Rotary Shaver Motion Feedback for Large Linear Stroke Detection

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Solution Overview

Problem

Existing rotary shaver feedback systems fail to differentiate between unavoidable small linear motions and avoidable large linear motions, leading to inaccurate feedback that can distract users and reduce shaving performance.

Innovation Solution

A method and apparatus that utilize motion shape and size detection to provide differentiated feedback, distinguishing between large, avoidable linear motions and small, unavoidable motions, using a processing unit to generate feedback signals based on motion data from a sensor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If feedback is provided for all linear motions, then user guidance on proper shaving technique is improved, but user distraction increases and shaving performance deteriorates

Engineering Contradiction:
Improvefeedback accuracyVSAvoiduser distraction
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent applies local quality by providing differentiated feedback based on motion characteristics. Instead of uniform feedback for all linear motions, the system selectively provides feedback only for large linear motions that can be improved, while acknowledging small linear motions as unavoidable. This localized approach to feedback improves accuracy without causing user distraction.

Inventive Principle:
Principle #3Local quality

2Productivity

If motion feedback is provided to guide users, then shaving performance is improved, but feedback complexity increases

Engineering Contradiction:
Improveshaving performanceVSAvoidfeedback system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments feedback into different types based on motion characteristics. The processing unit analyzes motion data and generates different feedback signals for different motion types (circular vs. linear, small vs. large). This segmentation allows the system to provide comprehensive guidance without overwhelming complexity, as each motion type receives appropriate targeted feedback.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If all linear motions are corrected, then shaving technique improvement is maximized, but skin irritation increases due to excessive feedback

Engineering Contradiction:
Improveshaving technique precisionVSAvoidskin irritation
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent changes the parameter of feedback provision from binary (feedback or no feedback) to conditional (feedback based on motion size and type). By introducing size thresholds and motion type classification, the system provides feedback only when necessary (for large linear motions), avoiding excessive feedback that could cause skin irritation while still improving shaving technique precision.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4699752A1Method and apparatus for controlling feedback regarding motion of a rotary shaver performed by a user
Publication Date: 2026.02.25 KONINKLIJKE PHILIPS NV
  • EP4699752A1 patent drawingFigure 1(a)
  • EP4699752A1 patent drawingFigure 1(b)
  • EP4699752A1 patent drawingFigure 1(c)

AI summary

The present invention relates to a method (100) of controlling feedback to a user regarding motion of a rotary shaver performed by the user, the method comprising the steps of: obtaining motion data from a motion sensor (12) monitoring the motion of the rotary shaver (8) performed by the user; determining shape and size of the monitored motion based on the obtained motion data, the shape indicating if the monitored motion is circular or linear; and generating a control signal configured to trigger feedback of a first type to the user if the monitored motion is determined to be a linear motion having a size above a threshold and to trigger feedback of another type, different from the first type, to the user if the monitored motion is determined to be a circular motion or a linear motion having a size equal to or below the threshold.