Cleaning Robot Side Brush Self-Cleaning via Whipping Motion

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Solution Overview

Problem

Dirt, especially damp or greasy dirt, tends to accumulate on the brush arm of a cleaning robot's side brush, impeding its rotation and cleaning efficiency.

Innovation Solution

The side brush's brush arm is designed to perform a whipping motion through controlled, jerky acceleration and deceleration, utilizing its flexural elasticity and resonant frequency, and is aided by centrifugal elements to fling off adhering dirt, which is then collected by a suction nozzle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the side brush rotates continuously to clean the floor surface, then cleaning action is maintained, but dirt accumulates on the brush arm and impedes rotation

Engineering Contradiction:
Improvecleaning actionVSAvoidrotation freedom
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The side brush alternates between continuous rotation for cleaning and periodic whipping motions for self-cleaning. The control unit activates the drive unit to generate whipping motions at predetermined intervals based on cleaning duration or distance traveled, allowing the brush to maintain cleaning effectiveness while periodically removing accumulated dirt that would otherwise impede rotation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The side brush performs self-cleaning through its own rotational movement and flexural properties. By utilizing the brush arm's natural elasticity and resonance characteristics, the system generates whipping motions that automatically fling off accumulated dirt without requiring external cleaning mechanisms or manual intervention.

Inventive Principle:
Principle #25Self-service

2Strength

If the brush arm is rigid to maintain structural strength, then durability is improved, but whipping motion cannot be achieved to remove dirt

Engineering Contradiction:
Improvestructural strengthVSAvoidwhipping motion capability
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The brush arm is designed with non-uniform flexibility along its length. The radially inner section maintains higher rigidity for structural support and connection to the hub, while the radially outer section has increased flexibility to enable whipping motion. This gradient in mechanical properties allows the brush arm to simultaneously withstand structural loads and perform self-cleaning through elastic deformation.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The brush arm transitions from a static rigid structure to a dynamic flexible element that can undergo large angular displacements during whipping motions. The controlled acceleration and deceleration of the side brush creates dynamic loads that exploit the brush arm's elastic properties, allowing it to whip outward and fling off dirt while maintaining structural integrity through its material and geometric design.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If gentle acceleration and deceleration is used to start and stop the side brush, then smooth operation is achieved, but dirt cannot be flung off the brush arm

Engineering Contradiction:
Improvesmooth operationVSAvoiddirt removal efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The control unit implements a dual-mode operation where gentle acceleration and deceleration are used during normal cleaning to maintain smooth operation, but periodic jerky acceleration and deceleration are applied to generate whipping motions for dirt removal. This alternating pattern allows the system to maintain operational smoothness while periodically achieving the high accelerations needed to fling off adhering dirt.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The jerky acceleration and deceleration creates mechanical vibrations and oscillations in the brush arm that amplify the whipping motion. By applying sudden changes in rotational speed, the system excites the brush arm's natural frequency, causing it to whip outward with increased amplitude and effectively fling off accumulated dirt that gentle operation cannot remove.

Inventive Principle:
Principle #18Mechanical vibration

4Ease of operation

If the radially outer section of the brush arm is made flexible to enable whipping motion, then dirt can be flung off, but structural strength may be compromised

Engineering Contradiction:
Improvewhipping motion capabilityVSAvoidstructural strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The brush arm employs a gradient structure where the radially inner section has higher material density and cross-sectional area for structural strength, while the radially outer section has reduced density and cross-sectional area for flexibility. This local differentiation allows the inner portion to bear structural loads and the outer portion to undergo large elastic deformations during whipping motions without compromising overall structural integrity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The brush arm is constructed from composite materials or a composite structure combining materials with different mechanical properties. The inner section uses stiffer, stronger materials to provide structural support, while the outer section uses more flexible, elastic materials that can withstand repeated whipping motions. This composite construction optimizes both strength and flexibility in different regions of the same component.

Inventive Principle:
Principle #40Composite materials

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

Effectively removes adhering dirt without significantly interrupting the cleaning process, enhancing the cleaning efficiency and effectiveness of the cleaning robot.

Implementation Method 1

At least one radially outer section of the brush arm is designed to be flexible. It is proposed to accelerate the brush arm during its rotational movement about the axis of rotation in such a way that it performs a whipping motion to fling off dirt that has accumulated on the brush arm.

Methodology Applied
Scientific EffectFlexural elasticity: Elasticity

Implementation Method 2

The side brush or brush arm can be driven by a drive unit, in particular an electric motor. Typically, the drive unit is controlled to gently accelerate the side brush when starting or to gently decelerate or coast to a stop when stopping. The proposed controlled, jerky acceleration or deceleration of the brush arm can set the radially outer section into oscillation, causing it to perform a whipping motion that flings dirt off.

Methodology Applied
Scientific EffectResonant frequency: Resonance

Implementation Method 3

The cleaning robot includes a side brush that rotates around a vertical axis. The side brush has at least one brush arm that, by rotating, moves across the floor surface to collect loose dirt.

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP4670603A1Cleaning robot with side brush
Publication Date: 2025.12.31 BSH HAUSGERATE GMBH
  • EP4670603A1 patent drawingFigure 1
  • EP4670603A1 patent drawingFigure 2
  • EP4670603A1 patent drawingFigure 3a~3d

AI summary

A cleaning robot (100) for cleaning a floor surface comprises a side brush (130) rotatable about a rotational axis (135) extending in a vertical direction. The side brush (130) has at least one radially projecting brush arm (145), wherein a radially outer section (155) of the brush arm (145) is flexible. A method (600) for cleaning a side brush (130) of such a cleaning robot (100) comprises the steps of determining (605) a cleaning requirement of the side brush (130); and of abruptly accelerating or decelerating (610, 615) the brush arm (145) about the rotational axis (135).