Robot Arm Distance Mapping for Human-Robot Safety Monitoring

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Solution Overview

Problem

In human-robot collaboration, especially in confined industrial spaces, existing methods fail to reliably and rapidly detect hazardous situations posed by robot tools to humans, lacking robustness against interference and quick response times.

Innovation Solution

A method utilizing a reference map with map sections storing positional information of surroundings, where a distance sensor attached to the robot arm performs repeated distance measurements, transforming measured positions into a stationary coordinate system to determine if objects are within a tolerance range, and if not, the robot is brought into a safe state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical safety devices such as fences or barriers are used to protect humans from robots, then human safety is improved, but the robot's operational effectiveness and space utilization deteriorate

Engineering Contradiction:
Improvehuman safetyVSAvoidrobot operational effectiveness
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces mechanical safety devices (fences, barriers) with an optical sensing system consisting of distance sensors and a reference map-based detection method. This substitution eliminates the need for physical enclosures while maintaining safety through continuous monitoring of the robot's surroundings and automatic intervention when unauthorized objects are detected.

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

Solution Approach 2:

The patent introduces a control unit as an intermediary between the distance sensors and the robot's motion control. This intermediary processes sensor data, compares it against the reference map, detects deviations indicating unauthorized objects, and triggers appropriate safety responses, thereby enabling safety without mechanical barriers.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the detection method is made robust against interference to ensure reliable hazard detection, then detection accuracy is improved, but response speed deteriorates

Engineering Contradiction:
Improvedetection accuracyVSAvoidresponse speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent performs preliminary actions by pre-storing accurate position information of the environment and authorized objects in a reference map during a setup phase. This pre-processing allows the system to quickly detect hazards during operation by simply comparing current sensor readings against the pre-established reference, enabling fast response without complex real-time analysis.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the environment into a grid-based reference map with discrete position information for different locations. This segmentation allows the system to efficiently search and compare only relevant map sections rather than processing the entire environment data, thereby maintaining both detection accuracy and fast response speed.

Inventive Principle:
Principle #1Segmentation

3Productivity

If the robot operates in confined spaces to improve space utilization, then productivity is improved, but the ability to mechanically isolate humans from robots deteriorates

Engineering Contradiction:
Improvespace utilizationVSAvoidmechanical isolation capability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent replaces mechanical isolation (physical separation barriers) with an electronic sensing and control system. Distance sensors continuously monitor the robot's surroundings, and the control unit processes this data to detect unauthorized objects in the robot's workspace, enabling safe operation in confined spaces without mechanical barriers.

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

Solution Approach 2:

The patent implements a feedback mechanism where distance sensors continuously provide information about objects in the robot's vicinity, the control unit processes this feedback by comparing it against the reference map, and the system responds by interrupting motion or alerting operators when unauthorized objects are detected, enabling safe confined-space operation.

Inventive Principle:
Principle #23Feedback

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

Enables rapid and robust detection of dangerous situations, ensuring human safety by quickly transitioning the robot to a safe state when a surrounding object is outside the defined tolerance range, thereby preventing potential hazards.

Implementation Method 1

at least one distance measurement for a measuring point of an environment object is carried out with a distance sensor attached to the movable machine part

Methodology Applied
Scientific EffectTime of Flight: Time of Flight

Data Source

PatentEP4108390B1Method for secure operation of a movable machine part
Publication Date: 2023.08.02 SICK AG
  • EP4108390B1 patent drawingFigure 1~2
  • EP4108390B1 patent drawingFigure 3~4
  • EP4108390B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for the safe operation of a movable machine part, in particular a robot arm, preferably within the framework of human-robot collaboration, wherein: - a reference map with one or more map sections is provided, the reference map relating to a fixed coordinate system and at least one map section containing position information of the environment of the movable machine part; - at least one distance measurement for a measuring point of an environment object is carried out with a distance sensor attached to the movable machine part, the distance measurement determining the distance of the movable machine part to the measuring point; - the position of the measuring point in the fixed coordinate system is determined based on the position of the movable machine part; - the map section corresponding to the measuring point is determined based on the position of the measuring point.If multiple map sections are available, - a comparison of the measuring point's position with the position information is performed to determine whether the surrounding object lies outside a tolerance range relative to the surrounding position information, - the moving machine part is brought into a safe state if the surrounding object lies outside the tolerance range.