Keyboard Apparatus Velocity Control for Smooth Touch Response

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Solution Overview

Problem

Conventional electronic musical instrument keyboards with graded hammer mechanisms face challenges in achieving smooth touch response due to mechanical deviations and stepwise weight changes, leading to decreased player satisfaction.

Innovation Solution

A software-controlled keyboard apparatus that detects key depression position and velocity, using velocity generation rules to correct reaction forces and provide a smooth, graded touch response across all keys, eliminating mechanical control and deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a graded hammer mechanism is used to provide different weights for keys, then the touch response weight distribution is improved, but mechanical deviations and stepwise weight changes occur causing poor touch response smoothness

Engineering Contradiction:

Improvekey weight distributionVSAvoidtouch response consistency

Core Design Contradiction:

Weight of moving objectVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical graded hammer system with a software-based velocity generation system. Instead of physically varying hammer weights to achieve graded touch response, the system uses uniform hammers combined with software algorithms that calculate and adjust velocity based on key position and depression characteristics, thereby eliminating mechanical deviations while maintaining graded touch response.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the control parameter from physical hammer weight to velocity generation parameters. By using velocity generation rules that adjust the velocity parameter based on key position (lower velocity for lower notes, higher velocity for upper notes) and depression characteristics, the system achieves graded touch response without the manufacturing precision problems of physical weight variation.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If multiple hammer types are used to achieve gradual weight changes, then the touch response gradient is improved, but the number of mechanical parts and complexity increase

Engineering Contradiction:

Improvetouch response gradientVSAvoidmechanical parts quantity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent eliminates the need for multiple hammer types by substituting the mechanical system with a software-based velocity control system. A single uniform hammer design is used for all keys, and the graded touch response is achieved through software velocity generation rules that calculate appropriate velocities based on key position and depression characteristics, significantly reducing mechanical complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent makes the hammer design universal by using the same hammer for all keys regardless of note position. The velocity generation system then provides the necessary differentiation in touch response through software control, allowing one hammer design to serve all functional requirements across the keyboard.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of manufacture

If keys are grouped with identical hammers to simplify manufacturing, then ease of manufacture is improved, but stepwise weight changes occur between groups creating noticeable steps

Engineering Contradiction:

Improvehammer productionVSAvoidtouch response continuity

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent replaces the mechanical grouping strategy with a software-based velocity adjustment system. Instead of physically grouping keys with identical hammers and accepting the resulting stepwise changes, the system uses uniform hammers combined with velocity generation rules that continuously adjust velocity based on key position, eliminating steps while maintaining ease of manufacture.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses parameter changes in the velocity generation rules to compensate for the simplified manufacturing approach. By adjusting the velocity parameter continuously based on key position (lower velocity for lower notes, higher velocity for upper notes) and depression characteristics, the system achieves smooth touch response transitions without the need for complex mechanical groupings.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS7750231B2Keyboard apparatus of electronic musical instrument

Publication Date: 2010.07.06 YAMAHA CORP

AI summary

A keyboard apparatus of this electronic musical instrument is provided with touch curves TW1 through TWp, TB1 through TBq each defining a velocity value Vc varying with a key-depression velocity Kv (TD). Each of keys K1 through Kn of a keyboard 14k is associated with one of the touch curves TW1 through Twp, TB1 through TBq by touch selecting tables SW, SB in accordance with an equalization rule and a weighting rule. Upon a key-depression, in accordance with the velocity curve TWr, TBs selected on the basis of an actual depressed key position Ki (M2), an actual key-depression velocity Kva is converted into a velocity Vca for controlling emission of a tone (M3).