Mobile robot relocation using echolocation constraints

Presents a technique for relocation of a mobile robot using sonar data. Relocation is the process of determining the position and orientation of a mobile robot with respect to the global reference frame in situations where no a priori estimate of the robot´s location is available. A two dimensional model of the environment is employed consisting of planes, corners, edges, and cylinders. A physically based sonar sensor model is used to characterize the geometric constraints provided by echolocation measurements of different types of objects. The sensor model makes it possible to employ individual range returns as data features in a constraint-based search to determine the robot´s position. To increase the efficiency of search, a hypothesize and verify technique is employed in which position of the robot are calculated from all possible combinations of two range returns that satisfy the measurement model. Accurate relocation is demonstrated from sparse sonar data in the presence of unmodeled objects