First validation of the Haptic Sandwich: a shape changing handheld haptic navigation aid

This paper presents the Haptic Sandwich, a handheld robotic device that designed to provide pedestrian navigation instructions through a novel shape changing modality. The device resembles a cube with an articulated upper half that is able to rotate and translate (extend) relative to the bottom half, which is grounded in the user’s hand when the device is held. The poses assumed by the device simultaneously correspond to heading and proximity to a navigational target. The Haptic Sandwich provides an alternative to screen and/or audio based pedestrian navigation technologies for both visually impaired and sighted users. Unlike other robotic or haptic navigational solutions, the haptic sandwich is discrete in terms of form and sensory stimulus. Due to the novel and unexplored nature of shape changing interfaces, two user studies were undertaken to validate the concept and device. In the first experiment, stationary participants attempted to identify poses assumed by the device, which was hidden from view. In the second experiment, participants attempted to locate a sequence of invisible navigational targets while walking with the device. Of 1080 pose presentations to 10 individuals in experiment one, 80% were correctly identified and 17.5% had the minimal possible error. Multi-DOF errors accounted for only 1.1% of all answers. The role of simultaneous or independent actuator motion on final shape perception was tested with no significant performance difference. The rotation and extension DOF had significantly different perception accuracy. In the second experiment, participants demonstrated good navigational ability with the device after minimal training and were able to locate all presented targets. Mean motion efficiency of the participants was between 32%-56%. Participants made use of both DOF