Abstract: A map-building scheme that uses a fuzzy system and sensors to control a wheeled mobile robotfor building a map of an unknown environment is described in this paper. This study applies aninfrared localization system and ultrasonic sensors to locate current positions and mark surroundingobstacles. With the information provided by the localization system and the distance detectedbetween the sensor and an object, a map of the surroundings can be established using a curve fittingmethod during environmental exploration. A map of an unknown environment can be built withoutusing visual sensors. Different map building approaches are applied and a comparison is given.