Event-Based Image Sensor Self-Testing for Machine Safeguarding
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Solution Overview
Problem
Existing safety technologies for industrial machines, particularly in human-robot collaboration, lack reliable methods for detecting errors in event-based image sensors, which are crucial for ensuring safety and preventing accidents.
Innovation Solution
An event-based optoelectronic sensor system that includes a control and evaluation unit capable of performing self-tests on the image sensor, generating targeted optical stimuli to detect errors, and providing a safe output for initiating safety measures when hazards are detected or sensor failures occur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If event-based image sensors are used for safety monitoring in human-robot collaboration, then response time and dynamic range are improved, but reliability is worsened due to lack of error detection capability
Solution Approach 1:
The patent implements preliminary error detection by integrating verification circuits directly into the image sensor that continuously monitor pixel functionality. Test patterns are pre-programmed into the sensor memory, and the verification circuits automatically compare actual pixel outputs against expected patterns before safety decisions are made, enabling proactive detection of sensor failures.
Solution Approach 2:
The patent introduces verification circuits as an intermediary layer between the pixel array and the safety evaluation system. These circuits act as mediators that independently verify pixel functionality by comparing actual outputs against pre-stored test patterns, filtering out erroneous signals before they reach the safety control logic.
2Reliability
If dual-channel redundant design is implemented to improve safety reliability, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the safety verification function directly into the single-channel image sensor by integrating verification circuits and test pattern memory within the sensor itself. This consolidation eliminates the need for separate dual-channel redundancy systems while maintaining equivalent safety reliability through internal self-verification mechanisms.
Solution Approach 2:
The patent enables the image sensor to perform self-verification through integrated verification circuits that continuously monitor pixel functionality against pre-stored test patterns. The sensor serves its own safety verification needs internally, eliminating the need for external redundant systems or complex external monitoring infrastructure.
3Reliability
If functional monitoring is added to detect image sensor errors, then reliability is improved, but computing power and energy consumption increase
Solution Approach 1:
The patent replaces complex computational error detection methods with simple hardware-based verification circuits integrated into the sensor. Instead of using software algorithms that require significant computing power, the verification circuits perform direct hardware comparison of pixel outputs against pre-stored test patterns, dramatically reducing energy consumption while maintaining detection reliability.
Solution Approach 2:
The patent uses simple, low-cost verification circuits with pre-stored test patterns that can be quickly refreshed or replaced. The test pattern memory contains straightforward binary patterns that require minimal storage capacity and can be rapidly rewritten, enabling frequent verification cycles with minimal energy investment.
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 reliable and efficient monitoring of machines with high dynamic range and fast response times, reducing computing power and energy consumption while ensuring safety through near real-time detection and response, even in highly dynamic collaboration scenarios.
Implementation Method 1
Each pixel element checks whether it detects a change in intensity. Only in this case does it provide image information, in particular event-based image information.
Data Source
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AI summary
A safe optoelectronic sensor (10) for safeguarding a machine (24) is described, comprising an image sensor (14) with a plurality of pixel elements for generating image data and a control and evaluation unit (18) for evaluating the image data and for performing a functional test of the image sensor (14), in which the pixel elements are excited by a stimulus and the response of the pixel elements is compared with an expectation. The image sensor (14) is an event-based image sensor.