Evaluation of a friction reduction based haptic surface at high frequency

Abstract

The influence of the vibration frequency on the friction reduction of an ultrasonic haptic surface has been reported in the literature. The models predict that increasing the frequency of the vibration leads to higher friction reduction at constant vibration amplitude, but this has not been reported experimentally. In this paper, we study the friction reduction on a prototype which can vibrate at low (66kHz) and high (225kHz) frequency. By estimating the Point of Subjective Equivalence between a standard at low frequency with a sample at high frequency, we have found that high frequencies can indeed reduce the friction, with the advantage of much smaller vibration amplitude. Moreover, we show that the invariant between the two frequency conditions is not the vibration amplitude. Our conclusion is that the invariant could be the acceleration instead.

How the Mechanical Properties and Thickness of Glass Affect TPaD Performance

“…where the α, p 0 , u 0 , and p s are the vibration amplitude of the plate, the atmospheric pressure, the gap at rest, and the pressing pressure, respectively. Although the model showed good fit with the results from human fingers and an artificial finger, it did not consider the effect of vibration frequency, which was shown to be an important factor in [13], [15], [16].…”

“…where U , f , α, µ 0 , ν, and Ψ * are finger exploration velocity, vibration frequency, vibration amplitude, friction coefficient when the ultrasonic vibration is off, and the characteristic value of Ψ. Additionally, Giraud, et al [16] investigated the friction reduction on a vibrating plate at 66 kHz and 225 kHz. Both the friction measurements and psychophysical results showed that the ultrasonic friction reduction depended on the plate's acceleration.…”

“…The model of Vezzoli,et al and Sednaoui,et al [13], [15] showed good agreement with experimental results in which the vibration frequencies were 10 kHz to 100 kHz and the vibration amplitudes were larger than 1 µm. The experiments of Giraud, et al [16] compared only two vibration frequencies (66 kHz and 225 kHz).…”

Estimating Friction Modulation From the Ultrasonic Mechanical Impedance

“…The mechanical behavior of skin has been extensively studied in the low-frequency end of the spectrum, where skin behaves mostly as an overdamped spring and damper system [24], [25], [26], [27] but little is known about the behavior in the ultrasonic range. Some models use a mass, spring, and damper series to capture the complex dynamics [28]. Recent measurements that rely on the self-sensing capabilities of ultrasonic friction modulation devices showed that skin behaves as a mass of ≈0.1 g in parallel with a damper of ≈20 N.s/m in the 30 to 40 kHz range [8].…”

Phononic Crystals Applied to Localised Surface Haptics

“…A main design challenge in metamaterials is to tune band gaps to the desired carrier frequencies. For the application at hand, the band gaps should be set between 30 kHz and 225 kHz [20] in thin plates made of materials and dimensions relevant to surface haptics.…”