Ball-type Haptic Interface to Present Impact Points with Vibrations for Televised Ball-based Sporting Event

We propose a ball-type haptic interface that presents both impact vibration and impact points to reproduce the impact between the ball and hitting object (e.g. racket, bat, hand, or foot) in a ball game. Impact vibration is presented using one vibro-transducer, and the points are presented by simply denting one of the eight points of a Polyurethane ball surface using four servo motors. An experiment was conducted to clarify the perceptual characteristics when a dent point was presented along with intense vibration of three different frequencies (30, 80, and 250 Hz). Most participants could detect the dented points in the case along with 250 Hz vibration. The mean correct answer rate decreased approximately 40 percent with 30 Hz vibration compared to 250 Hz, especially with three different areas on the palm. The results suggest that there is a significant masking effect between vibration and pressure sensation on the palm. Finally, some applications and design improvements are discussed to present impact points with impact vibrations for televised ball-based sporting events.