Robot obstacle detection system

DETAILED DESCRIPTION It is therefore an object of this invention to provide a robot obstacle detection system which is simple in design, low cost, accurate, easy to implement, and easy to calibrate.
It is a further object of this invention to provide such a robot detection system which prevents an autonomous cleaning robot from driving off a stair or obstacle which is too high.
It is a further object of this invention to provide a robotic wall detection system which is low cost, accurate, easy to implement and easy to calibrate.
It is a further object of this invention to provide such a robot wall detection system which effects smoother robot operation in the wall following mode.
It is a further object of this invention to provide a sensor subsystem for a robot which consumes a minimal amount of power.
It is a further object of this invention to provide a sensor subsystem which is unaffected by surfaces of different reflectivity.
The invention results from the realization that a low cost, accurate, and easy to implement system for either preventing an autonomous cleaning robot from driving off a stair or over an obstacle which is too high or too low and/or for more smoothly causing the robot to follow a wall for more thorough cleaning can be effected by intersecting the field of view of a detector with the field of emission of a directed beam at a predetermined region and then detecting whether the floor or wall occupies that region.
If the floor does not occupy the predefined region, a stair or some other obstacle is present and the robot is directed away accordingly.
If a wall occupies the region, the robot is first turned away from the wall and then turned back towards the wall at decreasing radiuses of curvature until the wall once again occupies the region of intersection to effect smoother robot operation in the wall following mode.
This invention features an autonomous robot comprising a housing that navigates in at least one direction on a surface.
A first sensor subsystem is aimed at the surface for detecting obstacles on the surface