Intuitive Directional Sense Presentation to the Torso Using McKibben-Based Surface Haptic Sensation in Immersive Space

In immersive spaces like virtual or mixed reality, users are often overwhelmed by visual information, making it difficult to locate specific objects or points of interest. Traditional guidance methods often rely on additional visual cues (such as arrows or highlights), which can clutter the field of view and interfere with the user's primary task. This paper proposes an alternative: using haptic sensations on the torso to guide the user's gaze indirectly by influencing their posture.

The researchers developed a wearable fabric actuator integrated with McKibben artificial muscles. By applying air pressure to these muscles, the device deforms the fabric, creating tactile sensations on the wearer's torso. The system is designed to provide four distinct kinesthetic perceptions: forward bending, backward bending, left twisting, and right twisting. These movements are intended to naturally align the user's head and eyes with a target object in the immersive space.

The core of the system is a novel air pressure adjustment algorithm. Because the relationship between air pressure and gaze angle varies, the system uses a calibration procedure based on Stevens' power law to create a mathematical model for each user. The control algorithm provides feedback only when the user's gaze deviates from the target, preventing the user from misinterpreting a decrease in haptic pressure as reaching the target destination. This ensures that the guidance remains intuitive and responsive during navigation.

The effectiveness of the system was validated through subject experiments measuring the accuracy of gaze guidance. The researchers compared different pressure adjustment methods to determine how well users could align their gaze with target objects. Finally, the system was tested in a micromanipulation scenario within a mixed-reality environment, demonstrating its potential for teleoperation tasks where precise gaze control is essential.