Augmented white cane with multimodal haptic feedback

This paper proposes an instrumented handle with multimodal augmented haptic feedback, which can be integrated into a conventional white cane to extend the haptic exploration range of visually impaired users. The information extracted from the environment through a hybrid range sensor is conveyed to the user in an intuitive manner over two haptic feedback systems. The first renders impulses that imitate the impact of the real cane with a distant obstacle. In combination with the range sensors, this system allows to "touch" and explore remote objects, thus compensating for the limited range of the conventional white cane without altering its intuitive usage. The impulses are generated by storing kinetic energy in a spinning inertia wheel, which is released by abruptly braking the wheel. Furthermore, a vibrotactile interface integrated into the ergonomic handle conveys the distance to obstacles to the user. Three vibrating motors located along the index finger and hand are activated in different spatiotemporal patterns to induce a sense of distance through apparent movement. The realized augmented white cane not only increases the safety of the user by detecting obstacles from a further distance and alerting about those located at the head level, but also allows the user to build extended spatial mental models by increasing the sensing range, thereby allowing anticipated decision making and thus more natural navigation.