Yazar "Basdogan, Cagatay" seçeneğine göre listele

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    Effect of Finger Velocity on Frictional Forces Modulated by Electrovibration
    (IEEE, 2017) Sirin, Omer; Ayyildiz, Mehmet; Basdogan, Cagatay
    We investigate the effect of sliding velocity on frictional forces between human finger and a touch screen actuated by electrostatic forces. For this purpose, we command a motorized slider to move human finger back and forth (one stroke) in horizontal direction at 9 different velocities (2, 5, 10, 20, 30, 40, 50, 60, 70 mm/s) while the finger is in contact with the touch screen and record the tangential forces for the normal forces varied in a controlled manner from 0.1 N to 0.9 N. During the experiments, the electrostatic forces were turned ON and OFF after every other stroke. The results of the experiments show that the data can be categorized into two groups: 1) stickslip and 2) sliding, which occurs at velocities higher than and equal to 30 mm/s. After grouping, we fit a nonlinear function in the form of F = aF to the sliding data recorded for the OFF and ON conditions. Using the fit functions, we show that the magnitude of the electrostatic forces increases from 50 to 310 mN as the normal force is increased from 0.1 N to 0.9 N.
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    Haptic Perception of 2D Equilateral Geometric Shapes via Electrovibration on Touch Screen
    (IEEE, 2017) Sadic, Ayberk; Ayyildiz, Mehmet; Basdogan, Cagatay
    Haptic feedback is a potential technology to convey spatial, graphical, or pictorial information to visually impaired people that is difficult to be transmitted verbally. In this study, we investigated the effects of edge number (N) and rendering technique on haptic recognition of two-dimensional (2D) equilateral geometric shapes displayed by electrovibration on touch screens. We conducted experiments with 9 subjects using 5 shapes (triangle, square, pentagon, hexagon, and octagon) under 3 different experimental conditions; 1) electrovibration was displayed inside the shapes (INSIDE condition), 2) on their edges (EDGE condition), and 3) at the outside of the shapes (OUTSIDE condition). We observed that haptic recognition accuracy of the subjects decreased as the number of edges was increased from N=3 (triangle) to N=6 (hexagon). Surprisingly, the recognition accuracy for the octagon (N=8) was significantly higher than that of the hexagon. The results also showed that there was no significant difference in rendering techniques in terms of the recognition rates, but displaying electrovibration inside the shapes (INSIDE condition) led to the shortest duration of haptic recognition.