A Detection System of Location and Direction Angle by a RF Tag Reader Using a Rotary Antenna

This paper describes the method of presuming the angle of moving direction of an electric wheelchair by reading information of RF tags put on a floor using a rotary antenna, which is fixed underneath the wheelchair, revolving constantly above RF tags of the floor at a turning point. Our primary intention is to make a detection system of direction angle using RF tags for a voice controlled electric wheelchair. The voice instruction cannot give smooth nor detailed controls with ease unlike the joystick control. Because the voice control system can use only a few discrete instruction words. Thereby to assist smooth indoor motion, we proposed here a new method of automatic correction of the direction angle measured by the above rotary antenna and RF tags. We demonstrated experimentally to detect and correct the angle of moving direction when the wheelchair passes over the turning point, which was found to give accurate orientations.(1)