Dynamic characterization of grand and upright piano action

A dynamic characterization was performed on a grand piano and an upright (vertical) piano action assembly. The action assembly consists of a key and a system of levers that transfers a force from the key to the hammer. Measurements of the hammer acceleration profile for a given key force were compared to dynamic simulation results from a computer model constructed in SolidWorks. Single-key action assemblies typically used by piano technicians were used for the dynamic measurements and as a guide for the physical dimensions of the computer model. Measurements of hammer velocity were made using a Laser Doppler Vibrometer, which was differentiated to determine the hammer acceleration. The purpose of the study was to establish a relationship between key force and hammer acceleration for the action assemblies and to construct a computer model whose dynamic behavior closely matches the measured profile. Preliminary results between the measured hammer acceleration and the simulated acceleration will be discussed. [Work supported by a University of Hartford CETA Student Engagement Grant.]