Behavior of piano-action in a grand piano. I. Analysis of the motion of the hammer prior to string contact

Producing a stable soft tone, difficult even for pianists, is one of the critical challenges in the development of an automatic piano. The motion of the hammer prior to string contact was studied to provide a basis for creating a stable, soft tone. A simple dynamic mechanical model was used to analyze the motion. Using the actuator developed for the touch system, the motion of the hammer under various input waveforms was observed and recorded. Based on this analysis, it can be said that the calculated behavior correlates with the measured behavior. These results indicate that the proposed model is useful because it clearly illustrates the behavior of the hammer. The modified constant speed necessary to produce an optimum touch input waveform has now been found, which allows the system to achieve stable soft tones.