Off-Axis IR Reflection Sensing for Glass Wall Detection in Robots

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Solution Overview

Problem

Existing sensors, such as ultrasound, laser range finders, LIDARs, and microwaves, struggle to accurately detect glass walls and doors due to their transparency and inability to provide precise edge detection, leading to potential collisions in autonomous systems like robots.

Innovation Solution

Deployment of an IR imaging device and an IR emitter that emits a thermal signature outside the field-of-view, which is reflected on glass surfaces, allowing the system to determine distance and angle through triangulation, effectively identifying glass walls and doors using long-wavelength IR technology.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional sensors (ultrasound, laser, LIDAR, microwave) are used to detect obstacles, then the system can detect most objects, but glass walls and doors cannot be detected accurately due to transparency

Engineering Contradiction:
Improvedetection accuracyVSAvoidability to detect transparent objects
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the detection parameter from visible light/laser/microwave frequencies to infrared thermal signature frequencies. Glass is transparent to traditional sensors but reflects infrared thermal radiation, allowing the IR imaging device to detect glass surfaces by capturing reflected thermal signatures from the IR emitter.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces an infrared thermal signature as an intermediary between the robot and the glass obstacle. The IR emitter projects a thermal pattern that reflects off the glass surface, and the IR imaging device captures this reflected pattern, creating an indirect detection mechanism that overcomes glass transparency to traditional sensors.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If touch sensors or collision buttons are installed on the robot, then collision detection is possible, but collisions cannot be prevented as detection only occurs after contact

Engineering Contradiction:
Improvecollision detection capabilityVSAvoidresponse time before collision
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary detection by actively projecting an infrared thermal signature and capturing its reflection before any physical contact occurs. The system calculates distance and angle from the reflected pattern, enabling the robot to identify glass obstacles in advance and adjust its navigation path to prevent collisions entirely.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If high-precision detection systems are implemented, then detection accuracy improves, but system cost and complexity increase significantly

Engineering Contradiction:
Improvedistance and angle measurement accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs relatively inexpensive infrared components (IR emitter and IR imaging device) compared to high-precision LIDAR or laser-based systems. The approach uses passive thermal radiation detection rather than active high-power laser ranging, reducing both hardware cost and system complexity while achieving sufficient precision for navigation and collision avoidance.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 method provides a cost-effective solution for accurate detection of glass surfaces, enabling autonomous systems to navigate safely by determining the presence, distance, and angle of glass walls and doors, even when transparent, thereby preventing collisions.

Implementation Method 1

emitting, by an IR thermal emitter, an IR thermal signature from the autonomous system

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 2

detecting presence of the IR thermal signature that reflects on the reflective surface

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4455718A1Glass walls and doors detection and distance measuring for robots and method of controlling the same
Publication Date: 2024.10.30 MIKE IP HOLDINGS PTE LTD
  • EP4455718A1 patent drawingFigure 1
  • EP4455718A1 patent drawingFigure 2A~2B
  • EP4455718A1 patent drawingFigure 3~4C

AI summary

A method for detecting glass wall with reflective surface for an autonomous system. The method comprises deploying at least one IR imaging device and at least one IR emitter on the autonomous system, wherein the IR imaging device comprises a field-of-view (FOV); emitting, by an IR thermal emitter, an IR thermal signature from the autonomous system, wherein the IR thermal signature is located outside of the FOV; detecting presence of the IR thermal signature that reflects on the reflective surface; and determining a distance and angle of the autonomous system from the reflective surface based on the refected IR thermal signature within the FOV. The reflective surface will be identify as the glass wall. A sensor assembly and an autonomous system is also provided.