Optoelectronic Access Protection with Contour-Based Object Authorization
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Solution Overview
Problem
Existing access protection systems in manufacturing environments face challenges in distinguishing between authorized and unauthorized objects, leading to unnecessary interruptions in machine or robot operations, and are prone to errors, manipulation, and high installation and maintenance costs, especially in environments with metal objects or reinforced floors.
Innovation Solution
An access protection system utilizing a combination of first and second optoelectronic sensors, where the second sensor divides the area into adjacent contour detection fields, and an evaluation unit compares detected object contours with predefined references to suppress the safety function only for permissible objects, ensuring reliable differentiation between impermissible and permissible objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If induction loops are used to bypass the safety function for authorized objects, then the throughput interruption is reduced, but the installation and maintenance cost increases significantly
Solution Approach 1:
The patent replaces the mechanical/electrical induction loop system with an optoelectronic sensor system that uses light-based detection. The sensor detects objects without requiring physical contact or specialized infrastructure like induction loops embedded in the floor, thereby eliminating the high installation and maintenance costs while maintaining the ability to distinguish authorized objects and prevent unnecessary throughput interruptions.
2Adaptability or versatility
If induction loops are used to bypass the safety function, then authorized object access is improved, but the system becomes susceptible to manipulation and interference
Solution Approach 1:
The patent replaces the electromagnetic induction loop system with an optoelectronic detection system that uses light barriers and sensors. This substitution eliminates the interference issues between different induction loops and the susceptibility to electromagnetic manipulation, while maintaining the ability to recognize authorized objects through optical detection methods that are harder to manipulate or interfere with.
3Adaptability or versatility
If induction loops are used in steel-reinforced floors, then authorized object detection is possible, but the detection reliability decreases
Solution Approach 1:
The patent replaces the induction loop system that relies on electromagnetic induction through the floor structure with an optoelectronic sensor system that detects objects using light. This substitution eliminates the problem of steel reinforcement interfering with the detection signal, as optical sensors can detect objects through air space without being affected by the electrical conductivity or magnetic properties of steel-reinforced floors.
4Productivity
If the safety function is bypassed using induction loops, then authorized workflows are enabled, but false bypasses occur leading to process standstills
Solution Approach 1:
The patent replaces the induction loop system with an optoelectronic sensor system that provides more reliable object detection and classification. The optical detection method reduces false positives and false negatives in identifying authorized objects, thereby minimizing false bypasses that would otherwise cause unnecessary process standstills while still enabling legitimate authorized workflows to proceed without interruption.
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
This solution allows for automatic deactivation of the safety function during permissible workflows, reducing unnecessary interruptions and enhancing reliability, while maintaining safety by accurately identifying authorized objects and preventing unauthorized access.
Implementation Method 1
at least one second optoelectronic sensor, which is set up for the location-resolving monitoring of an area in front of the monitoring area
Implementation Method 2
at least one first optoelectronic sensor, which is set up to detect an intrusion of an object into the monitoring area
Data Source
Figure 1~2
Figure 3a~3b
Figure 3c
AI summary
The present invention relates to an access control system for monitoring the access of objects to a monitored area and comprises: - at least one first optoelectronic sensor configured to detect the ingress of an object into the monitored area, - at least one second optoelectronic sensor configured for spatially resolved monitoring of a pre-surface area upstream of the monitored area, - and an evaluation unit which communicates with the first and the second sensors, wherein the evaluation unit is configured to trigger a safety function when an object enters the monitored area and is configured to suppress the safety function when the intruding object is classified as an authorized object. It is proposed that the pre-surface area consists of several adjacent contour detection fields of the second sensor.Furthermore, the evaluation unit is configured to detect the contour of an object penetrating the foreground, based on signals received from the second sensor, within a contour detection field. The detected contour is then compared with a predefined reference contour, and the determined position of the detected contour is compared with a reference position of the reference contour within the respective contour detection field. The reference contour is defined as a break in the contour detection field across its entire width at the reference position. The evaluation unit is further configured to classify the penetrating object as a permissible object only if the detected contour corresponds to the reference contour at the reference position.