Automatic Map-making of Adventure-pools

Erik Magnus Andersson

Abstract

This project is about automatic mapping of irregular so called adventure type pools. It is a part of a larger project driven by the assigner, Weda, to develop a pool-cleaner robot for these kinds of pools. The robot shall be developed from the current line of pool-cleaners made for rectangular pools. Especially the robot shall be adapted to the B400 model which is the most widely sold pool-cleaner. The assigners project has been tending towards using map based positioning as a navigation method of the pool-cleaner.

The mapping algorithm uses a sonar sensor to make local map patches around the pool-cleaner, after which it makes use of a matching algorithm for matching map patches to each other. As the pool-cleaner is exploring the pool, local maps are obtained and then matched and merged to the current map so that eventually a global map is obtained. The exploring of the pool, i.e. deciding where the next scanning pose shall be, is done manually.

The sonar transducer is mounted on a stepper motor to be able to rotate one revolution and thereby make a polar local map-patch. The sonar is a standard recreational boat sonar, which has been modified by the manufacturer to fit this project. The mapping algorithm has been tested with good results in the pool at Weda and in a larger adventure pool in Fyrishov, Uppsala.