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Home | Seminars and Symposia | Past seminars/symposia: Tuesday, January 17, 2012

DTC Seminar Series

Cooperative Localization and Mapping in Sparsely-Communicating Robot Networks — The Centralized-Equivalent Approach


Keith Leung

Tuesday, January 17, 2012
10:30 am

402 Walter Library

LeungMulti-robot systems are essential in tasks that require simultaneous presence or actions. In many of these tasks, it is necessary for robots to estimate the poses (i.e., position and orientation) of other robots in the team, as well as estimate a map of the operating environment. Cooperation and the sharing of information between robots allow for performance gains in conducting simultaneous localization and mapping (SLAM). However, maintaining a persistent communication network may not be feasible due to environmental factors and hardware limitations. Under the assumption that the communication network may never be fully connected, the centralized-equivalent approach is a novel decentralized method that allows all robots in a team to obtain estimates of all robot poses and the map by recursive filtering. In this talk, we will review this centralized-equivalent approach, which allows robots to obtain the same estimates as the ones produced if the network was fully connected. This approach does not require each robot to keep track of the information known to other robots, thus allowing each robot to individually discard information through the Markov property assumption. Furthermore, to make better use of the computational resources available in a multi-robot team, the evaluation of estimates based on different data association hypotheses can be distributed using the centralized-equivalent approach. As part of this talk, we will also examine some of the validation results from hardware experiments, which were conducted using a fleet of robots in an indoor environment. After the main talk on cooperative SLAM, we will briefly go over a recent lunar sample-return analogue mission conducted over the summer of 2011 by the Autonomous Space Robotics Lab at the University of Toronto.


Keith Leung received his B.A.Sc. degree in Mechanical Engineering from the University of Waterloo in 2005. He then joined the Lab for Autonomous and Intelligent Robotics at the University of Waterloo as a graduate student, and received his M.A.Sc. degree in 2007. Following this, Keith continued his graduate studies at the University of Toronto Institute for Aerospace Studies (UTIAS), where he is currently a member of the Autonomous Space Robotics Lab (ASRL), and the Flight Systems Control (FSC) Lab. Recently, in November 2011, Keith successfully defended his Ph.D. thesis.