A Biologically Inspired Sensor Mechanism for Amplification of Tactile Signals Based on Parametric Resonance

In this paper, the vibrational motion of an elastic beam under the parametric excitation is investigated theoretically and numerically. The problem is motivated by biological tactile sensors, called vibrissae or whiskers. Mammals use these thin long hairs for exploration of the surrounding area, object localization and texture discrimination. We propose a mechanical model of the vibrissa sweeping across a rough surface as a straight truncated beam stimulated by a periodic following force. The equation of transverse motion of the beam is studied using the Euler–Bernoulli beam theory and asymptotic methods of mechanics. The numerical analysis is performed by means of the finite element method. It is shown that the parametric resonance of the beam occurs at the specific ranges of the excitation frequency, which depend on the parameters of the beam and the amplitude of the applied force. For these frequency values, the vibrations of the beam are unstable with exponentially increasing amplitude. The comparison of the resonance ranges obtained theoretically and numerically is made. Thus, together with the realisation of the viscoelastic support of an artificial tactile sensor, the parametric resonance may be a potentially useful method for amplifying small signals arising from the contact with an object.