Outdoor Pedestrian Navigation Assistance with a Shape-Changing Haptic Interface and Comparison with a Vibrotactile Device

By targeting haptic sensory channels when walking, pedestrian navigation systems (as found in smartphone apps) have the potential to allow both visually impaired and sighted users to pay greater attention to their surroundings, compared to typical audio or visual based feedback. In line with this idea, we have proposed mechanotactile shape-changing interfaces as an alternative to the more commonly used haptic modality of vibrotactile feedback. In this paper, we evaluate the potential for haptic guidance in a realistic outdoor navigation task. Participants were guided along pre-determined footpath routes in similar to 3,500m(2) outdoor public environment, via 'equivalent' handheld shape-changing and vibrotactile feedback devices, capable of providing heading and proximity information. Localization was based on real-time GPS data provided by a smartphone. Many other pedestrians (not part of the study) shared the space and had to be avoided, as in typical urban settings. All participants located all waypoints with both devices, walking between 270m-600m per trial. Walking efficiency was similar for both devices, though participants took over twice as long (on average) to complete the routes with the vibrotactile device. In a questionnaire, participants preferred the shape-changing interface, considering it more intuitive and pleasant to use than the vibrotactile system. Though haptics can certainly be used for practical navigation, the relatively low resolution of unprocessed GPS positioning can lead to erroneous instructions that are harder for a (sighted) user to notice and correct than in screen based systems utilizing visual maps.