Positive and negative obstacle avoidance system and method for a mobile robot

Abstract

Embodiments of the present invention provide methods and systems for ensuring that mobile robots are able to detect and avoid positive obstacles in a physical environment that are typically hard to detect because the obstacles do not exist in the same plane or planes as the mobile robot's horizontally-oriented obstacle detecting lasers. Embodiments of the present invention also help to ensure that mobile robots are able to detect and avoid driving into negative obstacles, such as gaps or holes in the floor, or a flight of stairs. Thus, the invention provides positive and negative obstacle avoidance systems for mobile robots.

Description

FIELD OF ART[0001]This invention generally relates to mobile robots. More specifically, the invention is directed to systems and methods for detecting positive and negative obstacles in physical environments through which mobile robots move and preventing the mobile robots from driving into those obstacles.BACKGROUND ART[0002]Mobile robots, including autonomously-navigating mobile robots, inertially-guided robots, remote-controlled mobile robots, and robots guided by laser targeting, vision systems, roadmaps and beacons, to name a few examples, normally use horizontally-oriented laser sensors to scan the area in the mobile robot's direction of travel and to detect potential obstacles in the mobile robot's path. The horizontally-oriented lasers, which typically scan in two-dimensional planes roughly parallel with floor, work reasonably well for detecting objects that extend from the floor in a substantially perpendicular direction, so long as the obstacle intersects the horizontally-...

AI Technical Summary

Benefits of technology

The present invention provides a negative obstacle avoidance system for mobile robots in physical environments. This system prevents the robot from driving into gaps, holes, or off of cliffs by using a tolerance profile to compare non-horizontally-oriented laser readings with a floor distance readings. The system also reduces false positives and avoids driving into safe gratings or small gaps in the floor. The system allows the robot to operate safely and efficiently in its physical environment.

Problems solved by technology

However, they do not work well for detecting positive physical obstacles in the mobile robot's path that are parallel to the floor and / or obstacles that are not at the same height as the horizontally-oriented scanning plane.

This means the mobile robots frequently have no way of detecting and avoiding positive obstacles, such as long tables with legs at the ends (and no legs in the middle), objects suspended from a ceiling or other structure, and obstacles that stick out from the edge of another object, like a keyboard tray.

Mobile robots that use horizontally-oriented lasers for detecting obstacles also have problems detecting and avoiding unexpected negative obstacles, such as a hole in the floor, a descending flight of stairs, the end of a loading dock or the edge of a cliff.

However, there have been a number of significant disadvantages associated with such solutions, including prohibitively-high cost associated with installing, using and maintaining a multiplicity of expensive lasers, and an unacceptably high number of false positives arising, for example, from gratings in the floor, which do not necessarily need to be avoided by the mobile robot.

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