Laboratoire d’analyse et d’architecture des systèmes
V.ARELLANO, E.A.MERCHAN-CRUZ, A.FRANCHI
IPN Mexique, RIS
Revue Scientifique : IEEE Access, pp.68155-68168, Décembre 2018 , N° 18427
This paper proposes a new mathematical model to map the rotational speed and angle of attack (pitch) of small-size propellers typically used in multirotors and the aerodynamic thrust force and drag moment produced by the propeller itself. The new model is inspired by standard models using the blade-element and momentum theories, which have been suitably modified in order to allow for explicit fast computation of the direct and inverse map (useful for high-frequency control) and obtain a better adherence to experimental data. The new model allows and captures all the main nonlinear characteristics of the thrust/drag generation. An extensive experimental comparison shows that the prediction capability of the proposed model outperforms the most commonly used models at date. In the second part of the paper, two optimization methods are proposed in order to exploit the redundancy of the inputs of variable-pitch propellers to decrease the power consumption due to the drag dissipation. The first method deals with the optimal allocation for thrust generation on a single propeller, while the second method is aimed at solving the optimal allocation of the rotational speed and pitch of all the propellers in a multi-rotor with any number of propellers. Simulations results show the viability and effectiveness of the proposed methods
N.STAUB, M.MOHAMMADI, D.BICEGO, Q.DELAMARE, H.YANG, D.PRATTICHIZZO, P.R.GIORDANO, D.LEE, A.FRANCHI
RIS, University of Siena, IRISA, Seoul, IIT, Genova, INRIA Rennes
Revue Scientifique : IEEE Robotics and Automation Magazine, 10p., Décembre 2018, DOI 10.1109/MRA.2018.2871344 , N° 18417
A.CLODIC, J.VAZQUEZ-SALCEDA, F.DIGNUM, S.MASCARENHAS, V.DIGNUM, A.AUGELLO, M.GENTILE, R.ALAMI
IDEA, UPC, Utrecht, INESC, Delft, CNR, RIS
Ouvrage (contribution) : Envisioning Robots in Society – Power, Politics, and Public Space, IOS Press, N°ISBN 978-1-61499-931-7, Décembre 2018, pp.63-74 , N° 18438
In the area of consumer robots that need to have rich social interactions with humans, one of the challenges is the complexity of computing the appropriate interactions in a cognitive, social and physical context. We propose a novel approach for social robots based on the concept of Social Practices. By using social practices robots are able to be aware of their own social identities (given by the role in the social practice) and the identities of others and also be able to identify the different social contexts and the appropriate social interactions that go along with those contexts and identities.
C.GABELLIERI, M.TOGNON, L.PALLOTTINO, A.FRANCHI
Manifestation avec acte : International Conference on Swarm Intelligence ( ANTS ) 2018 du 29 octobre au 31 octobre 2018, Rome (Italie), Novembre 2018, 13p. , N° 18263
This work investigates collaborative aerial transportation by swarms of agents based only on implicit information, enabled by the physical interaction among the agents and the environment. Such a coordinating mechanism in collaborative transportation is a basic skill in groups of social animals. We consider cable-suspended objects transported by a swarm of flying robots and we formulate several hypothesis on the behavior of the overall system which are validated thorough numerical study. In particular, we show that a nonzero internal force reduces to one the number of asymptotically stable equilibria and that the internal force intensity is directly connected to the convergence rate. As such, the internal force represents the cornerstone of a communication-less cooperative manipulation paradigm in swarms of flying robots. We also show how a swarm can achieve a stable transportation despite the imprecise knowledge of the system parameters.
M.TOGNON, H.TELLO CHAVEZ, E.GASPARIN, Q.SABLE, D.BICEGO, A.MALLET, M.LANY, G.SANTI, B.REVAZ, J.CORTES, A.FRANCHI
RIS, Sensima Inspection, IDEA
Rapport LAAS N°18353, Novembre 2018, 9p.
We present the design, control and motion planning of an aerial manipulator for a non-trivial physical interaction task, namely pushing while sliding on curved surfaces. The proposed robotic system is motivated by the increasing interest on autonomous Non-Destructive Tests used for the integrity assessment of industrial plants. The proposed aerial manipulator consists of a multidirectional-thrust aerial vehicle to enhance physical interaction capabilities, endowed with a 2-DoFs lightweight arm to enlarge its workspace. This combination constitutes a truly redundant manipulator that goes beyond standard aerial manipulators with collinear multirotors. The robot controller is based on a PID method with 'displaced' positional part inspired by controllers for manipulators with elastic joints and grounded on several experimental trial-and-error tests. In this work we experimentally show that the proposed aerial manipulator system, equipped with an Eddy Current probe, is able to scan a metallic pipe sliding the sensor over its surface and preserving the contact. From the acquired data, a weld on the pipe is successfully detected and mapped.
Revue Scientifique : International Journal of Robotics and Automation, Vol.33, N°6, Novembre 2018 , N° 18532
This paper aims to propose an on-line trajectory generation algorithm that is able to address not only constant but also time-variant kinematic motion constraints for multi-DOFs robot manipulators. By using a concatenation of cubic polynomials, the proposed method can provide a smooth trajectory that is synchronized and bounded in the robot kinematic motion constraints which are expressed as upper bounds on the absolute values of velocity, acceleration, and jerk. An additional decision tree will select intermediate motion proﬁles when the motion constraints are abruptly changed. Due to direct computation without optimization computation or randomized algorithms, the proposed solution requires only a short execution time. Simulations and experiments were conducted to verify the feasibility and eﬀectiveness of this algorithm in smooth trajectory generation from arbitrary states of motion. With the proposed approach, robot motion can be limited by the kinematic motion constraints which will reduce manipulator wear and improve tracking accuracy and speed. The proposed algorithm can be used in real time due to the low computational complexity.
A.CHARPENTIER, D.MIGNON, S.BARBE, J.CORTES, T.SCHIEX, T.SIMONSON, D.ALLOUCHE
Atos Origin, BIOC, LISBP, RIS, INRA Castanet
Revue Scientifique : Journal of Chemical Information and Modeling, Octobre 2018 , N° 18439
Computational protein design (CPD) aims to predict amino acid sequences that fold to specific structures and perform desired functions. CPD depends on a rotamer library, an energy function, and an algorithm to search the sequence/conformation space. Variable neighborhood search (VNS) with cost function networks is a powerful framework that can provide tight upper bounds on the global minimum energy. We propose a new CPD heuristic based on VNS in which a subset of the solution space (a “neighborhood”) is explored, whose size is gradually increased with a dedicated probabilistic heuristic. The algorithm was tested on 99 protein designs with fixed backbones involving nine proteins from the SH2, SH3, and PDZ families. The number of mutating positions was 20, 30, or all of the amino acids, while the rest of the protein explored side-chain rotamers. VNS was more successful than Monte Carlo (MC), replica-exchange MC, and a heuristic steepest-descent energy minimization, providing solutions with equal or lower best energies in most cases. For complete protein redesign, it gave solutions that were 2.5 to 11.2 kcal/mol lower in energy than those obtained with the other approaches. VNS is implemented in the toulbar2 software. It could be very helpful for large and/or complex design problems.
M.JUSOT, D.STRATMANN, M.VAISSET, J.CHOMILIER, J.CORTES
RIS, IMPMC, IDEA
Revue Scientifique : Journal of Chemical Information and Modeling, 42p., Octobre 2018, DOI: 10.1021/acs.jcim.8b00375 , N° 18324
Small cyclic peptides represent a promising class of therapeutic molecules with unique chemical properties. However, the poor knowledge of their structural characteristics makes their computational design and structure prediction a real challenge. In order to better describe their conformational space, we developed a method, named EGSCyP, for the exhaustive exploration of the energy landscape of small head-to-tail cyclic peptides. The method can be summarized by (i) a global exploration of the conformational space based on a mechanistic representation of the peptide and the use of robotics-based algorithms to deal with the closure constraint, (ii) an all-atom refinement of the obtained conformations. EGSCyP can handle D-form residues and N-methylations. Two strategies for the side-chains placement were implemented and compared. To validate our approach, we applied it to a set of three variants of cyclic RGDFV pentapeptides, including the drug candidate Cilengitide. A comparative 1 analysis was made with respect to replica exchange molecular dynamics simulations in implicit solvent. It results that the EGSCyP method provides a very complete characterization of the conformational space of small cyclic pentapeptides.
C.MASONE, M.MOHAMMADI, P.R.GIORDANO, A.FRANCHI
Max Planck, IIT, Genova, INRIA Rennes, RIS
Revue Scientifique : International Journal of Robotics Research, 27p., Octobre 2018, doi 10.1177/0278364918802006 , N° 18304
This paper presents a novel bilateral shared framework for online trajectory generation for mobile robots. The robot navigates along a dynamic path, represented as a B-spline, whose parameters are jointly controlled by a human supervisor and by an autonomous algorithm. The human steers the reference (ideal) path by acting on the path parameters which are also affected, at the same time, by the autonomous algorithm in order to ensure: i) collision avoidance, ii) path regularity and iii) proximity to some points of interest. These goals are achieved by combining a gradient descent-like control action with an automatic algorithm that re-initializes the traveled path (replanning) in cluttered environments in order to mitigate the effects of local minima. The control actions of both the human and the autonomous algorithm are fused via a filter that preserves a set of local geometrical properties of the path in order to ease the tracking task of the mobile robot. The bilateral component of the interaction is implemented via a force feedback that accounts for both human and autonomous control actions along the whole path, thus providing information about the mismatch between the reference and traveled path in an integral sense. The proposed framework is validated by means of realistic simulations and actual experiments deploying a quadrotor UAV supervised by a human operator acting via a force-feedback haptic interface. Finally, a user study is presented in order to validate the effectiveness of the proposed framework and the usefulness of the provided force cues.
A.OLLERO, G.HEREDIA, A.FRANCHI, G.ANTONELLI, K.KONDAC, A.S.CORTES, A.VIGURIA, J.R.MARTINEZ-DE-DIOS, F.PIERRI, J.CORTES, A.SANTAMARIA-NAVARRO, M.A.TRUJILLO SOTO, R.BALACHANDRAN, J.ANDRADE-CETTO, A.RODRIGUEZ CASTANO
Seville, RIS, UNICAS, DLR, UPC, CATEC, University of Basilicata, IRI, UPC/CSIC
Revue Scientifique : IEEE Robotics and Automation Magazine, 9p., Octobre 2018, DOI: 10.1109/MRA.2018.2852789 , N° 18297
This paper summarizes new aerial robotic manipulation technologies and methods, required for outdoor industrial inspection and maintenance, developed in the AEROARMS project. It presents aerial robotic manipulators with dual arms and multi-directional thrusters. It deals with the control systems, including the control of the interaction forces and the compliance, the teleoperation, which uses passivity to tackle the trade-off between stability and performance, perception methods for localization, mapping and inspection, and planning methods, including a new control-aware approach for aerial manipulation. Finally, it describes a novel industrial platform with multi-directional thrusters and a new arm design to increase the robustness in industrial contact inspections. The lessons learned in the application to outdoor aerial manipulation for inspection and maintenance are pointed out.