Industrial robots have historically been separated from humans by cages and other types of guarding systems, protecting people from interacting with the machines. Collaborative robots, or cobots, are designed to have the ability to share the same space as human workers, taking over dangerous and repetitive tasks and learning from their interactions with humans.
A report from ABI Research, Collaborative Robotics: State of the Market / State of the Art, projected the number of industrial-use, collaborative robots sold in the U.S. to triple in the next ten years.
Are cobots safe?
Because cobots are capable of sharing the same workspace as humans, many are designed to be power and force limited in order to reduce the chance of injury from a potential collision between human and manipulator. However, manufacturers don’t know the exact environment the cobots they create will be deployed in. If cobots are integrated without further consideration for the environments they’ll be used in, the risk of harmful human/robot interaction is increased.
Two types of harmful contact can happen between people and cobots: quasi-static contact (operator is pinched or clamped between moving parts of robot system) and transient contact (operator is not captured by the parts of the robot and can move away from the robot). Differing forces affect the outcomes of both interactions. Limiting the power and force behind a robotic system ensures that if contact between human and machine occurs, no lasting harm will be done.
Mitigating risks associated with power and force cobots
This is why ISO/TS 15066 stipulates that a comprehensive risk assessment according to EN/ISO 12100 be carried out at the point of use. When the risk assessment and testing has been completed, then risk mitigation and risk reduction (such as limiting the force behind the robotic system) can begin. Besides testing the force and power limits of a cobot, companies must also evaluate the electrical integrity, the workspace environment, the software, and the cybersecurity of the robotic system. A claim by a manufacturer is not sufficient to determine compliance. A functional safety evaluation is extremely complex, and a safety control system must be evaluated and approved by a qualified testing agency.
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