Muting Sensor Layout for Accurate Entry Detection Disabling
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Solution Overview
Problem
Existing entry detection systems face challenges in disabling detection of objects allowed to enter a predefined region, particularly due to limited installation space and the need for accurate detection of object shapes.
Innovation Solution
The system includes an entry detection sensor and a muting sensor section with first and second units, each comprising pairs of sensors disposed on opposite sides of the entry detection plane. The control unit disables the entry detection sensor based on detection states from the muting sensor section, ensuring appropriate disabling of allowed objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two sets of retroreflective photoelectric sensors are installed as muting sensors with intersecting detection ranges, then the light curtain can be disabled when an article is detected, but the installation space becomes large and the distance between detection positions cannot be secured
Solution Approach 1:
The muting sensor section is divided into a first unit with a pair of first sensors and a second unit with a pair of second sensors. The first sensors detect objects approaching from one side of the entry detection plane, while the second sensors detect objects on the other side. This segmentation allows each sensor pair to operate independently with non-intersecting detection ranges, reducing the required installation space while maintaining reliable detection coverage.
Solution Approach 2:
Instead of using intersecting detection ranges in the same spatial dimension (which requires large installation space), the invention transitions to using sensors positioned on opposite sides of the entry detection plane, utilizing the third dimension (depth/distance from the plane) to achieve complete object detection without requiring large lateral installation space.
2Reliability
If the intersecting angle of detection ranges is increased to secure distance from the detection plane, then detection reliability improves, but the installation space becomes even larger
Solution Approach 1:
Instead of increasing the intersecting angle of sensors positioned in front of the detection plane (which would require even more installation space), the invention inverts the approach by positioning sensor pairs on both sides of the entry detection plane. This allows detection without requiring increased intersecting angles or additional installation space.
3Area of stationary object
If muting sensors are positioned close to the light curtain due to limited installation space, then installation space is saved, but the light curtain may not be appropriately disabled depending on the shape of the object
Solution Approach 1:
The first sensors are positioned to detect objects before they reach the entry detection plane, allowing the system to prepare for disabling the light curtain in advance. The second sensors continue detection after the object passes through the plane, ensuring the disabling state is maintained throughout the object's passage. This preliminary and continuous detection ensures reliable disabling regardless of object shape.
Data Source
AI summary
In an entry detection system, detection of an object that is allowed to enter the region is appropriately disabled. An entry detection system for detecting an object entering a region includes: an entry detection sensor configured to detect whether or not a part of the object is present within an entry detection plane; a muting sensor section including a first unit and a second unit; and a control unit. The control unit disables the entry detection sensor in response to at least one of a first detection state and a second detection state being established, the first detection state is a state in which the first unit provided on a passing direction-first side of the entry detection plane detects the object, and the second detection state is a state in which the second unit provided on a passing direction-second side of the entry detection plane detects the object.