METHOD AND APPARATUS FOR SIMULTANEOUS LOCALIZATION AND MAPPING OF MOBILE ROBOT ENVIRONMENT

摘要

Techniques that optimize performance of simultaneous localization and mapping (SLAM) processes for mobile devices, typically a mobile robot. In one embodiment, erroneous particles are introduced to the particle filtering process of localization. Monitoring the weights of the erroneous particles relative to the particles maintained for SLAM provides a verification that the robot is localized and detection that it is no longer localized. In another embodiment, cell-based grid mapping of a mobile robot's environment also monitors cells for changes in their probability of occupancy. Cells with a changing occupancy probability are marked as dynamic and updating of such cells to the map is suspended or modified until their individual occupancy probabilities have stabilized. In another embodiment, mapping is suspended when it is determined that the device is acquiring data regarding its physical environment in such a way that use of the data for mapping will incorporate distortions into the map, as for example when the robotic device is tilted.

主权项

1. A mobile device tracking system comprising:
a. apparatus that generates a map of the device's physical environment, said generating occurring either concurrently with or prior to tracking the device's position, said generating apparatus updating said map either concurrently with or prior to tracking the device's position; and b. a processing apparatus to determine the device's current location within said map by generating position and/or orientation particles, each of said position and/or orientation particles representing a potential position and/or orientation of the device within its physical environment, wherein a data set of said position and/or orientation particles may be generated and maintained iteratively to track changing position of the device within its physical environment, c. the processing apparatus including:
i. apparatus that assigns a weight to each position and/or orientation particle, particle weight being a relative measure of the particle's likelihood of accurately representing the robot's position with respect to other position and/or orientation particles;ii. apparatus that introduces erroneous particles whose potential positions are selected so that their assigned weights should be uniformly low with respect to the weights of the position and/or orientation particles; andiii. apparatus that compares the weights of the erroneous particles and the weights of the position and/or orientation particles to determine whether the mobile device has become delocalized when a substantial number of erroneous particles have weights that are no longer uniformly low with respect to the weights of the position and/or orientation particles.