Keyboard Musical Instrument Approach Sensing and Force Control
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Solution Overview
Problem
Conventional electronic piano systems cause a delay in applying external force to keys, resulting in a uniform touch sensation for both fortissimo and pianissimo playing, which is perceived as strange by skilled players, as they sense physical quantities only after key depression and apply force accordingly.
Innovation Solution
The system senses a player's finger approach and applies an external force before key depression, using sensors to detect distance, velocity, and acceleration, allowing the controlling portion to adjust the force magnitude based on approach velocity and finger mass, and varying force application according to key type and pitch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the system senses physical quantities after key depression and applies external force accordingly, then the control system operates with simple sensing mechanisms, but the key touch sensation becomes delayed and uniform for both fortissimo and pianissimo playing
Solution Approach 1:
The system performs preliminary sensing of finger approach (distance, velocity, acceleration) before the finger actually touches the key. The controlling portion calculates the required external force in advance based on these approach parameters and applies it before key depression occurs, eliminating the delay between sensing and force application while maintaining realistic key touch sensation.
Solution Approach 2:
The system applies an opposing external force to the key before the finger touches it, based on predicted finger approach characteristics. This preliminary counter-force prevents the key from moving naturally toward the finger, creating the desired resistance sensation that mimics acoustic piano behavior while accounting for the player's intended playing dynamics.
2Reliability
If the system applies external force after key depression starts, then the control logic remains simple, but skilled players perceive the key touch as strange because fortissimo and pianissimo touches become indistinguishable
Solution Approach 1:
The system dynamically adjusts the magnitude of external force applied to the key based on real-time finger approach characteristics (velocity, acceleration, mass). For fortissimo playing with high approach velocity, a larger external force is applied; for pianissimo playing with low approach velocity, a smaller external force is applied. This dynamic adaptation preserves the natural relationship between playing intensity and key resistance.
Solution Approach 2:
The controlling portion changes the parameter of external force magnitude based on sensed finger approach parameters. By continuously monitoring finger velocity and acceleration before key contact, the system adjusts the applied force parameter to match the player's intended dynamics, ensuring that fortissimo and pianissimo touches produce distinctly different and realistic key sensations.
Data Source
AI summary
An approach of a finger of a player to a key in order to conduct an operation for playing music is sensed to exert an external force which resists a depression of the key before the finger whose approach has been sensed touches the key. As a result, the touch feeling of keys of an acoustic piano perceived by a player right after depressions of the keys is realized.