Robot Safety Device with Dual Sensor Ranges for Collision Avoidance
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Solution Overview
Problem
Existing safety devices for industrial robots lack the capability for early detection of objects approaching, limiting the traversing speed and preventing targeted speed reduction or collision avoidance, thus restricting operational performance.
Innovation Solution
A two-stage safety device with extended sensor ranges, including a capacitive sensor on the robot and a second sensor outside the robot's range, creates an intermediate zone for early collision detection, allowing for adaptive speed reduction and potential stoppage before collisions occur, ensuring safe operation with high performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a close range sensor device is used to ensure safety, then collision detection reliability is improved, but the traversing speed of the robot must be limited due to the short detection range and braking distance
Solution Approach 1:
The monitoring space is segmented into multiple zones using two different sensor devices: a first sensor device (e.g., capacitive sensor) monitors a first space at close range, while a second sensor device (e.g., laser scanner) monitors a second space at a larger distance. This segmentation allows the system to detect objects at different distances and apply appropriate speed reductions for each zone, thereby maintaining safety while enabling higher traversing speeds.
2Reliability
If the traversing speed is reduced to allow safe stopping distance, then collision avoidance capability is improved, but operational performance and productivity deteriorate
Solution Approach 1:
The robot's traversing speed is dynamically adjusted based on the detected object's distance and position. When an object is detected in the first space (close range), the speed is reduced to a first value allowing safe stopping. When an object is detected in the second space (larger distance), the speed is reduced to a second value that is higher than the first value but still safe. This dynamic speed adaptation maintains collision avoidance capability while maximizing operational performance.
3Reliability
If redundant sensor devices are used to ensure safety, then detection reliability is improved, but device complexity increases
Solution Approach 1:
The control device serves multiple functions: it controls the robot's motion, processes signals from both sensor devices, determines object distances, and dynamically adjusts traversing speed based on detection results. By making the control device multi-functional, the system achieves reliable detection using redundant sensors without proportionally increasing overall system complexity.
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 timely detection and prevention of collisions, allowing the robot to operate at reduced speed or performance when objects are detected at a distance, and return to normal speed when clear, thus enhancing safety and performance.
Implementation Method 1
the other sensor device is developed particularly as a capacitive sensor device, which records a close range about the industrial robot
Data Source
AI summary
A safety device is described for a handling apparatus, particularly an industrial robot, having at least one movable gripping arm and a gripping device situated on the gripping arm, as well as having a first sensor device, connected to a control device, that is associated with the gripping arm, for collision detection. The first sensor device includes a first recording range. The safety device includes a second sensor device connected to the control device and including a second recording range. The second recording range records a range which has a greater distance from the handling apparatus than the first recording range. Both recording ranges extend outside the handling apparatus.