Organizational Unit:

Institute for Robotics and Intelligent Machines (IRIM)

Permanent Link

https://hdl.handle.net/1853/70657

Includes Organization(s)

Organizational Unit

Biorobotics and Human Modeling Lab

Organizational Unit

Humanoid Robotics Laboratory

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Publication Search Results

Now showing 1 - 10 of 10

A novel tiered sensor fusion approach for terrain characterization and safe landing assessment

(Georgia Institute of Technology, 2006-03) Serrano, Navid ; Bajracharya, Max ; Howard, Ayanna M. ; Seraji, Homayoun

This paper presents a novel, tiered sensor fusion methodology for real-time terrain safety assessment. A combination of active and passive sensors, specifically, radar, lidar, and camera, operate in three tiers according to their inherent ranges of operation. Low-level terrain features (e.g. slope, roughness) and high-level terrain features (e.g. hills, craters) are integrated using principles of reasoning under uncertainty. Three methodologies are used to infer landing safety: fuzzy reasoning, probabilistic reasoning, and evidential reasoning. The safe landing predictions from the three fusion engines are consolidated in a subsequent decision fusion stage aimed at combining the strengths of each fusion methodology. Results from simulated spacecraft descents are presented and discussed.
A Human-Robot Mentor-Protégé Relationship to Learn Off-Road Navigation Behavior

(Georgia Institute of Technology, 2005-10) Howard, Ayanna M. ; Werger, Barry ; Seraji, Homayoun

In this paper, we present an approach to transfer human expertise for learning off-road navigation behavior to an autonomous mobile robot. The methodology uses the concept of humanized intelligence to combine principal component analysis and neural network learning to embed human driving expertise onto mobile robots. The algorithms are tested in the field using a commercial Pioneer 2AT robot to demonstrate autonomous traversal over rough natural terrain.
Integrating Terrain Maps into a Reactive Navigation Strategy

(Georgia Institute of Technology, 2003-09) Howard, Ayanna M. ; Werger, Barry ; Seraji, Homayoun

This paper presents a new method for integrating terrain maps into a reactive navigation strategy of field mobile robots operating on rough terrain. The method incorporates the Regional Traversability Map, a fuzzy map representation of traversal difficulty of the regional terrain, into the navigation logic. A map-based regional navigation behavior provides speed and direction recommendations based on the current status of the robot. In addition, recommendations from two sensor-based reactive behaviors, local avoid-obstacle and regional traverse-terrain, are fused with the map-based regional behavior to construct a comprehensive navigation system. The algorithms are tested both in graphical simulations and in the field using a commercial Pioneer 2AT robot to demonstrate traversal over rough natural terrain.
A Rule-Based Fuzzy Safety Index for Landing Site Risk Assessmen

(Georgia Institute of Technology, 2002-06) Howard, Ayanna M. ; Seraji, Homayoun

This paper presents a fuzzy rule-based safety index that quantifies the ease-of-landing a spacecraft on a planetary surface based on sensor-derived measurements of terrain characteristics. These characteristics include, but are not limited to, slope and roughness. The proposed representation of terrain safety incorporates an intuitive, linguistic approach for expressing terrain characteristics that is robust with respect to imprecision and uncertainty in the sensor measurements. The risk assessment methodology is tested and validated with a set of simulated data. These tests demonstrate the capability of the algorithm for perceiving hazards associated with landing on a planetary surface.
Terrain-Based Navigation of Planetary Rovers: A Fuzzy Logic Approach

(Georgia Institute of Technology, 2001-06) Seraji, Homayoun ; Howard, Ayanna M. ; Tunstel, Edward

This paper presents a new strategy for autonomous navigation of eld mobile robots on hazardous natural terrain using a fuzzy logic approach and a novel mea- sure of terrain traversability. The navigation strategy is comprised of three simple, independent behaviors: seek-goal, traverse-terrain, and avoid-obstacle. The recommendations from these three behaviors are com- bined through appropriate weighting factors to gen- erate the nal steering and speed commands that are executed by the robot. The weighting factors are pro- duced by fuzzy logic rules that take into account the current status of the robot. This navigation strategy requires no a priori information about the environ- ment, and uses the on-board traversability analysis to enable the robot to select relatively easy-to-traverse paths autonomously. Field test results obtained from implementation of the proposed algorithms on the commercial Pioneer AT rover are presented. These results demonstrate the real-time capabilities of the terrain assessment and fuzzy logic navigation algorithms.
Safe Navigation on Hazardous Terrain

(Georgia Institute of Technology, 2001-05) Seraji, Homayoun ; Howard, Ayanna M. ; Tunstel, Edward

This paper presents a new strategy for autonomous navigation of field mobile robots on hazardous natural terrain using a fuzzy logic approach and a measure of terrain traversability. The navigation strategy comprises three simple, independent behaviors: seek-goal, traverse-terrain, and avoid-obstacle. The recommendations from these three behaviors are combined through appropriate weighting factors to generate the final steering and speed commands that are executed by the robot. The weighting factors are produced by fuzzy logic rules that take into account the current status of the robot. This navigation strategy requires no a priori information about the environment, and uses the on-board traversability analysis to enable the robot to select relatively easy-to-traverse paths autonomously. Field test results obtained from implementation of the proposed algorithms on the commercial Pioneer All Terrain rover are presented. These results demonstrate the real-time capabilities of the terrain assessment and fuzzy logic navigation algorithms.
Fuzzy Rule-Based Reasoning for Rover Safety and Survivability

(Georgia Institute of Technology, 2001-05) Tunstel, Edward ; Howard, Ayanna M. ; Seraji, Homayoun

Operational safety and health monitoring are critical matters for autonomous field mobile robots such as planetary rovers operating on challenging terrain. The paper describes relevant rover safety and health issues and presents an approach to maintaining vehicle safety in a navigational context. The proposed rover safety module is composed of two distinct components: safe attitude (pitch and roll) management and safe traction management. Fuzzy logic approaches to reasoning about safe attitude and traction management are presented, wherein sensing of safety status and perception of terrain quality are used to infer safe speeds of traversal. Results of field tests and laboratory experiments are also described. The approach provides an intrinsic safety cognizance and a capacity for reactive mitigation of navigation risks.
A Rule-Based Fuzzy Traversability Index for Mobile Robot Navigation

(Georgia Institute of Technology, 2001-05) Howard, Ayanna M. ; Seraji, Homayoun ; Tunstel, Edward

This paper presents a rule-based fuzzy traversability index that quantifies the ease-of-traversal of a terrain by a mobile robot based on real-time measurements of terrain characteristics retrieved from imagery data. These characteristics include, but are not limited to slope, roughness, hardness, and discontinuity. The proposed representation of terrain traversability incorporates an intuitive, linguistic approach for expressing terrain characteristics that is robust with respect to imprecision and uncertainty in the terrain measurements. The terrain assessment method is tested and validated with a set of real-world imagery data. These tests demonstrate the capability of the terrain classification algorithm for perceiving hazards associated with terrain traversal.
Real-Time Assessment of Terrain Traversability for Autonomous Rover Navigation

(Georgia Institute of Technology, 2000-11) Howard, Ayanna M. ; Seraji, Homayoun

This paper presents a novel technique for real-time measurement of terrain characteristics and incorporation of this information into the navigation strategy of an autonomous mobile robot. The proposed methodology utilizes a fuzzy logic framework for on-board analysis of terrain traversability, and develops a set of fuzzy navigation rules that guide the rover toward the safest and the most traversable terrain. In addition, a simple goal-seeking behavior is used to drive the rover from its initial position to a user-specified goal position. The overall navigation strategy, consisting of terrain-traverse and goal-seeking behaviors, requires no a priori information about the environment, and uses the on-board traversability analysis to enable the rover to select easy-to-traverse paths to the goal autonomously. The terrain traversability navigation rules are tested and validated with a set of physical rover experiments. These experiments demonstrate the real-time capability of the terrain assessment and fuzzy navigation algorithms.
A Real-Time Autonomous Rover Navigation System

(Georgia Institute of Technology, 2000-06) Howard, Ayanna M. ; Seraji, Homayoun

To enable real-time autonomous navigation, a mobile robot is equipped with on-board processing power, image-processing algorithms, and a fuzzy computation engine that allow the rover to safely navigate to a designated goal while avoiding obstacles and impassible terrains. The underlying architecture discussed in this paper utilizes real-time measurement of terrain characteristics and a fuzzy logic framework for onboard analysis of terrain traversability. The overall navigation strategy, consisting of terrain-traverse and goal-seeking behaviors, requires no a priori information about the environment, and uses the on-board traversability analysis to enable the rover to select easy-to-traverse paths to the goal autonomously. The rover navigation system is tested and validated with a set of physical rover experiments. These experiments demonstrate the real-time capability of the navigation system.