Myoelectric Sensor with Bent Connecting Cables for Limb Movement

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Solution Overview

Problem

Conventional sheet-like myoelectric sensors have a narrow detection range, making it difficult to obtain sufficient electromyogram information, and are prone to disconnection due to limb deformation and attachment/detachment operations.

Innovation Solution

An elastically expandable and contractible annular myoelectric sensor with multiple detection units arranged circumferentially, connected by cables with bent portions that adjust to changes in distance, ensuring continuous electrical connection and maintaining contact with the limb surface during deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the detection range of the myoelectric signal is widened by arranging multiple detection units around the limb, then the electromyogram information obtained is sufficient, but the distance between adjacent detection units changes during body movement causing excessive partial deformation and disconnection of wiring

Engineering Contradiction:
Improvedetection rangeVSAvoidwiring connection
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The connecting cable is designed with a bent portion that can dynamically change its shape in response to distance changes between detection units. The bent portion allows the cable to adapt its configuration as the wearing band expands or contracts during body movement, maintaining electrical connection while accommodating dimensional changes.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The cable's physical state changes through parameter modification - specifically, the bent portion changes its curvature and configuration based on the distance between detection units. This parameter change enables the cable to maintain optimal electrical connection across varying distances without excessive deformation or disconnection.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the myoelectric sensor is designed as a sheet shape for easy attachment, then the ease of operation is improved, but the detection range remains narrow and insufficient electromyogram information is obtained

Engineering Contradiction:
Improveease of attachmentVSAvoiddetection range
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The sensor is segmented into multiple detection units arranged circumferentially around the limb, with each unit containing detection electrodes. This segmentation allows the sensor to maintain ease of attachment as a single wearing band while expanding the detection range through multiple measurement points distributed around the limb.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The detection approach transitions from a two-dimensional sheet configuration to a three-dimensional circumferential arrangement around the limb. By distributing detection units in the circumferential dimension, the sensor achieves wide detection range while maintaining the simplicity of a single wearable component.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If the wearing band is made elastically expandable and contractible to follow limb deformation, then the adaptability to body movement is improved, but the connecting cable experiences excessive partial deformation and may disconnect

Engineering Contradiction:
Improveadaptability to limb deformationVSAvoidelectrical connection
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The connecting cable incorporates a bent portion that dynamically adjusts its shape and configuration in response to the expandable and contractible movements of the wearing band. This dynamic adaptation allows the cable to maintain electrical connection while the wearing band follows limb deformation through elastic expansion and contraction.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The bent portion in the connecting cable is designed beforehand to accommodate and cushion the deformation forces generated during wearing band expansion and contraction. This pre-designed flexibility prevents excessive partial deformation and disconnection while allowing the wearing band to adapt to limb movements.

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

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

Enables wide-range detection and reliable output of myoelectric signals despite limb movement or sensor attachment/detachment, preventing excessive deformation and ensuring consistent electrical connection.

Implementation Method 1

Each connecting cable has at least one bent portion whose bent shape changes in accordance with a change in distance between the myoelectric detection units adjacent to each other

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3260044B1Myoelectric sensor
Publication Date: 2022.10.05 HARADA ELECTRONICS CO LTD
  • EP3260044B1 patent drawingFigure 1
  • EP3260044B1 patent drawingFigure 2
  • EP3260044B1 patent drawingFigure 3

AI summary

[Problem] To enable the detection of a wide range of myoelectric signals of limbs using a plurality of myoelectric detection units, and to enable those myoelectric signals to be reliably output regardless of changes in the shape of the limbs due to body movement or the attachment/removal of the myoelectric detection units. [Solution] Provided is a myoelectric sensor for detecting myoelectric signals which accompany body movement, wherein the myoelectric sensor comprises: a wearing band (1) that is elastic, expandable, and circular, and that is worn around a limb to surround the limb tightly; myoelectric detection units (3) a plurality of which are disposed in the circumferential direction on the wearing band with intervals there between so as to cause each of a plurality of myoelectric detection electrodes (2) to be in close contact with the surface of the limb, and which detect myoelectric signals from corresponding positions on the limb using the myoelectric detection electrodes; and connection cables (4) that electrically connect mutually adjacent myoelectric detection units and thereby transmit the myoelectric signals. The connection cables each include a bent portion (4a), the bent shape of which changes in response to changes in the distance between the mutually adjacent myoelectric detection unit.