Automatic player piano with touch strength estimator

A key touch estimation system provided in association with a mechanical piano having a keyboard provided with a plurality of keys respectively depressed with forces by a player, a key action mechanism coupled to said keyboard for transmitting the forces exerted on said keys, a hammer mechanism provided with a plurality of hammer assemblies, said hammer assemblies being coupled to said key action mechanism and driven for rotations with the forces transmitted by said key action mechanism, and a plurality of music wires respectively struck with said hammer assemblies for producing sounds, said key touch estimation system comprising

• (a) a controller operative to memorize pieces of key touch information respectively representative of grades of intensity assigned to said sounds in said recording mode of operation and retrieve the pieces of the key touch information in said playback mode of operation,
• (b) a plurality of actuators provided in association with said keyboard and responsive to the pieces of said key touch information for causing said keys to move,
• (c) a sensor unit provided in association with said keyboard and operative to detect key motion of said keys for producing the pieces of said key touch information in said recording mode of operation,
• (d) tracing means operative produce loci of said key motions,
• (e) sampling means operative to extract sections for uniform motions from said loci, respectively,
• (f) key velocity calculating means operative to decide key velocities in said sections, respectively,
• (g) final hammer velocity deciding means operative to estimate final velocities of said hammer assemblies on the basis of said key velocities, respectively, and
• (h) key touch information producing means operative to produce the pieces of said key touch information on the basis of said final velocities, respectively.