Speaker
Description
Active control enables the attribution of targeted temporal and spectral characteristics to vibrating structures. Applied to musical instruments, this technique allows for the production and the radiation of novel sounds throughout the interpreter's rendition, in contrast to the use of sound effects on recorded music.This study is part of a general project aiming to actively control a complex system composed of piano string triplets struck by the same hammer. For that purpose, a controller within a feedback loop is fed by the measured strings’ vibration and aims to calculate the force signal to be applied to the string triplets. Transducers composed of electromagnets are used as actuators and sensors.In this work, a model of magneto-mechanical interaction is established between the current intensity in the transducers and the vibration of a simplified model of a piano string. First, by referring to formulations derived from the Maxwell’s equations for magnetostatics, we model the magnetic field intensity created by the transducers placed near the magnetized string. Then, the modelling of the resulting force density distribution along the string is investigated using methods such as the integration of the local application of Maxwell’s stress tensor. These multi-physical models are expressed and connected using the Port-Hamiltonian Systems (PHS) formalism, which ensures the system’s passivity during simulation and control.