Elasto-plastic friction modeling toward reconstructing measured bowed-string transients

Abstract

Physical modeling may be used to simulate the motion of a vibrating string under frictional excitation by a bow. This study compares the measured transient behavior of a bowed string with predictions from a physics-based simulation that assumes a finite-width bow, incorporates bow-hair compliance, considers the string's torsional motion, and utilizes an elasto-plastic friction model. The model is first evaluated by comparing simulated Guettler playability diagrams to a measured diagram obtained from a robot arm bowing a monochord. The playability regions are qualitatively similar, but some significant differences in the underlying waveforms are not captured. In order to improve the reconstructions of individual waveforms, inverse modeling is employed to derive parameter values for the elasto-plastic friction model, demonstrating the ability to generate accurate reconstructions of measured signal transients. The findings highlight the importance of accounting for variable friction coefficients that change with bow force and bow acceleration. This observation is consistent with prior research indicating that static and dynamic friction coefficients vary within a Guettler diagram.