Nested Suction Cup Vacuum Sensing for Wall-Climbing Stability

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Solution Overview

Problem

Existing window-cleaning devices with single suction cups face gas leakage due to sliding friction, leading to insufficient vacuum pressure and potential device detachment from surfaces, especially when encountering gaps or bumps.

Innovation Solution

A suction apparatus with an inner and outer suction cup, connected to a vacuum detection unit featuring a deformable element and strain gauge, which controls the device to stop or redirect if vacuum pressure falls below a threshold, ensuring the inner suction cup is protected from further bumps and maintaining surface adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a single suction cup is used for window cleaning, then the device can be independently driven by a wheel or track, but gas leakage occurs due to sliding friction causing insufficient vacuum pressure and potential device detachment

Engineering Contradiction:
Improveindependent driving capabilityVSAvoidvacuum pressure stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The suction cup is divided into nested inner and outer suction cups, each capable of maintaining vacuum pressure independently. This segmentation allows the device to maintain reliable attachment even when one suction cup encounters gas leakage or surface irregularities, resolving the contradiction between independent driving capability and vacuum pressure stability.

Inventive Principle:
Principle #1Segmentation

2Speed

If the wheel rolls on the glass surface, then the device can move along vertical walls, but the portion between vacuum chamber and wall surface experiences sliding friction causing seal gas leakage

Engineering Contradiction:
Improvemovement speed along wallVSAvoidgas leakage from sliding friction
Core Design Contradiction:
SpeedVSObject-generated harmful factors

Solution Approach 1:

The suction system is segmented into nested inner and outer suction cups, each with its own vacuum chamber. This allows the device to move along the wall while distributing the sealing function across multiple independent units, reducing the impact of sliding friction-induced gas leakage on overall vacuum pressure stability.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If a single suction cup encounters gaps or bumps on the glass surface, then the device can adapt to surface irregularities, but gas leakage is easily caused leading to atmospheric pressure unbalance and device detachment

Engineering Contradiction:
Improveability to handle surface irregularitiesVSAvoidvacuum pressure maintenance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The suction system uses nested inner and outer suction cups that can independently adapt to surface irregularities. When one suction cup encounters gaps or bumps causing gas leakage, the other maintains vacuum pressure, ensuring continuous reliable attachment and preventing device detachment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The nested structure of inner and outer suction cups provides a backup system that cushions against the harmful effects of gas leakage. When one suction cup fails to maintain seal due to surface irregularities, the other suction cup is already in position to maintain vacuum pressure, preventing atmospheric pressure unbalance and device detachment.

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

4Measurement precision

If the outer suction cup fails and the outer negative pressure chamber is disabled, then the device can detect the failure through the vacuum detection unit, but the inner suction cup may be further damaged by additional bumps

Engineering Contradiction:
Improvevacuum pressure detection accuracyVSAvoidinner suction cup protection
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The vacuum detection unit continuously monitors the vacuum pressure in the outer negative pressure chamber and provides feedback to the control unit. When gas leakage is detected, the control unit responds by adjusting the running unit's operation, creating a feedback loop that protects the inner suction cup from further damage by preventing it from encountering additional surface irregularities.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The vacuum detection unit continuously monitors vacuum pressure before catastrophic failure occurs. When the outer suction cup shows signs of failure, the system takes preliminary protective action by adjusting the running unit's operation, preventing the inner suction cup from being subjected to further damaging surface irregularities.

Inventive Principle:
Principle #10Preliminary action

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

Prevents device detachment by maintaining sufficient vacuum pressure and allowing the glass-wiping device to navigate safely over small bumps and cracks, ensuring stable operation.

Implementation Method 1

the deformable element 20 being hermetically attached on an opening 141 on the top of the outer negative pressure chamber 14, the strain gauge 21 being arranged on the deformable element 20

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 2

the strain gauge 21 being arranged on the deformable element 20

Methodology Applied
Scientific EffectStrain gauge measurement: Piezoresistive Effect

Implementation Method 3

a cavity inside the inner suction cup 11 forms an inner negative pressure chamber 13 by vacuum-pumping, a cavity between the inner suction cup 11 and the outer suction cups 12 forms an outer negative pressure chamber 14 by vacuum-pumping

Methodology Applied
Scientific EffectVacuum suction: Suction

Data Source

PatentEP2835085B1Suction apparatus
Publication Date: 2018.06.06 ECOVACS ROBOTICS CO LTD
  • EP2835085B1 patent drawingFigure 1~2
  • EP2835085B1 patent drawingFigure 3

AI summary

A suction apparatus, a glass-wiping device and a run control method therefor. The suction apparatus comprises a suction cup unit (1). The suction cup unit (1) comprises an inner suction cup (11) and an outer suction cup (12). The inner suction cup (11) is arranged on the inside of the outer suction cup (12). A chamber on the inside of the inner suction cup (11) forms an inner negative pressure chamber (13) via vacuum suction. A chamber between the inner and outer suction cups (11 and 12) forms an outer negative pressure chamber (14) via vacuum suction. The outer negative pressure chamber (14) is connected to a vacuum detection unit. The vacuum detection unit comprises a distensible piece (20) and a distension-sensing piece (21). The distensible piece (20) is sealedly connected onto an opening on the top end of the outer negative pressure chamber (14). The distensible piece (20) has arranged thereon the distension-sensing piece (21). The glass-wiping device is provided with the suction apparatus, when in cases of failure of the outer suction cup (12) in the suction apparatus and of failure of the outer negative pressure chamber (14), the glass-wiping device will take measures immediately to prevent an increased number of small protrusions from entering the inner suction cup (11), thus preventing the phenomenon of the glass-wiping device falling off a wall from occurrence.