Enhancing the Perceived Pseudo-Torque Sensation based on the Distance between Actuators Elicited by Asymmetric Vibrations

The phenomenon of illusory pulling force, induced by asymmetric vibrations, represents a distinct perceptual experience. This pseudo-force sensation has been explored through various techniques involving the deployment of multiple vibrotactile actuators. Although these actuators can elicit multi-dimensional pseudo-forces, the impact of distance between actuators on the rotational pseudo-force (or torque sensation) remains unexplored. This study examines the influence of vibrotactile actuator distance on the pseudo-torque sensation elicited by asymmetric vibrations. We hypothesized that the distance between actuators impacts the perceived pseudo-torque in line with the principle of leverage. Our findings indicate an increase in perceived pseudo-torque up to a 50 mm separation between actuators, with an optimal distance correlating to 0.43 times the hand size for effective pseudo-torque generation. These insights are crucial for designing haptic devices capable of imparting pseudo-torque sensations.