On the 1/f noise and non-integer harmonic decay of the interaction of a finger sliding on flat and sinusoidal surfaces

Fluctuations of the frictional force arising from the stroke of a finger against flat and sinusoidal surfaces are studied. A custommade high-resolution friction force sensor, able to resolve millinewton forces, was used to record those fluctuations as well as the net, low-frequency components of the interaction force. Measurements show that the fluctuations of the sliding force are highly non-stationary. Despite their randomness, force spectra averages reveal regularities. With a smooth, flat, but not mirror-finish, surface the background noise follows a 1/ f trend. Recordings made with pure-tone sinusoidal gratings reveal complexities in the interaction between a finger and a surface. The fundamental frequency is driven by the periodicity of the gratings and harmonics follow a non-integer power-law decay that suggests strong nonlinearities in the fingertip interaction. The results are consistent with the existence of a multiplicity of simultaneous and rapid stick-slip relaxat...

• Type: Journal
• Year: 2011
• Where: HAPTICS
• Authors: Michael Wiertlewski, Charles Hudin, Vincent Hayward
• Keywords: Force Spectra Averages, Frictional Force, HAPTICS 2011, Human Computer Interaction, Pure-tone Sinusoidal Gratings