Relationship between perceived maneuverability and compensatory eye movements under systematically varied time constants of ride-on machinery.

Studies suggest that the vestibulo-ocular reflex (VOR), which is one of compensatory eye movements, exhibits greater stability during active motion compared to passive motion, and this effect may also apply to the operation of ride-on machinery. Moreover, one study suggested that experimentally manipulating the sense of agency (SoA), such as by introducing delays, can influence the stability of such eye movements. Although a preliminary investigation examined compensatory eye movements and perceived maneuverability under two distinct machine dynamics with a preserved SoA, it remains unclear how systematic variations in motion dynamics influence these factors. Therefore, this study aimed to investigate whether systematic variations in the dynamic properties of a ride-on machine, for which perceived maneuverability is modulated, influence the accuracy of operators' eye movements, focusing on continuous compensatory components, including visually enhanced VOR. Participants rode a yaw-rotational platform whose time constant from joystick input to motor torque was systematically manipulated. During the operation, eye movements were recorded while participants fixated on a visual target fixed to the Earth. After each condition, participants reported their perceived maneuverability and cognitive load. As the platform's time constant increased, maneuverability scores decreased, whereas cognitive load increased. Concurrently, the velocity accuracy of compensatory eye movements decreased. Perceived maneuverability was positively correlated with eye velocity gain and negatively correlated with velocity error. These findings suggest that perceived controllability and eye velocity accuracy are closely related under varying machine dynamics and that this relationship may inform the design of high-maneuverability ride-on machinery.