Robot Cleaner Multi-Sensor Lift Detection for User Safety

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Solution Overview

Problem

Existing robot cleaners struggle to accurately detect when they are lifted from the floor surface, leading to potential user injuries and erroneous operation during cleaning.

Innovation Solution

A robot cleaner equipped with a sensor system that includes tilt sensors, distance sensors, and light amount sensors, which work together with a controller to calculate lift information and control the power module accordingly, ensuring safe operation by stopping the cleaning process when lifted.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spring-connected wheel structure is used to detect lifting, then the robot can detect whether it is lifted, but the structure cannot be applied to robot cleaners that drive by mop rotation without separate wheels

Engineering Contradiction:

Improvelifting detection capabilityVSAvoidapplicability to mop-driven robot cleaners

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical spring-connected wheel detection system with an optical sensing system. The distance sensor (optical device) detects the distance between the robot cleaner and the floor surface, eliminating the need for mechanical wheels and springs. This substitution enables the lifting detection function to be applied to robot cleaners that drive solely by mop rotation without separate wheel structures.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a cliff sensor is used to detect distance from the floor surface, then the robot can determine whether it is lifted, but shaking during start/stop or foreign matter between mop and floor causes erroneous detection

Engineering Contradiction:

Improvedistance detection accuracyVSAvoidaccuracy of lifting determination

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent introduces dynamic judgment criteria that consider the robot cleaner's operational state. The controller determines whether the robot is lifting based on the relationship between the detected distance and the rotational state of the mop. When the mop is rotating, the controller accounts for normal shaking and only determines lifting when the distance exceeds a threshold for a predetermined time, thereby distinguishing between temporary shaking and actual lifting.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system continuously monitors the distance between the robot cleaner and the floor surface using the distance sensor, and the controller processes this feedback information in real-time. By comparing the distance measurements with rotational state information and applying time-based thresholds, the system provides accurate lifting determination that adapts to changing operational conditions, preventing erroneous detection during normal cleaning operations.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If the robot cleaner is driven by mop rotation without separate wheels, then driving and cleaning are unified, but detecting whether the robot is lifted by wheel structures is limited

Engineering Contradiction:

Improveunified driving and cleaning operationVSAvoiddifficulty of detecting lifting state

Core Design Contradiction:

Adaptability or versatilityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces mechanical detection methods with optical sensing. The distance sensor optically measures the distance between the robot cleaner and the floor surface, eliminating the need for mechanical wheel structures. This enables unified driving and cleaning operation through mop rotation while maintaining accurate lifting detection capability.

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

The system significantly improves the accuracy of detecting when the robot cleaner is lifted, reducing the risk of user injury and preventing erroneous operation, while also allowing the robot to adapt to various lifting scenarios.

Implementation Method 1

the sensor part may include a tilt sensor module configured to detect tilt information of the body part

Methodology Applied

Scientific EffectTilt detection: Accelerometer

Implementation Method 2

a distance sensor module configured to detect distance information from a floor surface on which the body part drives

Methodology Applied

Scientific EffectDistance measurement: Time of Flight

Implementation Method 3

a light amount sensor module configured to detect light amount information reflected from the floor surface

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS12279732B2Robot cleaner and control method thereof

Publication Date: 2025.04.22 LG ELECTRONICS INC

AI summary

A robot cleaner and a control method thereof are disclosed. A robot cleaner, according to an embodiment of the present invention, comprises: a tilt sensor module; a distance sensor module; and a light amount sensor module. Each piece of sensed information is transmitted to a lifting information calculation module. The lifting information calculation module calculates information on whether the robot cleaner is lifted, by using each piece of the transmitted information. If it is calculated that the robot cleaner is lifted off a floor, a power module is stopped. In addition, if it is calculated that the robot cleaner is not lifted off the floor, the power module is driven. Accordingly, when a user lifts the robot cleaner, injuries to the user caused by operation of a drive module can be prevented.