Development of the Indoor Mobile Robot Navigating by Vision and Magnetic Tags

Abstract

We have developed an autonomous robot carrying heavy product containers, to be used in the medicine factory. In this environment, its workspace is narrow and the robot has to negotiate between existing machines and instruments. It is also necessary for the robot to comply with strict GMP standards defined by Ministry of Health, Labor and Welfare, Japan for medicine production. The paper proposes a new navigation method using both vision and magnetic tags, rather than conventional magnetic rails on the floor. The robot tows product containers on a cart, and transfers them between a packer and a palettizer for wrapping, according to the instruction given by the process controller system via infrared communication. The robot runs on defined paths by detecting either a tape on the ceiling by vision, or magnetic field generated by small magnetic tags buried on the floor. The proposed method can achieve precision equivalent to the conventional method with magnetic tapes, and requires less initial installation costs. Three robots have worked in a medicine factory for more than a year without causing a single interruption in the manufacturing process, achieving improved production efficiency, lowered production costs, with fewer workers attending the production line than before.