Machine Safety System with Safe and Non-Safe Sensor Segmentation

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Solution Overview

Problem

Current safety systems in machine protection, particularly those using laser scanners, are limited in their ability to transfer high-quality sensor information externally due to safety standards, resulting in restricted flexibility and complexity in implementing advanced safety functions.

Innovation Solution

A safety system that combines safe and non-safe sensors, where safe sensors generate reliable data for error checking and plausibility, while non-safe sensors process complex evaluations, allowing for flexible and complex safety functions to be implemented without requiring high-performance safety interfaces or controls.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If safe sensors output only compressed binary switching signals to meet safety standards, then safety reliability is improved, but information content and flexibility for complex safety functions are lost

Engineering Contradiction:
Improvesafety reliabilityVSAvoidinformation content
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The system segments the data processing into two independent paths: a safe path that processes and outputs compressed binary switching signals for safety-critical functions, and a non-safe path that processes and outputs uncompressed sensor data for complex safety functions. This segmentation allows each path to operate according to its specific requirements without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a non-safe controller as an intermediary component that receives uncompressed sensor data from safe sensors, processes it for complex safety functions, and outputs results to the machine control system. This intermediary enables the transfer of high-quality sensor information while maintaining safety boundaries through the safe controller.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If high-performance safety interfaces and controls are used to process complex sensor data, then flexibility and complexity of safety functions are improved, but system cost and complexity increase

Engineering Contradiction:
Improveflexibility of safety functionsVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system divides control functions into a safe controller for safety-critical binary signal processing and a non-safe controller for complex sensor data processing. This segmentation allows complex safety functions to be implemented using standard non-safe controllers rather than requiring overdimensioned safety controllers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses uncompressed sensor data as a copy of the original sensor information for complex evaluations in the non-safe controller, while the safe controller continues to use compressed binary signals. This copying approach enables complex safety functions without requiring the safe controller to process large amounts of data directly.

Inventive Principle:
Principle #26Copying

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 the implementation of complex safety functions and flexible adaptations, reducing the need for overdimensioned security solutions, and allowing various security levels to be mapped according to application needs, thereby reducing costs.

Implementation Method 1

The light is reflected on objects in the monitoring area and evaluated in the laser scanner

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

the distance of the object from the laser scanner is also deduced from the time of flight using the speed of light

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 3

The angular position of the deflection unit is used to deduce the angular position of the object

Methodology Applied
Scientific EffectAngular position control:

Data Source

PatentEP3709106B1Securing of a machine
Publication Date: 2021.01.06 SICK AG
  • EP3709106B1 patent drawingFigure 1~2
  • EP3709106B1 patent drawingFigure 3~4
  • EP3709106B1 patent drawingFigure 5~6

AI summary

A safety system (10) for safeguarding a machine (12) is described, comprising at least one safe sensor (14, 14a-b) for generating safe data, wherein the safe sensor (14, 14a-b) also generates non-safe data and/or a non-safe sensor (16) is provided for generating non-safe data, wherein the safety system (10) further comprises a non-safe evaluation unit (18) for processing the non-safe data and a safe evaluation unit (20) configured to test the non-safe evaluation unit (18) by verifying an evaluation result of the processing of the non-safe data against the safe data. The safe data exhibits lower accuracy and/or is available less frequently compared to the evaluation result.