[show abstract][hide abstract] ABSTRACT: This paper presents a switched homography-based visual control for differential drive vehicles. The goal is defined by an image taken at the desired position, which is the only previous information needed from the scene. The control takes into account the field-of-view constraints of the vision system through the specific design of the paths with optimality criteria. The optimal paths consist of straight lines and curves that saturate the sensor viewing angle. We present the controls that move the robot along these paths based on the convergence of the elements of the homography matrix. Our contribution is the design of the switched homography-based control, following optimal paths guaranteeing the visibility of the target.
Robotics and Automation, 2007 IEEE International Conference on; 05/2007
[show abstract][hide abstract] ABSTRACT: In this paper, we consider the problem of planning optimal paths for a differential-drive robot with limited sensing, that must maintain visibility of a fixed landmark as it navigates in its environment. In particular, we assume that the robot's vision sensor has a limited field of view (FOV), and that the fixed landmark must remain within the FOV throughout the robot's motion. We first investigate the nature of extremal paths that satisfy the FOV constraint. These extremal paths saturate the camera pan angle. We then show that optimal paths are composed of straight-line segments and sections of these these extremal paths. We provide the complete characterization of the shortest paths for the system by partitioning the plane into a set of disjoint regions, such that the structure of the optimal path is invariant over the individual regions
IEEE Transactions on Robotics 03/2007; · 2.57 Impact Factor
[show abstract][hide abstract] ABSTRACT: This work presents the minimal length paths, for a robot that maintains visibility of a landmark. The robot is a differential drive system and has limited sensing capabilities (range and angle of view). The optimal paths are composed of straight lines and curves that saturate the camera pan angle.
Intelligent Robots and Systems, 2004. (IROS 2004). Proceedings. 2004 IEEE/RSJ International Conference on; 01/2004
[show abstract][hide abstract] ABSTRACT: In this paper we describe a new representation for a configuration space for formations of robots that translate in the plane. What makes this representation unique is that it is permutation-invariant, so the relabeling of robots does not affect the configuration. Earlier methods generally either pre-assign roles for each individual robot, or rely on local planning and behaviors to build emergent behaviors. Our method first plans the formation as a set, and only afterwards determines which robot takes which role. To build our representation of this formation space, we make use of a property of complex polynomials: they are unchanged by permutations of their roots. Thus we build a characteristic polynomial whose roots are the robot locations, and use its coefficients as a representation. Mappings between work spaces and formation spaces amount to building and solving polynomials. In this paper we also perform basic path planning on this new representation, and show some practical and theoretical properties. We show that the paths generated are invariant-relative to their endpoints - with respect to linear coordinate transforms, and in most cases produce reasonable, if not linear, paths from start to finish.
Robotics and Automation, 2004. Proceedings. ICRA '04. 2004 IEEE International Conference on; 01/2004
[show abstract][hide abstract] ABSTRACT: This work addresses the problem of computing the motions of a robot observer in order to maintain visibility of a moving target at a fixed surveillance distance. In this paper, we deal specifically with the situation in which the observer has bounded velocity. We give necessary conditions for the existence of a surveillance strategy and give an algorithm that generates surveillance strategies.
Robotics and Automation, 2004. Proceedings. ICRA '04. 2004 IEEE International Conference on;