A Wearable Haptic Device Capable of Performing Stretch Stimuli for Navigation

This paper presents a fully wearable haptic device based on skin stretching for navigation, offering a low-profile, lightweight solution for blind people. Our haptic device is able to be worn by the user in the hand for its compactness (≤ 40 mm $\times$ 40 mm $\times$ 18 mm) and its weight below 30 g. It performs skin stretch stimuli on the user palm in two directional axes through one flexible mechanism per axis leaving free the user’s fingers for common daily activities. The flexible mechanism contains a pin (end-effector) in contact with the skin that moves on a specific axis and produces the stretch stimulus. In our experimental results, the best combination of pins and working velocities for each direction in each axis were identified. For the X axis, it was pin D and pin B for left and right direction at 300 rpm, respectively. For the Y axis, it was pin D and pin C for up and down direction at 1000 rpm, respectively. Based on these results, an ideal flexible mechanism called hybrid pin mechanism was implemented to provide the stimulation achieving an 82.5% success rate in our sample of 10 healthy participants.