Figure 5
Presentation of the stimuli for the 4 gradient values (from top to bottom of the figure) under the 60 mm window condition with 3 types of measures. The left figures present the amplitude command of the modulating signal, the center present the measured vibration of the glass plate and the right present the measured friction coefficient between the finger and the surface. The amplitude is attenuated for higher frequencies to equalize the perceived intensity of the stimuli. Friction measurements are performed with a sensor described in a previous work52.
