Moving robot and controlling method thereof

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Solution Overview

Problem

Existing robot cleaners face challenges in preventing collisions with obstacles due to friction between the driving wheels and the floor, and sensor errors can also lead to collisions, affecting their ability to effectively navigate and clean areas, especially around corners.

Innovation Solution

The robot cleaner employs a controller that uses a combination of sensors, including ultrasonic and infrared sensors, to detect obstacles and adjust its path by reversing or changing direction to avoid collisions, while also considering the radius of rotation and braking distance, ensuring safe navigation and cleaning performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the robot cleaner uses obstacle sensors to detect and avoid obstacles, then collision prevention capability is improved, but sensor errors can still lead to collisions

Engineering Contradiction:
Improvecollision prevention capabilityVSAvoidsensor detection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary calculation process that uses the known radius of rotation as a reference parameter. The controller calculates the actual rotation radius during operation and uses this intermediate value to adjust the avoidance trajectory, serving as a mediator between sensor detection and final navigation decisions to compensate for sensor errors

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements feedback by continuously monitoring the actual rotation radius and using this information to adjust the avoidance path. The controller compares the calculated actual rotation radius with the predetermined radius and modifies the navigation parameters accordingly, creating a closed-loop control system that compensates for sensor inaccuracies

Inventive Principle:
Principle #23Feedback

2Reliability

If the robot cleaner performs avoidance operations around obstacles, then navigation safety is improved, but friction between driving wheels and floor affects braking distance and causes collisions

Engineering Contradiction:
Improvenavigation safetyVSAvoidfriction between driving wheels and floor
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent applies preliminary action by calculating and storing the actual rotation radius before the avoidance maneuver is executed. The controller uses this pre-calculated parameter to determine the appropriate braking distance and avoidance trajectory in advance, allowing the system to compensate for friction effects before the collision risk arises

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes parameters by adjusting the avoidance path parameters based on the calculated actual rotation radius. When friction conditions vary, the controller modifies the braking distance and trajectory parameters dynamically, transforming the fixed avoidance pattern into an adaptive one that accounts for changing friction conditions

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If the robot cleaner uses a fixed rotation radius for avoidance maneuvers, then control simplicity is improved, but actual rotation radius varies causing collision with obstacles

Engineering Contradiction:
Improvecontrol simplicityVSAvoidrotation radius accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by transitioning from a static, fixed rotation radius to a dynamic, adaptive rotation radius. The controller calculates the actual rotation radius during operation based on sensor data and adjusts the avoidance maneuver parameters in real-time, making the system adaptable to varying operational conditions while maintaining ease of control

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system replaces the mechanical assumption of a fixed rotation radius with a computational approach. Instead of relying on the physical constraint of a predetermined radius, the controller uses calculations based on sensor measurements and known parameters to determine the actual rotation radius, substituting mechanical rigidity with computational flexibility

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This solution effectively prevents collisions with obstacles, improves cleaning performance around corners, and maintains navigation accuracy even with varying friction conditions and sensor errors, enhancing the robot cleaner's operational reliability.

Implementation Method 1

a sensing unit to sense information related to an obstacle located in a moving direction of the robot cleaner

Methodology Applied
Scientific EffectUltrasonic wave reflection: Echo

Implementation Method 2

a sensing unit to sense information related to an obstacle located in a moving direction of the robot cleaner

Methodology Applied
Scientific EffectInfrared radiation detection: Infrared Radiation

Data Source

PatentEP3087894B2Moving robot and controlling method thereof
Publication Date: 2023.10.18 LG ELECTRONICS INC
  • EP3087894B2 patent drawingFigure 1A~1B
  • EP3087894B2 patent drawingFigure 1C
  • EP3087894B2 patent drawingFigure 1D~1E

AI summary

A robot cleaner (100) includes a main body, a driving unit (130) for moving the main body, a sensing unit (140) for sensing information related to an obstacle (300), and a controller (180) for controlling the driving unit (130) to prevent collision of the main body with the obstacle (300). In the robot cleaner (100), the controller (180) controls the driving unit (130) to reverse the main body with respect to the obstacle (300) so as to prevent the collision of the main body with the obstacle (300), based on a distance between the main body and the obstacle (300).