacle-free paths for anthropomorphic hands

R. Suárez, J. Rosell, A. Pérez and C. Rosales
Proceedings of the 2009 IEEE/RSJ International Conference on Intelligent Robots and System, IROS'09, (ISBN: 978-1-4244-3804-4), St. Louis, USA, October 11-15, 2009, pp. 1773-1778

Abstract: The planning of collision-free motions of a hand-arm system to reach a grasp or preshape configuration is not a simple issue due to the high number of involved degrees of freedom. This paper presents an efficient sampling-based path planner that copes with this issue by considering a reduced search space. The dimension of this space is not fixed but it is iteratively increased according to the difficulty of the task at hand. Initially the search space is 1-dimensional along the line defined by the initial and goal hand configurations (by construction those configurations always belong to the search space), and then its dimension is increased by iteratively adding principal motion directions (that couple the finger motions), trying in this way to produce hand movements through anthropomorphic natural postures.

ICRA 2009: Motion planning for high DOF anthropomorphic hands

J. Rosell, R. Suárez, C. Rosales, J. A. García and A. Pérez
Proeceedings of the 2009 IEEE International Conference on Robotics and Automation, ICRA 2009, (ISBN: 978-1-4244-2789-5), Kobe, Japan, May 12-17, 2009, pp. 4025-4030

Abstract: The paper deals with the problem of motion planning of anthropomorphic mechanical hands avoiding collisions. The proposed approach tries to mimic the real human hand motions, but reducing the dimension of the search space in order to obtain results as a compromise between motion optimality and planning complexity (time) by means of the concept of principal motion directions. Basically, the work includes the following phases: capturing the human hand workspace using a sensorized glove and mapping it to the mechanical hand workspace, reducing the space dimension by looking for the most relevant principal motion directions, and planning the hand movements using a sampling-based roadmap planner. The approach has been implemented for a four finger anthropomorphic mechanical hand, and some examples are included to illustrate its validity.