Fenceless Robot Sensor Positioning for Obstruction Avoidance
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Solution Overview
Problem
Existing industrial robot systems face challenges in distinguishing between robot movements and human presence within the working area, as sensors are often obscured by the robot arm and are costly due to the use of multiple laser scanners, which are expensive and inefficient.
Innovation Solution
The system employs two sensors configured to detect motions within a 90° horizontal plane, with adjustable arms that move independently of the robot arm to position them outside the working area, allowing continuous supervision of safety zones and reducing the number of sensors needed by covering a 360° angle with two sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple laser scanners are used to cover the working area, then safety zone detection coverage is improved, but system cost increases
Solution Approach 1:
The patent employs movable arms that can dynamically reposition the sensors between a retracted position (during robot operation) and an extended position (for safety monitoring). This dynamic positioning allows two sensors to effectively cover areas that would otherwise require multiple fixed sensors, reducing system cost while maintaining safety coverage.
Solution Approach 2:
The patent extends the monitoring capability into a third dimension by using vertically extendable arms. The sensors can be positioned at different heights and angles, creating a three-dimensional safety monitoring volume. This dimensional approach allows two sensors to cover the entire working area more effectively than multiple sensors positioned only in a single plane.
2Area of stationary object
If sensors are positioned close to the robot for compact installation, then space utilization is improved, but sensor obstruction by the robot arm occurs
Solution Approach 1:
The movable arms enable the sensors to dynamically change their position relative to the robot. During robot operation, the arms can extend to position sensors outside the robot's working envelope, preventing obstruction. When not monitoring, the arms retract to minimize space usage. This dynamic adjustment resolves the conflict between compact installation and unobstructed sensor detection.
3Adaptability or versatility
If the robot working area extends outside the movable platform, then operational flexibility is improved, but sensor distinction between robot and human becomes difficult
Solution Approach 1:
The safety control unit is pre-programmed with knowledge of the robot's working area boundaries and characteristics. Before safety assessment, the system has established reference information about normal robot movements and positions. This preliminary information allows the control unit to distinguish between robot-induced sensor signals and human intrusion, even when the working area extends beyond the platform boundaries.
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 configuration effectively avoids sensor obstruction by the robot, reduces costs by minimizing the number of sensors required, and ensures comprehensive safety zone coverage, enabling safe and efficient operation of industrial robots in fenceless environments.
Implementation Method 1
a sensor system comprising two sensors (4, 5) arranged to detect motions within an angle of at least 90° in a horizontal plane
Data Source
AI summary
The present invention relates to an industrial robot system comprising a platform (1) positioned in a robot cell, an industrial robot (2) positioned on the platform and including an articulated robot arm (6), a sensor system comprising 5 two sensors (4, 5), wherein each of the sensors is configured to detect motions within an angle of at least 90o in a horizontal plane, two arms (10, 12) attached to the platform (1) and arranged to move the sensors (4, 5) in relation to the platform independent of the articulated robot arm between an extended position located a distance of a least 0.5 m from the platform and a 10 retracted position. The sensors are arranged to detect motions of an object within a safety zone and the robot system is configured to adjust the speed of the robot if a moving object is detected in the safety zone.