In the guidance systems for a mobile robot, free-path-type guidance system does not need a hardwired path in the environment so that it gives a mobile robot a flexible path.
In this study, to achieve the free-path-type guidance system for a mobile robot which is steered by the differential steering of both drive forewheels, position recognition systems are constructed using odometer system as a internal position sensor.
Two odometer systems, a auxiliary wheel odometer and a 2-encoder odometer system are constructed and path following algorithms using these dometer systems are composed and experimented. PID control type is adopted in the path following algorithms.
The experimental results of this study are as follows: maximum lateral deviation is 4 cm/m in the aux. wheel odometer system and 2.5 cm/m in 2-encoder odometer system. With maximum initial deviations of 70 cm in lateral and 140˚ in direction, the mobile robot is able to follow a given straight path. In experiment of path following, the mobile robot is able to follow the given path within lateral deviation of 25cm.
As a summary, this study shows that a practically applicable range of a path can be followed by using odometer system.
