Player Piano Damper Position Detection via Lifting Rail Sensor

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Solution Overview

Problem

Existing systems face challenges in accurately recording and reproducing the positions of dampers in pianos due to discrepancies between damper pedal and damper displacement, leading to difficulties in precise control of sounding members.

Innovation Solution

A system that detects the position of the damper relative to the sounding member using a position sensor on the lifting rail, converts this data into control values, and outputs them as performance information, allowing for accurate reproduction of damper positions through a database-driven control mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sensor detects pedal positions in an ordinary piano, then the pedal positions can be recorded and reproduced, but the displacement amounts of the damper pedal and the dampers differ due to multiple component parts, making it difficult to accurately record and reproduce dumper positions

Engineering Contradiction:

Improvepedal position detection accuracyVSAvoiddumper position reproduction accuracy

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the mechanical detection system (sensor on pedal) with a database-driven system that stores and reproduces the actual dumper displacement characteristics, eliminating the need to mechanically replicate the complex transmission through multiple component parts

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a digital copy of the dumper position data by detecting actual dumper positions and storing them in a database, which can then be reproduced without physically replicating the original mechanical transmission path

Inventive Principle:

Principle #26Copying

2Ease of operation

If multiple component parts are disposed between the damper pedal and the dampers to transmit force, then the mechanism can provide the necessary mechanical advantage and control, but the displacement amounts of the pedal and dampers differ, reducing measurement accuracy

Engineering Contradiction:

Improvepedal mechanism controlVSAvoiddumper position detection accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces a database as an intermediary that stores the relationship between pedal positions and dumper positions, allowing the system to maintain the mechanical advantage of multiple component parts while achieving accurate position measurement through data mediation rather than direct mechanical measurement

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP2618328B1Musical instrument equipped with a pedal, and method therefor

Publication Date: 2016.03.30 YAMAHA CORP

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AI summary

In a player piano, a position sensor (555) is provided on an end portion of a lifting rail (8) for detecting a vertical position of the lifting rail. In storing performance data of dampers, a signal output from the position sensor and indicative of a vertical position of the lifting rail is converted into a digital signal, and a position value indicative of the position of the lifting rail is generated on the basis of the digital signal and stored into a buffer (1023). A conversion section (1021) converts the position value into a vertical position of a pedal rod connected to a damper pedal, and the thus-converted vertical position is converted into a control value which a control change message of the damper pedal in MIDI-format data can take. The control value obtained in the aforementioned manner can be recorded into a recording medium as performance information.