Hierarchical Control of a Team of Quadrotors for Cooperative Active Target Tracking

International audienceThis paper proposes a novel active target tracking strategy for a team of cooperating quadrotors equipped with 3-D range-finding sensors. The work builds upon previous research of the authors, and adopts a realistic nonlinear dynamic model for the quadrotors. A hierarchical controller is designed for the generation and tracking of the desired optimal trajectories of the aerial vehicles, and a discrete-time Kalman filter is used for fusing their local estimates of the target position. Under suitable conditions, it is shown that the cost function for the D-optimality criterion that the quadrotors aim at collaboratively reduce, possesses a single global minimum and no local minima. Numerical simulations and real-world experiments show the effectiveness of the proposed control strategy

SegICP: Integrated Deep Semantic Segmentation and Pose Estimation

Recent robotic manipulation competitions have highlighted that sophisticated robots still struggle to achieve fast and reliable perception of task-relevant objects in complex, realistic scenarios. To improve these systems' perceptive speed and robustness, we present SegICP, a novel integrated solution to object recognition and pose estimation. SegICP couples convolutional neural networks and multi-hypothesis point cloud registration to achieve both robust pixel-wise semantic segmentation as well as accurate and real-time 6-DOF pose estimation for relevant objects. Our architecture achieves 1cm position error and <5^\circ$ angle error in real time without an initial seed. We evaluate and benchmark SegICP against an annotated dataset generated by motion capture.Comment: IROS camera-read

Uncalibrated video compass for mobile robots from paracatadioptric line images

Abstract — Due to their panoramic field of view, catadioptric cameras are becoming ubiquitous in many robotics and computer vision applications. Catadioptric cameras with a unique viewpoint are of primary interest, among these is the case where the reflective surface is a parabolic mirror and the camera satisfies the orthographic projection model and which we call paracatadioptric. We here present a new geometrical property (called disparity-circles property) for paracatadioptric cameras and use it to design a video compass algorithm that can compute the 1-axis rotation angle between two views of at least two parallel lines, without any need of internal camera calibration parameters. We present a linear closed form solution suitable for real-time implementation. We then study the performances of our algorithm, its sensitivity to image noise and propose also experimental results with a paracatadioptric camera mounted on a mobile robotic platform. (a) (b

The Epipolar Geometry Toolbox: multiple view geometry and visual servoing for MATLAB

Abstract — The Epipolar Geometry Toolbox (EGT) was realized to provide a MATLAB user with an extensible framework for the creation and visualization of multi-camera scenarios and the manipulation of the visual information and the geometry between them. Functions provided, for both pin-hole and panoramic vision sensors, include camera placement and visualization, computation and estimation of epipolar geometry entities and many others. The compatibility of EGT with the Robotics Toolbox [7] allows to address general vision-based control issues. Two applications of EGT to visual servoing tasks are here provided. This article introduces the Toolbox in tutorial form. Examples are provided to show its capabilities. The complete toolbox, the detailed manual and demo examples are freely available on the EGT web site [21]. I