Collision-Free Navigation Using Laser Scanner and Tablet Computer for an Omni-Directional Mobile Robot System with Active Casters

A novel mobile system for effective object transportation was developed in this paper. By installing the proposed multiple double-wheel-type active casters to an object, the system itself becomes an omni-directional mobile robot that can be controlled with a tablet computer in a teleoperation manner. Each active caster was designed as an independent module having a micro-computer to control motors of both wheels; a Bluetooth communication component to connect with a tablet computer; a battery as a power source and so on. The operator's command for the desired motion of the main platform is transformed into an appropriate velocity command for each wheel based on the kinematic relationship between the object and the wheel coordinates. Collision avoidance navigation algorithm with a laser scanner attached to the object and a user interface with a tablet computer are also proposed for safe usage in real fields. The developed system and the collision avoidance algorithm were demonstrated through experiments.