Multibody Model of a Grand Piano Action Aimed at Understanding and Demystifying the Escapement Principle

The present project has been achieved in close collaboration with the MIM, the Musical Instruments Museum of Brussels. Thanks to our multibody modeling and analysis capabilities, we have carried out a virtual demonstrator of a grand piano action in order to understand, explain and demystify the functioning of the “from key-to-string” transmission, and especially the single and double escapement principle. The developed demonstrator takes advantage of multibody dynamics as well as of an experimental set up to analyze this highly dynamic system. Our work is based on previous mathematical models available in the literature but also on the large expertise of our collaborators at the MIM, for piano action tuning and for the historical aspects relating to this instrument. In this paper, we highlight the main issues and outcomes of the project – namely the multibody modeling of a grand piano action together with the experimental validation – and some key results related to the tuning of the aftertouch and the double escapement principle.