Ring Distance Sensor Layout for Closed Robot Protective Fields

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Solution Overview

Problem

Existing optoelectronic distance sensor systems for robots have gaps in their protective fields, which can lead to undetected objects, especially when stationary objects are approached in a straight line, and do not adequately adapt to the shape of the workpiece, posing safety risks in human-robot collaboration.

Innovation Solution

A sensor system with ring-shaped optoelectronic distance sensors arranged on a movable machine part, where sensors are rotatably mounted and angled to create a dynamic protective field that detects objects in gaps, ensuring detection by adjusting the number and positioning of sensors to form a quasi-closed protective shell, using time-of-flight technology and emitting invisible infrared light for enhanced safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a linear or flat arrangement of optoelectronic distance sensors is used, then the protective field can be implemented with simple sensor geometry, but gaps appear between protective fields when sensors are spaced apart, allowing objects to pass undetected

Engineering Contradiction:
Improvesensor arrangement simplicityVSAvoidprotective field continuity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies curvature by arranging sensors in a circular pattern around the robot arm rather than in a linear or flat configuration. This circular arrangement eliminates gaps between protective fields, creating a continuous 360-degree monitoring zone that prevents objects from passing undetected through spaces between sensors.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If the protective field is adapted to the tool shape, then protection is improved for the tool, but the workpiece shape is not considered, creating safety risks when the workpiece poses a risk

Engineering Contradiction:
Improveprotective field adaptation to toolVSAvoidworkpiece protection coverage
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements universality by designing a circular sensor arrangement that can simultaneously adapt to both tool shapes and workpiece shapes. The 360-degree circular configuration provides omnidirectional monitoring that covers both the tool area and workpiece area, allowing the same sensor system to protect against risks from both sources without requiring separate adaptation mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If multiple distance sensors are arranged in a ring with acute angles, then a denser protective field is created that detects objects in gaps, but the device complexity increases

Engineering Contradiction:
Improveobject detection capabilityVSAvoidsensor system configuration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the monitoring task among multiple individual distance sensors arranged in a ring, with each sensor responsible for monitoring a specific angular sector. This segmentation allows the system to achieve comprehensive 360-degree coverage with manageable individual sensor units, where each sensor contributes to the overall reliable detection while maintaining reasonable system complexity through modular configuration.

Inventive Principle:
Principle #1Segmentation

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 ensures reliable detection of objects in previously unprotected areas, minimizing risks by generating a denser, adaptive protective field that adjusts based on object size and movement, ensuring safety through intrinsic safety design and error detection mechanisms.

Implementation Method 1

the distance sensor is a time-of-flight sensor

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 2

emitting invisible infrared light

Methodology Applied
Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 3

picks up the light pulses reflected from an object in the measuring area

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3578867B1Sensor system with optoelectronic distance sensors
Publication Date: 2021.01.20 SICK AG
  • EP3578867B1 patent drawingFigure 1
  • EP3578867B1 patent drawingFigure 2
  • EP3578867B1 patent drawingFigure 2.1

AI summary

Sensor system (1) with optoelectronic distance sensors (2) for monitoring a danger zone (3) on a movable machine part (4) with at least one protective field (5), wherein the optoelectronic distance sensors (2) are arranged in a ring shape in a first ring (6) on the movable machine part (4), wherein a tool (4) is arranged on the movable machine part (4), wherein the optical axes (9) of the distance sensors (2) each have an acute angle (α) tangential to the ring shape or the distance sensors (2) are arranged rotatably on the ring (6).