Encoder Signal Processing Device Noise Removal and Pulse Detection

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Solution Overview

Problem

Existing encoder signal processing technologies fail to effectively remove noise signals and detect lost pulse signals, leading to erroneous detection of rotational speed and position, especially when dust attaches to the encoder's slit plate, causing noise or loss of pulse signals.

Innovation Solution

An encoder signal processing device that sets an effective detection period for pulse signal detection, generates pulse signals if not detected within this period, and uses a delay circuit to synchronize pulse signals, ensuring accurate detection and removal of noise while supplementing lost signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a digital low-pass filter is used to remove noise signals from the encoder signal, then noise removal is improved, but the ability to detect lost pulse signals deteriorates

Engineering Contradiction:
Improvenoise signalVSAvoidpulse signal detection
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The system performs preliminary action by generating a lost pulse signal before actual pulse loss occurs. The effective detection period is calculated based on the cycle of pulse signals and width of change in transport speed, allowing the system to proactively prepare for and compensate against potential pulse losses caused by dust or noise, rather than merely reacting to detected errors.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention applies beforehand cushioning by creating a compensatory lost pulse signal that serves as a buffer against future pulse losses. This pre-generated signal cushion ensures that when dust attachment or noise causes actual pulse loss, the system already has a replacement signal ready, maintaining reliable detection without requiring complex real-time error correction.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Measurement precision

If the effective detection period is set based on pulse signal cycle and transport speed change, then detection accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvepulse signal detection accuracyVSAvoiddetection period setting mechanism
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system dynamically adjusts the effective detection period by changing parameters based on real-time conditions. The detection period is calculated using the cycle of pulse signals and the width of change in transport speed, allowing the system to adapt to varying operating conditions and maintain high detection accuracy without requiring complex hardware modifications.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention implements dynamics by making the effective detection period adjustable and adaptive rather than fixed. The system continuously monitors pulse signal cycles and transport speed changes, dynamically recalculating the detection period to match current operating conditions, thereby achieving high precision without permanent complex structural changes.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution effectively removes noise signals and detects lost pulse signals, preventing erroneous detection and ensuring accurate rotational speed and position measurement, even in the presence of dust or noise, thereby improving the reliability of encoder signal processing.

Implementation Method 1

an encoder (optical rotary encoder) is widely used for detecting the amount of rotation or a rotational speed of an electric motor... irradiates a circular plate (rotating slit plate) disposed on a rotating shaft of the electric motor or a shaft to which rotational driving power of the electric motor is transmitted, with light from one side using a light emitting element such as a light emitting diode or the like. Transmitted light after the light is transmitted through the circular plate, or reflective light from the circular plate is received by a light receiving element such as a photodiode

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP3483565B1Encoder signal processing device, printer, imaging device equipped with printer, and encoder signal processing method
Publication Date: 2021.10.20 FUJIFILM CORP
  • EP3483565B1 patent drawingFigure 1~2
  • EP3483565B1 patent drawingFigure 3
  • EP3483565B1 patent drawingFigure 4

AI summary

An encoder signal processing device, a printer, a printer-equipped imaging apparatus, and an encoder signal processing method that can remove the effect of a noise signal mixed with an encoder signal and favorably deal with a case where an original pulse signal is lost from the encoder signal are provided. An effective detection period setting unit 523 sets an effective detection period for detecting a subsequent pulse signal, each time a pulse signal detection unit 522 detects a pulse signal from an encoder signal. The pulse signal detection unit 522 detects the pulse signal only within the set effective detection period. In a case where the pulse signal detection unit 522 does not detect the pulse signal within the effective detection period, a pulse signal generation unit 524 generates the pulse signal after the effective detection period.