Haptic key based on a real-time multibody model of a piano action

While playing on an acoustic piano, a pianist feels an essential sensory information called the touch. Along with the sound, these two feedbacks give the musician greater control and expressivity with the instrument. Touch mainly results from the highly dynamic response of the key-to-string transmission called piano action. Present-day digital pianos offer the possibility to nuance the sound with a quite impressive quality. However, the touch feedback is not nearly as good as that of an acoustic piano keyboard. This work first presents a multibody model that allows analyzing the grand piano action behavior and understanding its functioning. In addition, experimental validation have been successfully achieved, both in kinematics and in dynamics. Secondly, a piano key prototype actuated by a custom-made linear actuator is proposed to enhance the touch of digital pianos. A multibody model computes the action dynamics in real-time, in such way that the actuator provides the same haptic feeling at the key. Rendering a grand piano action model within the haptic key prototype shows promising results and demonstrates the feasibility of our approach. This thesis highlights the interest of the multibody approach for demystifying the piano action behaviour, and for enhancing the touch of digital pianos.