3D Sensor Assembly for Automatic Machine Restart After Safety Stops
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Solution Overview
Problem
Existing safety systems for industrial machines require manual intervention for restarting after a safety-related shutdown, which reduces productivity due to the need for human verification of clear danger zones, as current automatic restart solutions are inadequate.
Innovation Solution
A sensor arrangement using a 3D camera with a control and evaluation unit that stores 3D images before shutdown, identifies moving objects by comparing them to a reference map, and automatically restarts the machine when no one is detected within the danger zone, incorporating features like micro-movement detection and redundant sensors for enhanced reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual verification is performed before machine restart, then safety is ensured, but productivity decreases due to human intervention time
Solution Approach 1:
The system performs self-verification by automatically monitoring the danger zone for human presence using the 3D sensor and generating restart authorization signals without requiring manual intervention. The control unit continuously evaluates sensor data and autonomously determines when safe restart conditions are met, eliminating the need for human operators to physically verify zone clearance.
Solution Approach 2:
The manual mechanical verification process is replaced by an automated optical sensing system. The 3D camera and control unit form an automated detection system that substitutes human operators, using optical field detection instead of manual visual inspection to determine zone clearance and authorize restarts.
2Reliability
If protective zones are made large to cover all scenarios, then safety is improved, but productivity decreases due to earlier system response reducing machine availability
Solution Approach 1:
The system applies different monitoring characteristics to different spatial locations within the danger zone. The 3D sensor enables precise localization of objects, allowing the control unit to distinguish between static objects (like pallets) in certain areas and moving persons in other areas. This localized differentiation allows smaller, more precise protective zones while maintaining safety.
Solution Approach 2:
The system changes the parameter of zone monitoring from binary (occupied/not occupied) to spatially-resolved (position, size, movement characteristics of objects). By analyzing depth information and movement patterns, the system can differentiate between safe static objects and hazardous moving persons, enabling more precise zone configuration that improves machine availability while maintaining safety.
3Extent of automation
If 3D imaging is used to distinguish moving objects from static ones, then automation is improved, but device complexity increases
Solution Approach 1:
The system performs preliminary capture of 3D images before shutdown occurs, storing them in buffer memory for later analysis. This preliminary action allows the control unit to compare post-shutdown images with pre-shutdown reference images, automatically identifying whether objects are new (potential persons) or static (safe objects). The buffering approach enables automated distinction without requiring complex real-time processing during critical restart decisions.
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 automatic and rapid machine restarts, avoiding manual interventions and increasing productivity by ensuring safe operation without human delay.
Implementation Method 1
3D cameras using various technologies, such as stereoscopy, triangulation, time-of-flight measurement
Implementation Method 2
3D cameras using various technologies, such as stereoscopy, triangulation, time-of-flight measurement
Data Source
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AI summary
The invention relates to a sensor arrangement and a method for securing a monitoring area on a machine. The sensor arrangement comprises a camera (11) that continuously generates 3D images, a control and evaluation unit (18) for detecting the position of objects (14, 30) in the monitoring area (22) and, in the event of a dangerous position, initiating a safety-related reaction of the machine (16), wherein a buffer storage unit (28) is provided for storing the last recorded images and creating a 3D reference map from the stored images when the safety-related reaction has been initiated, a voxel identification unit (32) is provided for identifying those voxels in the current 3D image whose coordinates deviate from those of the corresponding voxels on the reference map by a predetermined distance, and a motion detection unit (34) is provided in which the voxels thus identified are then examined.whether, in the course of a specified number of further current images, these show position changes that exceed a specified threshold and, depending on this, a restart signal for the machine (16) can be output at an output (26).