Robot navigational sensor system

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Solution Overview

Problem

Autonomous robotic vacuum cleaners face challenges in accurately detecting small, dark-colored obstacles such as chair legs, which can lead to collisions and damage, as existing detection methods are not effective in resolving the position of these objects with sufficient precision.

Innovation Solution

A proximity sensor system featuring a receiver and two emitters with twice-reshaped emission beams, angled to intersect the receiver's field of view, allowing for a bounded detection volume that can detect small, dark-colored objects with greater accuracy by sequentially activating the emitters and using baffling to control the beam shape and size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional sensor systems are used to detect obstacles, then the robot can detect general obstacles, but it cannot accurately detect small, dark-colored obstacles such as chair legs

Engineering Contradiction:
Improveobstacle detection precisionVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor system is segmented into multiple emitters and a receiver, with each emitter producing a specifically shaped beam. The detection space is divided into multiple zones with different detection capabilities, allowing precise detection of small, dark obstacles in specific regions while maintaining overall system simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the detection volume have different detection qualities. The twice-reshaped emission beams create concentrated detection zones with high precision for small, dark obstacles, while other regions provide broader coverage. This local optimization of detection quality resolves the contradiction between precision and complexity.

Inventive Principle:
Principle #3Local quality

2Productivity

If the robot travels at high speed to improve cleaning efficiency, then productivity increases, but the risk of collision with undetected obstacles increases

Engineering Contradiction:
Improvecleaning efficiencyVSAvoidcollision avoidance reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The sensor system performs preliminary detection of obstacles before the robot reaches them. The twice-reshaped emission beams are designed to detect small, dark obstacles at a distance, allowing the robot to identify and avoid obstacles before they become a collision risk, thus enabling high-speed operation with maintained safety.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If the robot slows down to improve obstacle detection accuracy, then measurement precision improves, but productivity decreases

Engineering Contradiction:
Improveobstacle detection precisionVSAvoidcleaning efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system replaces mechanical slowing down with an optical detection solution. The twice-reshaped emission beams and receiver configuration provide high-precision detection of small, dark obstacles without requiring the robot to reduce speed, thus maintaining both detection precision and productivity simultaneously.

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

4Area of stationary object

If diffuse emitter output is used to increase detection coverage, then the field of view expands, but the ability to detect small objects at specific distances decreases

Engineering Contradiction:
Improvedetection coverage areaVSAvoidobject position resolution
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The emission beam parameters are changed through the twice-reshaping process. The first shaping creates a focused beam, and the second shaping adjusts the beam characteristics to create an optimized detection pattern. This parameter optimization allows the system to maintain adequate coverage while achieving precise detection of small objects at specific distances.

Inventive Principle:
Principle #35Parameter changes

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 enables the robot to detect dark-colored and small obstacles at a predictable distance, allowing it to slow down and avoid collisions, improving navigation and reducing the risk of damaging sensitive objects.

Implementation Method 1

the receiver is arranged to detect radiation reflected from objects

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

an emitter which emits a signal having a field of emission and a photon detector having a field of view

Methodology Applied
Scientific EffectElectromagnetic radiation: Light

Data Source

PatentEP3317792B1Robot navigational sensor system
Publication Date: 2020.01.08 IROBOT CORP
  • EP3317792B1 patent drawingFigure 1A
  • EP3317792B1 patent drawingFigure 1B
  • EP3317792B1 patent drawingFigure 1C

AI summary

An autonomous robot comprises a robot body, a drive configured to propel the robot, a sensor system disposed on the robot body, and a navigation controller circuit in communication with the drive and the sensor system. The sensor system comprises at least one proximity sensor comprising a sensor body, and a first emitter, a second emitter and a receiver housed by the sensor body, wherein the receiver detects objects in a bounded detection volume of the receiver field of view aimed outward and downward beyond a periphery of the robot body. The receiver is disposed above and between the first and second emitters, the emitters having a twice-reshaped emission beams angled upward to intersect the receiver field of view at a fixed range of distances from the periphery of the robot body to define the bounded detection volume.