Showing papers on "Mobile robot navigation published in 2002"

Vision for mobile robot navigation: a survey

Abstract: Surveys the developments of the last 20 years in the area of vision for mobile robot navigation. Two major components of the paper deal with indoor navigation and outdoor navigation. For each component, we have further subdivided our treatment of the subject on the basis of structured and unstructured environments. For indoor robots in structured environments, we have dealt separately with the cases of geometrical and topological models of space. For unstructured environments, we have discussed the cases of navigation using optical flows, using methods from the appearance-based paradigm, and by recognition of specific objects in the environment.

Mobile Robot Localization and Mapping with Uncertainty using Scale-Invariant Visual Landmarks

Abstract: A key component of a mobile robot system is the ability to localize itself accurately and, simultaneously, to build a map of the environment. Most of the existing algorithms are based on laser rang...

Simultaneous localization and map-building using active vision

Abstract: An active approach to sensing can provide the focused measurement capability over a wide field of view which allows correctly formulated simultaneous localization and map-building (SLAM) to be implemented with vision, permitting repeatable longterm localization using only naturally occurring, automatically-detected features. In this paper, we present the first example of a general system for autonomous localization using active vision, enabled here by a high-performance stereo head, addressing such issues as uncertainty-based measurement selection, automatic map-maintenance, and goal-directed steering. We present varied real-time experiments in a complex environment.

Navigation Strategies for Exploring Indoor Environments

Abstract: In this paper, we investigate safe and efficient map-building strategies for a mobile robot with imperfect control and sensing. In the implementation, a robot equipped with a range sensor builds apolygonal map layout of a previously unknown indoor environment. The robot explores the environment and builds the map concurrently by patching together the local models acquired by the sensor into a global map. A well-studied and related problem is the simultaneous localization and mapping SLAM problem, where the goal is to integrate the information collected during navigation into the most accurate map possible. However, SLAM does not address the sensor-placement portion of the map-building task. That is, given the map built so far, where should the robot go next? This is the main question addressed in this paper. Concretely, an algorithm is proposed to guide the robot through a series of ?good? positions, where ?good? refers to the expected amount and quality of the information that will be revealed at each new location. This is similar to the next-best-view NBV problem studied in computer vision and graphics. However, in mobile robotics the problem is complicated by several issues, two of which are particularly crucial. One is to achieve safe navigation despite an incomplete knowledge of the environment and sensor limitations e.g., in range and incidence. The other issue is the need to ensure sufficient overlap between each new local model and the current map, in order to allow registration of successive views under positioning uncertainties inherent to mobile robots. To address both issues in a coherent framework, in this paper we introduce the concept of a safe region, defined as the largest region that is guaranteed to be free of obstacles given the sensor readings made so far. The construction of a safe region takes sensor limitations into account. In this paper we also describe an NBV algorithm that uses the safe-region concept to select the next robot position at each step. The new position is chosen within the safe region in order to maximize the expected gain of information under the constraint that the local model at this new position must have a minimal overlap with the current global map. In the future, NBV and SLAM algorithms should reinforce each other. While a SLAM algorithm builds a map by making the best use of the available sensory data, an NBV algorithm, such as that proposed here, guides the navigation of the robot through positions selected to provide the best sensory inputs.

Effective reinforcement learning for mobile robots

Abstract: Programming mobile robots can be a long, time-consuming process. Specifying the low-level mapping from sensors to actuators is prone to programmer misconceptions, and debugging such a mapping can be tedious. The idea of having a robot learn how to accomplish a task, rather than being told explicitly, is an appealing one. It seems easier and much more intuitive for the programmer to specify what the robot should be doing, and to let it learn the fine details of how to do it. In this paper, we introduce a framework for reinforcement learning on mobile robots and describe our experiments using it to learn simple tasks.

An experiment in integrated exploration

Abstract: Integrated exploration strategy advocated in this paper refers to a tight coupling between the tasks of localization, mapping, and motion control and the effect of this. coupling on the overall effectiveness of an exploration strategy. Our approach to exploration calls for a balanced evaluation of alternative motion actions from the point of view of information gain, localization quality, and navigation cost. To provide a uniform basis of comparison of localization quality between different locations, a "localizability" metric is introduced. It is based on the estimate of the lowest vehicle pose covariance attainable from a given location.

Improved fast replanning for robot navigation in unknown terrain

Abstract: Mobile robots often operate in domains that are only incompletely known, for example, when they have to move from given start coordinates to given goal coordinates in unknown terrain. In this case, they need to be able to replan quickly as their knowledge of the terrain changes. Stentz' Focussed Dynamic A* is a heuristic search method that repeatedly determines a shortest path from the current robot coordinates to the goal coordinates while the robot moves along the path. It is able to replan one to two orders of magnitudes faster than planning from scratch since it modifies previous search results locally. Consequently, it has been extensively used in mobile robotics. In this paper, we introduce an alternative to Focussed Dynamic A* that implements the same navigation strategy but is algorithmically different. Focussed Dynamic A* Lite is simpler, easier to understand, easier to analyze and easier to extend than Focussed Dynamic A*, yet is more efficient. We believe that our results will make D*-like replanning algorithms even more popular and enable robotics researchers to adapt them to additional applications.

Experiences with a mobile robotic guide for the elderly

Abstract: This paper describes an implemented robot system, which relies heavily on probabilistic AI techniques for acting under uncertainty. The robot Pearl and its predecessor Flo have been developed by a multi-disciplinary team of researchers over the past three years. The goal of this research is to investigate the feasibility of assisting elderly people with cognitive and physical activity limitations through interactive robotic devices, thereby improving their quality of life. The robot's task involves escorting people in an assisted living facility-a time-consuming task currently carried out by nurses. Its software architecture employs probabilistic techniques at virtually all levels of perception and decision making. During the course of experiments conducted in an assisted living facility, the robot successfully demonstrated that it could autonomously provide guidance for elderly residents. While previous experiments with fielded robot systems have provided evidence that probabilistic techniques work well in the context of navigation, we found the same to be true of human robot interaction with elderly people.

A resource-adaptive mobile navigation system

Abstract: The design of mobile navigation systems adapting to limited resources will be an important future challenge. Since typically several different means of transportation have to be combined in order to reach a destination, the user interface of such a system has to adapt to the user's changing situation. This applies especially to the alternating use of different technologies to detect the user's position, which should be as seamless as possible. This article presents a hybrid navigation system that relies on different technologies to determine the user's location and that adapts the presentation of route directions to the limited technical resources of the output device and the limited cognitive resources of the user.

Behavior-based robot navigation on challenging terrain: A fuzzy logic approach

Abstract: This paper presents a new strategy for behavior-based navigation of field mobile robots on challenging terrain, using a fuzzy logic approach and a novel measure of terrain traversability. A key feature of the proposed approach is real-time assessment of terrain characteristics and incorporation of this information in the robot navigation strategy. Three terrain characteristics that strongly affect its traversability, namely, roughness, slope, and discontinuity, are extracted from video images obtained by on-board cameras. This traversability data is used to infer, in real time, the terrain Fuzzy Rule-Based Traversability Index, which succinctly quantifies the ease of traversal of the regional terrain by the mobile robot. A new traverse-terrain behavior is introduced that uses the regional traversability index to guide the robot to the safest and the most traversable terrain region. The regional traverse-terrain behavior is complemented by two other behaviors, local avoid-obstacle and global seek-goal. The recommendations of these three behaviors are integrated through adjustable weighting factors to generate the final motion command for the robot. The weighting factors are adjusted automatically, based on the situational context of the robot. The terrain assessment and robot navigation algorithms Are implemented on a Pioneer commercial robot and field-test studies are conducted. These studies demonstrate that the robot possesses intelligent decision-making capabilities that are brought to bear in negotiating hazardous terrain conditions during the robot motion.

Development and evaluation of an interactive humanoid robot "Robovie"

Abstract: In this paper, we report about a new interaction-oriented robot, which communicates with humans and will participate in human society as our partner. For realizing such a robot, we have started a new collaborative work between cognitive science and robotics. In the way of robotics, we have developed a humanoid robot named "Robovie" that has enough physical expression ability. On the other hand, through cognitive experiments, we obtained important ideas about the robot's body property. To incorporate these ideas, we have developed software architecture and implemented autonomous interactive behaviors to the robot. Further, we have evaluated the robot's performance of the interactive behaviors through psychological experiments. The experiments reveal how humans recognize the robot.

Localization for mobile robot teams using maximum likelihood estimation

Abstract: This paper describes a method for localizing the members of a mobile robot team, using only the robots themselves as landmarks, that is, we describe a method whereby each robot can determine the relative range, bearing and orientation of every other robot in the team, without the use of GPS, external landmarks, or instrumentation of the environment. Our method assumes that each robot is able to measure the relative pose of nearby robots, together with changes in its own pose. Using a combination of maximum likelihood estimation and numerical optimization, we can subsequently infer the relative pose of every robot in the team. This paper describes the basic formalism, its practical implementation, and presents experimental results obtained using a team of four mobile robots.

An experimental comparison of localization methods continued

Abstract: Localization is one of the fundamental problems in mobile robot navigation. Past experiments have shown that, in general, grid-based Markov localization is more robust than Kalman filtering while the latter can be more accurate than the former Recently new methods for localization employing particle filters have become popular. In this paper, we compare different localization methods using Kalman filtering, grid-based Markov localization, Monte Carlo Localization (MCL), and combinations thereof. We give experimental evidence that a combination of Markov localization and Kalman filtering as well as a variant of MCL outperform the other methods in terms of accuracy, robustness, and time needed for recovering from manual robot displacement, while requiring only few computational resources.

Position based visual servoing: keeping the object in the field of vision

Abstract: Visual servoing requires an object in the field of view of the camera, in order to control the robot evolution. Otherwise, the virtual link is broken and the control loop cannot continue to be closed. In this paper, a novel approach is presented in order to guarantee that the object remains in the field of view of the camera during the whole robot motion. It consists in tracking an iteratively computed trajectory. A position based modeling adapted to a moving target object is established, and is used to control the trajectory. A nonlinear decoupling approach is then used to control the robot. Experiments, demonstrating the capabilities of this approach, have been conducted on a Cartesian robot connected to a real time vision system, with a CCD camera mounted on the end effector of the robot.

A Social Robot that Stands in Line

Abstract: Recent research in mobile robot navigation make it feasible to utilize autonomous robots in service fields. But, such applications require more than just navigation. To operate in a peopled environment, robots should recognize and act according to human social behavior. In this paper, we present the design and implementation of one such social behavior: a robot that stands in line much as people do. The system employs stereo vision to recognize lines of people, and uses the concept of personal space for modeling the social behavior. Personal space is used both to detect the end of a line and to determine how much space to leave between the robot and the person in front of it. Our model of personal space is based on measurements from people forming lines. We demonstrate our ideas with a mobile robot navigation system that can purchase a cup of coffee, even if people are waiting in line for service.

Roball, the Rolling Robot

Abstract: Designing a mobile robotic toy is challenging work The robot must be appealing to children and create interesting interactions while facing the wide variety of situations that can be experienced while playing with a child, and all at a reasonable cost In this paper we present Roball, a ball-shaped robot that moves by making its external spherical shell rotate Such design for a mobile robotic toy shows robustness in handling unstructured environments and unconstrained interactions with children Results show that purposeful movements of the robot, its physical structure and locomotion dynamics generate interesting new games influenced by the environment and the child

Systems and methods with integrated GPS and dead reckoning capabilities

Abstract: Systems and methods are provided for complementary navigation devices with various integrated positioning functionality. The navigation method includes providing a first navigation device. The first navigation device includes a triangulation positioning functionality. The method includes providing a second navigation device adapted to communicate with the first navigation device. The second navigation device includes one or more dead reckoning positioning components. The method further includes resolving a position of the first and the second navigation devices. Resolving the position includes using the one or more dead reckoning positioning components in complement to the triangulation positioning functionality to determine the position when the triangulation positioning functionality is degraded.

The odometry error of a mobile robot with a synchronous drive system

Abstract: This paper presents an error modeling of an odometry system for a synchronous-drive system and a possible strategy for evaluating this error. The odometry error is modeled by introducing four parameters characterizing its systematic and nonsystematic components (translational and rotational). The nonsystematic errors are expressed in terms of a covariance matrix, which depends on both the previous four parameters and the path followed by the mobile robot. In contrast to previous approaches which require assuming a particular path (straight or circular) in order to compute this covariance matrix, the general formulas are derived. We suggest a possible strategy for simultaneously estimating the four model parameters. It is shown that our strategy only requires measuring the change in the orientation and position between the initial and final configurations of the robot, related to suitable robot motions. In other words, it is unnecessary to know the actual path followed by the robot. We illustrate the proposed strategy by discussing the accuracy of the parameters estimation, and present some of the experimental results obtained with the mobile robot Nomad 150.

Pseudolite Applications in Positioning and Navigation: Progress and Problems

Abstract: Global navigation satellite systems have been revolutionising surveying, geodesy, navigation and other position/location sensitive disciplines. However, there are two intrinsic shortcomings in such satellite-based positioning systems: signal attenuation and dependence on the geometric distribution of the satellites. Consequently, the system performance can decrease significantly under some harsh observing conditions. To tackle this problem, some new concepts of positioning with the use of pseudo-satellites have been developed and tested. Pseudo-satellites, also called pseudolites, are ground-based transmitters that can be easily installed wherever they are needed. They therefore offer great flexibility in positioning and navigation applications. Although some initial experimental results are encouraging, there are still some challenging issues that need to be addressed. This paper reviews the historical pseudolite hardware developments and recent progress in pseudolite-based positioning, and discusses the current technical issues.

Using gesture and speech control for commanding a robot assistant

Abstract: Giving advice to a mobile robot assistant still requires classical user interfaces. A more intuitive way of commanding is achieved by verbal or gesture commands. In this article, we present new approaches and enhancements for established methods that are in use in our laboratory. Our aim is to interact with a robot using natural and direct communication techniques to facilitate robust performance of simple tasks. Within this paper, we describe the robot's vision and speech recognition system. Then, we display robot control for selecting the appropriate robot reaction for solving basic manipulation tasks.

A real-time limit-cycle navigation method for fast mobile

Abstract: A mobile robot should be designed to navigate with collision avoidance capability in the real world, flexibly coping with the changing environment. In this paper, a novel limit-cycle navigation method is proposed for a fast mobile robot using the limit-cycle characteristics of a 2nd-order nonlinear function. It can be applied to the robot operating in a dynamically changing environment, such as in a robot soccer system. By adjusting the radius of the motion circle and the direction of obstacle avoidance, the navigation method proposed enables a robot to maneuver smoothly towards any desired destination. Simulations and real experiments using a robot soccer system demonstrate the merits and practical applicability of the proposed method. 11 12 13 14 15 16 17 © 2002 Published by Elsevier Science B.V. 18

Robot system and robot apparatus control method

Abstract: The present invention aims to provide an improved entertainment property. In a robot system where a plurality of robot apparatus act autonomously, each robot apparatus has wireless communication means, and when the robot apparatus make conversation between themselves, the contents of the conversation are transmitted to and received by the robot apparatus as a command and/or a semantics through the wireless communication means of both.

A Genetic Algorithm for Mobile Robot Localization Using Ultrasonic Sensors

Abstract: A mobile robot requires the perception of its local environment for position estimation. Ultrasonic range data provide a robust description of the local environment for navigation. This article presents an ultrasonic sensor localization system for autonomous mobile robot navigation in an indoor semi-structured environment. The proposed algorithm is based upon an iterative non-linear filter, which utilizes matches between observed geometric beacons and an a-priori map of beacon locations, to correct the position and orientation of the vehicle. A non-linear filter based on a genetic algorithm as an emerging optimization method to search for optimal positions is described. The resulting self-localization module has been integrated successfully in a more complex navigation system. Experiments demonstrate the effectiveness of the proposed method in real world applications.

Collective construction with multiple robots

Abstract: We study the problem of construction by autonomous mobile robots focusing on the coordination strategy employed by the robots to solve a simple construction problem efficiently. In particular we address the problem of constructing a linear 2D structure in a planar bounded environment. A "minimalist" single-robot solution to the problem is given, as well as two multi-robot solutions, which are natural extensions to the single-robot approach, with varying degrees of inter-robot communication. Results show that with minimal inter-robot communication (1 bit of state), there is a significant improvement in the system performance. This improvement is invariant with respect to the size of the environment.

Predictive autonomous robot navigation

Abstract: This paper considers the problem of a robot navigating in a crowded or congested environment. A robot operating in such an environment can get easily blocked by moving humans and other objects. To deal with this problem it is proposed to attempt to predict the motion trajectory of humans and obstacles. Two kinds of prediction are considered: short-term and long-term. The short-term prediction refers to the one-step ahead prediction and the long-term to the prediction of the final destination point of the obstacle's movement. The robot movement is controlled by a partially observable Markov decision process (POMDP). POMDPs are utilized because of their ability to model information about the robot's location and sensory information in a probabilistic manner. The solution of a POMDP is computationally expensive and thus a hierarchical representation of POMDPs is used.