An autonomous mobile robot for cleaning with a first and a second roller

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Solution Overview

Problem

Robotic vacuums face challenges in maximizing cleaning effectiveness, preventing hair and debris entanglement, and maintaining performance while minimizing size and production costs, particularly in handling hair and string-like debris that can stall the device.

Innovation Solution

The implementation of a compressible, resilient roller with V-shaped chevrons and a four-bar linkage mechanism in the cleaning head, which includes a tubular member with curvilinear spokes and vanes to direct debris into the vacuum airway, preventing entanglement and ensuring continuous cleaning performance across different floor types.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single rotating brush is used for cleaning, then the device structure is simple, but cleaning effectiveness is reduced and hair entanglement occurs

Engineering Contradiction:
Improvecleaning effectivenessVSAvoidcleaning head structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cleaning head is divided into two separate rollers: a front roller and a rear roller. Each roller independently contacts the floor surface and contributes to debris collection. This segmentation allows each roller to be simpler in structure while collectively achieving superior cleaning effectiveness compared to a single complex brush system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of using a single brush that rotates in one direction, the invention uses two rollers that rotate in opposite directions. The front roller rotates in the direction of robot motion, while the rear roller rotates opposite to the motion direction. This inversion of rotation directions prevents hair entanglement and improves cleaning effectiveness.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If traditional cleaning brushes are used, then production cost is low, but hair and string-like debris cause entanglement and stalling

Engineering Contradiction:
Improvecontinuous cleaning performanceVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The rear roller rotates in the opposite direction to the front roller, creating a scissoring action that cuts and prevents hair entanglement. This opposite rotation mechanism reliably prevents continuous cleaning interruptions while remaining mechanically simple and cost-effective to manufacture.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention converts the problematic hair and string-like debris into a benefit by using the opposite rotation of the rear roller to cut and fragment these materials. What was previously a harmful entangling substance becomes material that is easily processed and collected without causing stalling.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Power

If the robotic vacuum is designed for compact size, then production cost and storage are reduced, but cleaning power is insufficient

Engineering Contradiction:
Improvecleaning powerVSAvoidoverall device size
Core Design Contradiction:
PowerVSVolume of moving object

Solution Approach 1:

The cleaning function is segmented into two rollers positioned at the front and rear of the cleaning head. This segmentation allows each roller to be compact in size while collectively providing sufficient cleaning power. The distributed arrangement maximizes the cleaning width within a compact overall footprint.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention extends the cleaning capability in the longitudinal dimension by placing rollers at both the front and rear of the cleaning head, rather than relying on a single large brush. This dimensional arrangement increases effective cleaning power while maintaining a compact transverse profile.

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

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 solution enhances debris collection efficiency, reduces noise, and maintains airflow velocity by preventing hair and string-like debris from wrapping around the roller, allowing the robotic vacuum to operate effectively on various surfaces without stalling.

Implementation Method 1

The engagement elements enable the transfer of torque from the drive shaft to the resilient tubular member via the resilient curvilinear spokes.

Methodology Applied
Scientific EffectTorque transfer: Torque

Implementation Method 2

the resilient compressible material may be affixed permanently to the rigid shaft to resist shear forces that would otherwise dislodge the resilient compressible material.

Methodology Applied
Scientific EffectShear force resistance: Shear Stress

Implementation Method 3

a tubular member with curvilinear spokes and vanes to direct debris into the vacuum airway, preventing entanglement

Methodology Applied
Scientific EffectDebris direction:

Implementation Method 4

The implementation of a compressible, resilient roller with V-shaped chevrons and a four-bar linkage mechanism in the cleaning head

Methodology Applied
Scientific EffectMechanical linkage: Four-Bar Linkage

Implementation Method 5

impellers can be located in a robotic vacuum dust bin to pull air carrying swept dirt, hair, and debris into the dust bin

Methodology Applied
Scientific EffectAir movement: Impeller

Implementation Method 6

a vacuum stream that pulls the debris into the cleaning head and generally toward the dust bin

Methodology Applied
Scientific EffectSuction: Suction

Data Source

PatentEP3028617B1An autonomous mobile robot for cleaning with a first and a second roller
Publication Date: 2021.01.06 IROBOT CORP
  • EP3028617B1 patent drawingFigure 1
  • EP3028617B1 patent drawingFigure 2A~2B
  • EP3028617B1 patent drawingFigure 3

AI summary

An autonomous coverage robot comprising: a chassis; a drive system mounted to the chassis and configured to maneuver the robot over a cleaning surface; and a cleaning assembly mounted on the chassis, the cleaning assembly comprising: a roller housing (380); a first roller (110, 310) rotatably mounted to the roller housing (380) and defining a first longitudinal axis and being rotatable about the first longitudinal axis in a first direction; a second roller (120, 320) rotatably mounted to the roller housing (380) rearward of and substantially parallel to the first roller (110, 310), the second roller (120, 320) defining a second longitudinal axis and being rotatable about the second longitudinal axis in a second direction opposite of the first direction; wherein the second roller (120, 320) is spaced from the first roller (110, 310) to form an air gap therebetween; and wherein the first and the second rollers (110, 120, 310, 320) are each resiliently compressible to allow passage of an object having a dimension larger than the air gap between the first and second rollers (110, 120, 310, 320).