The goal of this paper is to increase the estimation performance of an Extended Kalman Filter for a nonlinear differentially flat system by planning trajectories able to maximize the amount of information gathered by onboard sensors in presence of both process and measurement noises. In a previous work, we presented an online gradient descent method for planning optimal trajectories along which the smallest eigenvalue of the Observability Gramian (OG) is maximized. As the smallest eigenvalue of the OG is inversely proportional to the maximum estimation uncertainty, its maximization reduces the maximum estimation uncertainty of any estimation algorithm employed during motion. However, the OG does not consider the process noise that, instead, in several applications is far from being negligible. For this reason, this paper proposes a novel solution able to cope with non-negligible process noise: this is achieved by minimizing the largest eigenvalue of the a posteriori covariance matrix obtained by solving the Continuous Riccati Equation as a measure of the total available information. This minimization is expected to maximize the information gathered by the outputs while, at the same time, limiting as much as possible the negative effects of the process noise. We apply our method to a unicycle robot. The comparison between the novel method and the one of our previous work (which did not consider process noise) shows significant improvements in the obtained estimation accuracy.

%B 2018 IEEE International Conference on Robotics and Automation (ICRA) %P 2118-2125 %8 May %U https://ieeexplore.ieee.org/document/8460476 %R 10.1109/ICRA.2018.8460476 %0 Journal Article %J IEEE Transactions on Robotics (T-RO) %D 2015 %T Epsilon-Optimal Synthesis for Unicycle-like Vehicles with Limited Field-Of-View Sensors %A P Salaris %A A. Cristofaro %A L. Pallottino %K Embedded Control %K Robotics %XIn this paper we study the minimum length paths covered by the center of a unicycle equipped with a limited Field–Of–View (FOV) camera, which must keep a given landmark in sight. Previous works on this subject have provided the optimal synthesis for the cases in which the FOV is only limited in the horizontal directions (i.e. left and right bounds) or in the vertical directions (i.e. upper and lower bounds). In this paper we show how to merge previous results and hence obtaining, for a realistic image plane modeled as a rectangle, a finite alphabet of extremal arcs and the overall synthesis. As shown, this objective can not be straightforwardly achieved from previous results but needs further analysis and developments. Moreover, there are initial configurations such that there exists no optimal path. Nonetheless, we are always able to provide an e–optimal path whose length approximates arbitrarily well any other shorter path. As final results, we provide a partition of the motion plane in regions such that the optimal or e–optimal path from each point in thatregion is univocally determined.

%B IEEE Transactions on Robotics (T-RO) %V 31 %P 1404 - 1418 %G eng %N 6 %R 10.1109/TRO.2015.2492878 %0 Journal Article %J International Journal of Advanced Robotic Systems %D 2013 %T A Complete Observability Analysis of the Planar Bearing Localization and Mapping for Visual Servoing with Known Camera Velocities %A F. A. W. Belo %A P Salaris %A D. Fontanelli %A A. Bicchi %K Robotics %XThis paper presents an analysis of planar bearing localization and mapping for visual servoing with known camera velocities. In particular, we investigate what is the subset of camera locations and environmental features that can be retrieved from dynamic observations obtained by a planar bearing sensor (nearly e.g., a pinhole camera). Results assume that the camera’s linear and angular velocities are available, which is equivalent to consider a unicycle vehicle carrying an onboard camera. Results hold if other system inputs are considered, e.g., an omnidirectional vehicle. The theoretical results may guide the design of nonlinear observers to estimate the variables of interest in real time to be applied to visual servoing schemes. An example of such an observer is discussed and simulated.

%B International Journal of Advanced Robotic Systems %V 10 %G eng %U http://www.intechopen.com/books/international_journal_of_advanced_robotic_systems/a-complete-observability-analysis-of-the-planar-bearing-localization-and-mapping-for-visual-servoing %N 197 %R 10.5772/54603 %0 Conference Paper %B IEEE Conference on Decision and Control %D 2013 %T Global Path Planning for Competitive Robotic Cars %A T. Rizano %A D. Fontanelli %A L. Palopoli %A L. Pallottino %A P Salaris %K Robotics %B IEEE Conference on Decision and Control %C Florence, Italy %P 4510 - 4516 %0 Conference Paper %B IEEE Conference on Decision and Control %D 2013 %T Shortest paths for wheeled robots with limited Field-Of-View: introducing the vertical constraint %A P Salaris %A A. Cristofaro %A L. Pallottino %A A. Bicchi %K Robotics %B IEEE Conference on Decision and Control %C Florence, Italy %P 5143 - 5149 %0 Conference Paper %B IEEE-RAS International Conference on Humanoid Robots %D 2013 %T Soft-Actuators in Cyclic Motion: Analytical Optimization of Stiffness and Pre-Load %A A. Velasco %A G M Gasparri %A M. Garabini %A L. Malagia %A P Salaris %A A. Bicchi %K Robotics %B IEEE-RAS International Conference on Humanoid Robots %C Atlanta, Georgia, USA %0 Journal Article %J International Journal of Robotics Research %D 2013 %T Synergy-Based Hand Pose Sensing: Optimal Glove Design %A M. Bianchi %A P Salaris %A A. Bicchi %K Robotics %XIn this paper we study the problem of improving human hand pose sensing device performance by exploiting the knowledge on how humans most frequently use their hands in grasping tasks. In a companion paper we studied the problem of maximizing the reconstruction accuracy of the hand pose from partial and noisy data provided by any given pose sensing device (a sensorized "glove") taking into account statistical a priori information. In this paper we consider the dual problem of how to design pose sensing devices, i.e. how and where to place sensors on a glove, to get maximum information about the actual hand posture. We study the continuous case, whereas individual sensing elements in the glove measure a linear combination of joint angles, the discrete case, whereas each measure corresponds to a single joint angle, and the most general hybrid case, whereas both continuous and discrete sensing elements are available. The objective is to provide, for given a priori information and fixed number of measurements, the optimal design minimizing in average the reconstruction error. Solutions relying on the geometrical synergy definition as well as gradient flow-based techniques are provided. Simulations of reconstruction performance show the effectiveness of the proposed optimal design.

%B International Journal of Robotics Research %V 32 %P 396-406 %G eng %N 4 %R 10.1177/0278364912474079 %0 Journal Article %J International Journal of Robotics Research %D 2013 %T Synergy-based Hand Pose Sensing: Reconstruction Enhancement %A M. Bianchi %A P Salaris %A A. Bicchi %K Robotics %XLow-cost sensing gloves for reconstruction posture provide measurements which are limited under several regards. They are generated through an imperfectly known model, are subject to noise, and may be less than the number of Degrees of Freedom (DoFs) of the hand. Under these conditions, direct reconstruction of the hand posture is an ill-posed problem, and performance can be very poor. This paper examines the problem of estimating the posture of a human hand using(low-cost) sensing gloves, and how to improve their performance by exploiting the knowledge on how humans most frequently use their hands. To increase the accuracy of pose reconstruction without modifying the glove hardware - hence basically at no extra cost - we propose to collect, organize, and exploit information on the probabilistic distribution of human hand poses in common tasks. We discuss how a database of such an a priori information can be built, represented in a hierarchy of correlation patterns or postural synergies, and fused with glove data in a consistent way, so as to provide a good hand pose reconstruction in spite of insufficient and inaccurate sensing data. Simulations and experiments on a low-cost glove are reported which demonstrate the effectiveness of the proposed techniques.

%B International Journal of Robotics Research %V 32 %P 407-424 %G eng %N 4 %R 10.1177/0278364912474078 %0 Conference Paper %B International Conference of Intelligent Robots and Systems - IROS 2012 %D 2012 %T Motion Planning for Two 3D-Dubins Vehicles with Distance Contraint %A H. Marino %A M. Bonizzato %A R. Bartalucci %A P Salaris %A L. Pallottino %K Robotics %B International Conference of Intelligent Robots and Systems - IROS 2012 %C Vilamoura, Algarve, Portugal %P 4702 - 4707 %8 October 7 - 12 %G eng %0 Conference Paper %B International Conference of Robotics and Automation - ICRA 2012 %D 2012 %T Optimality Principles in Stiffness Control: The VSA Kick %A M. Garabini %A A. Passaglia %A F. A. W. Belo %A P Salaris %A A. Bicchi %K Robotics %B International Conference of Robotics and Automation - ICRA 2012 %C Saint Paul, MN, USA %P 3341 - 3346 %8 May 14 - 18 %G eng %0 Journal Article %J International Journal of Robotics Research %D 2012 %T Shortest Paths for Finned, Winged, Legged and Wheeled Vehicles with Side-Looking Sensors %A P Salaris %A L. Pallottino %A A. Bicchi %K Robotics %B International Journal of Robotics Research %V 31 %P 997-1017 %G eng %N 8 %R 10.1177/0278364912446005 %0 Conference Paper %B International Conference of Intelligent Robots and Systems - IROS 2012- JTCF Award %D 2012 %T Synergy-based Optimal Desing of Hand Pose Sensing %A M. Bianchi %A P Salaris %A A. Bicchi %K Robotics %B International Conference of Intelligent Robots and Systems - IROS 2012- JTCF Award %C Vilamoura, Algarve, Portugal %P 3929 - 3935 %8 October 7 - 12 %G eng %0 Conference Paper %B Haptics Symposium %D 2012 %T On the Use of Postural Synergies to Improve Human Hand Pose Reconstruction %A M. Bianchi %A P Salaris %A A. Turco %A N. Carbonaro %A A. Bicchi %K Haptics %K Robotics %B Haptics Symposium %C Vancouver, Canada %P 91 - 98 %8 March 4 - 7 %G eng %0 Conference Paper %B Automatica.it 2011 %D 2011 %T On constrained optimal control problems in robotics %A L. Pallottino %A P Salaris %K Robotics %B Automatica.it 2011 %C Pisa, Italy %8 September 7 - 9 %G eng %0 Conference Paper %B 2011 IEEE/RSJ International Conference on Intelligent RObots and Systems %D 2011 %T From Optimal Planning to Visual Servoing with Limited FOV %A P Salaris %A L. Pallottino %A S. Hutchinson %A A. Bicchi %K Embedded Control %K Robotics %B 2011 IEEE/RSJ International Conference on Intelligent RObots and Systems %C S. Francisco, USA %P 2817-2824 %8 September 25 - 3 %G eng %0 Thesis %D 2011 %T From Optimal Synthesis to Optimal Visual Servoing for Autonomous Vehicles %A P Salaris %K Robotics %I University of Pisa %G eng %9 phd %0 Generic %D 2011 %T Optimal synthesis for nonholonomic vehicles with constrained side sensors %A P Salaris %A L. Pallottino %A A. Bicchi %K Embedded Control %K Robotics %G eng %0 Conference Paper %B 2011 IEEE/RSJ International Conference on Intelligent RObots and Systems %D 2011 %T Optimality Principles in Variable Stiffness Control: the VSA Hammer %A M. Garabini %A A. Passaglia %A F. A. W. Belo %A P Salaris %A A. Bicchi %K Robotics %B 2011 IEEE/RSJ International Conference on Intelligent RObots and Systems %C S. Francisco, USA %P 3770 - 3775 %8 September 25 - 3 %G eng %0 Conference Paper %B 2011 IEEE International Conference on Robotics and Automation %D 2011 %T Shortest Paths With Side Sensor %A P Salaris %A L. Pallottino %A A. Bicchi %K Embedded Control %K Robotics %B 2011 IEEE International Conference on Robotics and Automation %C Shangai, China %P 4875 - 4882 %8 May 9 - 13 %G eng %0 Conference Paper %B Automatica.it 2011 %D 2011 %T Variable stiffness actuators: muscles for the next generation of robots %A G. Grioli %A M. G. Catalano %A M. Garabini %A F. Bonomo %A A. Serio %A P Salaris %A F. A. W. Belo %A M. Mancini %A A. Bicchi %A A. Passaglia %K Robotics %B Automatica.it 2011 %C Pisa, Italy %8 September, 7 - 9 %G eng %0 Conference Paper %B Intelligent Robots and Systems (IROS), 2010 IEEE/RSJ International Conference on %D 2010 %T 3 known landmarks are enough for solving planar bearing SLAM and fully reconstruct unknown inputs %A F. A. W. Belo %A P Salaris %A A. Bicchi %K Embedded Control %K Robotics %B Intelligent Robots and Systems (IROS), 2010 IEEE/RSJ International Conference on %C St. Louis MO USA %P 2539 -2545 %8 October %G eng %R 10.1109/IROS.2010.5648896 %0 Journal Article %J IEEE Trans. on Robotics %D 2010 %T Shortest Paths for a Robot with Nonholonomic and Field-of-View Constraints %A P Salaris %A D. Fontanelli %A L. Pallottino %A A. Bicchi %K Embedded Control %K Robotics %B IEEE Trans. on Robotics %V 26 %P 269 - 281 %G eng %0 Book Section %D 2010 %T Visual Servoing via Advanced Numerical Methods %A D. Fontanelli %A P Salaris %A F. A. W. Belo %A A. Bicchi %E Graziano Chesi %E Koichi Hashimoto %K Robotics %I Springer %V 401 %P 335 - 360 %G eng %& Unicycle–like Robots with Eye-In-Hand Monocular Cameras: from PBVS Towards IBVS %0 Conference Paper %B Proc. IEEE International Conference on Decision and Control %D 2009 %T Shortest Paths for Non-holonomic Vehicles with Limited Field of View Camera %A L. Pallottino %A P Salaris %A D. Fontanelli %A A. Bicchi %K Embedded Control %K Robotics %XThis paper presents a complete characterization of shortest paths for unicycle-like nonholonomic mobile robots equipped with a pinhole camera rigidly fixed with limited Field-Of-View (FOV). We preliminarily provide an alphabet of optimal control words and then we demonstrate how to obtain the partition induced by shortest path in the vehicle plane. The word univocally associated to a region encodes the shortest path from any starting point in that region to the goal point of the mobile robot without violating the FOV constraints.

%B Proc. IEEE International Conference on Decision and Control %C Shangai, China %P 8434 - 8439 %8 December, 16 - 1 %G eng %0 Book Section %D 2009 %T Visual appearance mapping for optimal vision based servoing %A D. Fontanelli %A P Salaris %A F. A. W. Belo %A A. Bicchi %E B. Siciliano %E O. Khatib %E Groen, F. %K Robotics %S Springer Tracts in Advanced Robotics (STAR) %I Springer %V 54 - Experimental Robotics %P 353 - 362 %8 March 28 %G eng %0 Journal Article %J International Journal of Robotics Research %D 2009 %T Visual Servoing in the Large %A D. Fontanelli %A A. Danesi %A F. A. W. Belo %A P Salaris %A A. Bicchi %K Embedded Control %K Robotics %XIn this paper we consider the problem of maneuvering an autonomous robot in complex unknown environments using vision. The goal is to accurately servo a wheeled vehicle to a desired posture using only feedback from an on-board camera, taking into account the nonholonomic nature of the vehicle kinematics and the limited field-ofview of the camera. With respect to existing visual servoing schemes, which achieve similar goals locally (i.e. when the desired and actual camera views are sufficiently similar), we propose a method to visually navigate the robot through an extended visual map before eventually reaching the desired goal. The map comprises a set of images, previously stored in an exploratory phase, that convey both topological and metric information regarding the connectivity through feasible robot paths and the geometry of the environment, respectively. Experimental results on a laboratory setup are reported showing the practicality of the proposed approach.

%B International Journal of Robotics Research %V 28 %P 802 - 814 %8 June %G eng %0 Conference Paper %B IROS %D 2008 %T Optimal Paths in a Constrained Image Plane for Purely Image-Based Parking %A P Salaris %A F. A. W. Belo %A D. Fontanelli %A L. Greco %A A. Bicchi %K Robotics %XThis paper presents a correct solution to the optimal feedback control for a nonholonomic vehicle with limited field-of-view. Previous work on this subject has shown that the search for a shortest path can be limited to simple families of trajectories. We preliminarily provide an extension of the alphabet of optimal control words, to cover some regions of the vehicle plane where the synthesis of turns out to be suboptimal. The main contribution of this paper is an algorithm to translate the optimal synthesis to the image plane, thus enabling a purely image-based optimal control scheme. This allows better performance and increases the robustness of the overall process, avoiding the need of slowly-converging and error-prone parameter estimation algorithms. Simulations and experiments are reported which demonstrate the effectiveness of the proposed technique.

%B IROS %P 1673-1680 %8 22-26 Sept %G eng %0 Conference Paper %B Proc. Ints. Symp. Experimental Robotics %D 2008 %T Visual SLAM for Servoing for Appearance Based Topological Maps %A P Salaris %A F. A. W. Belo %A D. Fontanelli %A A. Bicchi %E Springer-Verlag %K Robotics %B Proc. Ints. Symp. Experimental Robotics %S Experimental Robotics %V 39/2008 %P 277-286 %G eng