Evaluation of rotational and directional vibration patterns on a tactile belt for guiding visually impaired people

We present the design of a vibro tactile belt and an evaluation study of intuitive vibration patterns for providing navigation assistance to blind people. Encoding directions with haptic interfaces is a common practice for outdoor navigation assistance but it is insufficient in cluttered indoor environments where fine maneuvers are needed. We consider rotational motions in addition to directional in our application. In a usability study with 15 subjects, we evaluate the recognition accuracy and reaction times of vibration patterns that include 1) directional and 2) rotational motion. Our results show that the directional pattern of two intermittent pulses was preferred by most subjects, even though it had slightly more recognition error than patterns with continuous vibrations. Rotational patterns were recognized by subjects with almost perfect accuracy. Average reaction time to all vibration patterns varied between 1 and 2 seconds. Our tactile belt design was found comfortable, but it was also found slightly noisy.