Slip Ring Encoder Redundant Sensor Signal Stability

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Solution Overview

Problem

Conventional slip ring encoders experience instability and output errors due to blocked holes on the encoding belt, leading to erroneous differential pulse signals and abnormal equipment operation, particularly from dust accumulation.

Innovation Solution

An encoder with a redundant sensor system that generates a redundant sense signal, which is combined with the primary sense signal using a logical OR gate to produce a stable encoded signal, reducing the impact of external interference and ensuring accuracy and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single sensor is used to generate sense signals from the encoding belt, then the device complexity is low, but the reliability deteriorates due to blocked holes causing erroneous signals

Engineering Contradiction:
Improvesignal stabilityVSAvoidsensor system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by providing redundant sensors before the encoding belt holes can be blocked by dust. The redundant sensors are positioned to detect the same encoding features, so when dust blocks one sensor's view, the redundant sensor already has the capability to provide backup detection, preventing signal errors before they occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements copying by creating redundant copies of the sensing function. Multiple sensors are positioned to detect the same encoding belt features, generating duplicate sense signals. This copying approach ensures that if one sensor fails or is blocked, identical backup signals are available to maintain reliable operation.

Inventive Principle:
Principle #26Copying

2Reliability

If the encoding belt operates for a long time without maintenance, then productivity is maintained, but the reliability deteriorates due to dust accumulation blocking holes

Engineering Contradiction:
Improveoutput signal accuracyVSAvoidcontinuous operation time
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The redundant sensor system provides preliminary protection against dust accumulation effects. By having backup sensors in place before dust blocking occurs, the system can maintain reliable operation throughout extended continuous operation periods without requiring frequent maintenance or signal accuracy degradation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the system's redundancy parameter by introducing additional sensors. This parameter change allows the system to tolerate dust accumulation and blocked holes during prolonged operation, maintaining signal accuracy without requiring maintenance interruptions.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If redundant sensors are added to correct blocked hole errors, then reliability improves, but the device complexity increases

Engineering Contradiction:
Improveequipment operation stabilityVSAvoidsignal processing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses copying to simplify the approach to reliability. Instead of complex error correction algorithms, it simply copies the sensing function with redundant sensors that generate duplicate signals. This copying strategy improves reliability while keeping the added complexity minimal and straightforward.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent changes the redundancy parameter by adding backup sensors rather than implementing complex signal processing. This parameter change in the hardware configuration achieves improved equipment operation stability with relatively simple additions, avoiding complex software or algorithmic solutions.

Inventive Principle:
Principle #35Parameter changes

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

The redundant sensor system effectively corrects errors caused by blocked holes, maintaining signal stability and equipment reliability by generating a combined sense signal with a normal waveform, even in the presence of blocked or partially blocked holes.

Implementation Method 1

at least one pair of first sensors provided on one side of the encoding belt, wherein the first sensors of each pair generate a first sense signal and a first redundant sense signal respectively based on light emitted from the other side of the encoding belt and passing through the plurality of holes

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP2889585B1Encoder and encoding method for slip ring
Publication Date: 2017.05.24 NUCTECH CO LTD
  • EP2889585B1 patent drawingFigure 1~2
  • EP2889585B1 patent drawingFigure 3~4
  • EP2889585B1 patent drawingFigure 5~6

AI summary

Disclosed is an encoder and encoding method for slip ring. The encoder includes: an encoding belt (50) that is fixed to a slip ring and has a plurality of holes regularly arranged on the encoding belt; at least one pair of first sensors (52-1, 52-2, 54-1, 54-2) provided on one side of the encoding belt, wherein the first sensors of each pair generate a first sense signal (A1, B1) and a first redundant sense signal (A2, B2) respectively based on light emitted from the other side of the encoding belt and passing through the plurality of holes, when the encoding belt rotates with the slip ring; and at least one signal combiner (56, 58) connected to the at least one pair of the first sensors, and configured to combine the first sense signal and the first redundant sense signal to obtain a combined sense signal (A', B') as a first encoded signal. With embodiments of the present invention, a redundant signal is provided by using a redundant sensor, and it is possible to avoid interference of foreign substance, improve stability of encoded signals and ensure normal operation of equipment.