A quick guide to collaborative robot safety
Manufacturers in a wide variety of industries employ collaborative robots (shortened to “cobots”) to reap the benefits of integrated safety features that allow these robots to share tasks with humans and flexibly adapt to new requirements of new repetitive tasks. Although safety is a key feature of their design, cobots still require risk assessments.
Technologies such as force feedback, low-inertia servo motors, elastic actuators and collision detection technology limit the power of cobots and force capabilities to levels suitable for contact. More compact than conventional robots, cobots generally have lightweight frames with soft, rounded edges and minimized pinch points.
What safety standards apply to collaborative robots?
The safety standard ISO 10218 and technical specification RIA TS 15066 define the safety functions and performance of the collaborative robot. Under TS 15066, the force and speed monitoring of the cobot is set based application data, human contact area, and workspace hazards.
Application data, possible human contact and workspace hazards all factor into the calculated safety settings based on TS 15066. Manufacturers who are unfamiliar with these safety standards can hire a safety assessment provider to make the calculations and offer suggestions for improving the safety of the overall collaborative application.
Key safety considerations for hand-guided teaching
ISO 10218 and ISO/TS 15066 provide standards and guidance for collaborative robot teaching functionality. Many collaborative robots, such as Omron’s TM Series robot, employ intuitive hand guiding mechanisms for teaching new tasks without the need to explicitly program the movements of the robotic arm.
Hand guiding mode monitors force and speed to ensure that the teaching process complies with safety standards. During design and safety setup, manufacturers must ensure that hand guiding can only occur after (1) the robot has stopped, (2) intentional mode selection has occurred, and (3) speed and force monitoring are active.
Key safety considerations for the collaborative workspace
Collaborative robots perform automated tasks around other equipment that could potentially cause harm. The area in which a collaborative robot operates, including any tooling or additional equipment, is known as the collaborative workspace.
Manufacturers should list and map out all additional equipment in the complete collaborative automation project, making sure to evaluate each device for potential hazards and safety sensors to use prevent human and equipment damage. In addition, the collaborative workspace must be clearly marked.
Designers of automated machine tooling, material handling and assembly applications must consider all the ways in which a collaborative robot might interact with an operator, what aspects of the surroundings might cause clamping or entrapment, and what characteristics of the end-of-arm tooling might pose a risk due to high heat, sharp edges or other hazards.
If a risk assessment is performed thoroughly and requisite safety measures are implemented, it will maximize the efficiency gains of an application and boost performance.
To read the full article written by Tina Hull, TUV Functional Safety Expert and Product Engineer, and Darrell Paul, Market Manager of Robotics and Motion, at Omron Automation Americas, please visit Tech Briefs website here.
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