Autonomous Cleaning Robot Brush Reversal for Self-Disentangling

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Solution Overview

Problem

Autonomous coverage robots face challenges in navigating and operating effectively in environments with obstacles, particularly when entangled by fabric, strings, or other soft media, as they require continuous human intervention to disentangle and resume operation.

Innovation Solution

The implementation of a robotic system with a differential drive mechanism, edge cleaning heads, and a controller using behavior-based robotics to manage sensor inputs, allowing the robot to autonomously detect and respond to entanglements by reversing the brush motor and using flexible flaps to unwind entangled cords or strings, thereby resuming operation without human intervention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If the robot operates autonomously in unstructured environments with obstacles, then the robot's ability to perform cleaning tasks independently is improved, but the robot frequently becomes entangled by fabric, strings, or other soft media requiring human intervention

Engineering Contradiction:
Improveautonomous operationVSAvoidcontinuous operation
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The robot is equipped with sensors and control systems that enable it to autonomously detect entanglements and execute disentanglement maneuvers without human assistance. The system monitors its own operational state and automatically responds to obstacles, allowing the robot to service itself during cleaning tasks.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The robot incorporates sensors that provide real-time feedback about entanglement conditions detected during operation. This feedback loop enables the control system to recognize when entanglement occurs and trigger appropriate disentanglement actions, improving the robot's ability to maintain continuous autonomous operation.

Inventive Principle:
Principle #23Feedback

2Reliability

If the robot reverses the brush motor to disentangle obstacles, then the robot's ability to free itself from entanglements is improved, but energy consumption increases

Engineering Contradiction:
Improvedisentanglement capabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The brush motor operates in periodic cycles, alternating between normal cleaning rotation and reverse rotation for disentanglement. The motor reverses only when entanglement is detected by sensors, rather than continuously running in reverse, thereby reducing overall energy consumption while maintaining effective disentanglement capability.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The robot applies reverse rotation to the brush motor only partially - specifically when and where entanglement is detected - rather than continuously. This partial action approach minimizes energy expenditure on disentanglement maneuvers while still achieving the necessary freedom from obstacles.

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If the robot uses flexible flaps to unwind entangled cords, then the robot's ability to resume operation is improved, but the complexity of the cleaning head subsystem increases

Engineering Contradiction:
Improveoperation resumptionVSAvoidcleaning head subsystem
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The cleaning head incorporates flexible flaps that can bend and move to facilitate the unwinding of entangled cords and strings. These flexible elements passively assist in disentanglement through their physical properties, enabling the robot to resume operation without complex mechanical mechanisms.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The flexible flaps act as intermediaries between the brush motor and the entangled obstacles. They provide a mechanical interface that facilitates the unwinding process, allowing the robot to disentangle obstacles with simpler motor control rather than requiring complex disentanglement mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 the robot to continue cleaning operations autonomously by effectively disentangling itself from obstacles, reducing energy consumption and preventing damage to the robot and surfaces, ensuring continuous functionality in unstructured environments.

Implementation Method 1

a first cleaning roller rotatably coupled to the cleaning assembly housing and a second cleaning roller rotatably coupled to the cleaning assembly housing and rotating in an opposite direction of the first cleaning roller

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

an air mover that creates a negative pressure zone to draw air and debris into the cleaning bin through the inlet opening

Methodology Applied
Scientific EffectSuction: Suction

Data Source

PatentEP2464269B1Autonomous coverage robots
Publication Date: 2016.06.01 IROBOT CORP
  • EP2464269B1 patent drawingFigure 1
  • EP2464269B1 patent drawingFigure 2
  • EP2464269B1 patent drawingFigure 3

AI summary

An autonomous coverage robot includes a body, a drive system disposed on the body, and a cleaning assembly disposed on the body and configured to engage a floor surface while the robot is maneuvered across the floor surface. The cleaning assembly includes a driven cleaning roller, a cleaning bin disposed on the body for receiving debris agitated by the cleaning roller, and an air mover. The cleaning bin includes a cleaning bin body having a cleaning bin entrance disposed adjacent to the cleaning roller and a roller scraper disposed on the cleaning bin body for engaging the cleaning roller. The cleaning bin body has a holding portion in pneumatic communication with the cleaning bin entrance, and the air mover is operable to move air into the cleaning bin entrance.