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The covariance of every unbiased estimator is bounded by the Cramer-Rao lower bound, which is the inverse of Fisher's information matrix. This paper shows that, for the case of localization with range-finders, Fisher's matrix is a function of the expected readings and of the orientation of the environment's surfaces at the sensed points. The matrix also offers a mathematically sound way to characterize...
This paper presents an approach for sonar feature map building. The approach is composed of extracting features at the data-level fusion stage and fusing the extracted features with the registered features in the map at the feature-level fusion stage. A data-level fusion model, termed three measurements association model (TMAM), has been developed for associating three measurements with a line or...
Traditionally in monocular SLAM, interest features are extracted and matched in successive images. Outliers are rejected a posteriori during a pose estimation process, and then the structure of the scene is reconstructed. In this paper, we propose a new approach for computing robustly and simultaneously the 3D camera displacement, the scene structure and the illumination changes directly from image...
This paper describes a truss climbing robot we designed and prototyped. The robot has a minimalist design with three motive degrees of freedom that enable movement along three-dimensional truss structures. This robot can form a six-degree-of-freedom structure by connecting to another identical module using a passive bar as a medium. We present the design and implementation of this robot, control algorithms...
When using an extended Kalman filter (EKF) in simultaneous localization and mapping (SLAM) for a mobile robot with bearing-only measurements, it is crucial to correctly assign correspondences between measurements and registered features in the map, otherwise the filter diverges or becomes inconsistent. Conventional methods based on the Mahalanobis distance metric may produce data association ambiguities...
A novel adaptive unscented Kalman filter (UKF) based on dual estimation structure is proposed. The filter is composed of two parallel master-slave UKFs, while the master one estimates the states and the slave one estimates the diagonal elements of the noise covariance matrix for the master UKF. By estimating the noise covariance online, the proposed method is able to compensate the errors resulting...
The authors proposed a methodology of assisting the patients who were suffering from mobility impairment of finger and thumb joints, with exoskeletal devices. The types of exoskeletal assistive devices for such patients were categorized into several groups based on required functions which are derived from the patients' condition. One of the categories, "joint motion compensator" is a novel...
Localization for low cost humanoid or animal-like personal robots has to rely on cheap sensors and has to be robust to user manipulations of the robot. We present a visual localization and map-learning system that relies on vision only and that is able to incrementally learn to recognize the different rooms of an apartment from any robot position. This system is inspired by visual categorization algorithms...
This paper considers two approaches to the problem of vision and self-localization on a mobile robot. In the first approach, the perceptual processing is primarily bottom-up, with visual object recognition entirely preceding localization. In the second, significant top-down information is incorporated, with vision and localization being intertwined. That is, the processing of vision is highly dependent...
This paper presents an integrated framework for recognizing 3D human posture from 2D images. A flexible combinational algorithm motivated by the novel view expressed by Cyr and Kimia (2004) is proposed to generate the aspects of 3D human postures as the posture prototype using features extracted from the collected 2D images sampled at random intervals from the viewing sphere. Frequency and phase information...
Our research perspective is to develop mechanisms for gathering information efficiently in disaster sites. Ideally this requires mechanisms with capabilities of flexible, on-site, adaptation of the overall shape and of the locomotion strategy to unknown and unstable environments. We have been developing three-legged modular robots which can be interconnected to cooperatively achieve multiple locomotion...
A new efficient method of calibration for catadioptric sensors is presented in this paper. It is based on an accurate reconstruction of the mirror by means of polarization imaging and it permits to relax most of the constraints related to the calibration of the catadioptric systems. No image processing and no calibration pattern are required so that the calibration can be performed in "one click"...
In this paper, we develop a prototype of a new snake-like robot using the screw drive mechanism, and design a control system design for trajectory tracking. First, we explain the outline of the snake-like robot using the screw drive units and joint units, as well as the principle of the screw drive mechanism. Next, in order to achieve the trajectory tracking of the robot, we derive a kinematic model...
In this paper the first application of utilizing a unique 3D real-time mapping sensor for sequential 3D map building within a visual simultaneous localization and mapping (SLAM) framework in unknown cluttered urban search and rescue (USAR) environments is proposed. The sensor utilizes a digital fringe projection and phase shifting technique to provide real-time 2D and 3D sensory information of the...
We improve and adjust usual weak calibration techniques to the case of stereo video microscopes: Harris detector using a simplex optimization method for feature points detection, a "cha" window based ZNSSD correlation for points matching. Images of a pattern made with a water drop covered with nickel fillings are used. The result is validated by constructing 3D view of a micromanipulation...
A human can control dynamic properties of his/her own body naturally and effectively according to tasks by utilizing the perceived information of environmental characteristics. If dynamic properties of human movements depending on environmental characteristics can be described quantitatively, there would be expected to design and develop a novel human-machine system in which an operator can manipulate...
This paper is about the autonomous control of an autonomous underwater vehicle (AUV), and the particular considerations required to allow proper control while towing a 100-meter vector sensor array. Mission related objectives are tempered by the need to consider the effect of a sequence of maneuvers on the motion of the towed array which is thought not to tolerate sharp bends or twists in sensitive...
In this article, we propose a fast on-line closed loop identification method of continuous-time combined with an output feedback controller of the generalized proportional integral type (GPI), for the control of an uncertain flexible robotic arm with unknown mass at the tip, including a Coulomb friction term in the motor dynamics. A fast, non-asymptotic, algebraic identification method is used to...
We develop a switched cooperative control scheme, to coordinate groups of ground and aerial vehicles for the purpose of locating a moving target in a given area. We do so by stabilizing the ground group into a guarding formation using a navigation function, and then steering the aerial group along a trajectory that uniformly scans the enclosed regions. The novelty of the approach lays in combining...
The task of visual surveillance involves pervasively observing multiple targets as they move through a field of sensor nodes. Mutational analysis and shape based control have been proposed to overcome the limitations of current feature (point) based visual servoing and tracking techniques generally employed to provide an optimal solution for the surveillance task. Hausdorff tracking paradigm for visual...
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