How to Safely Implement Collaborative Robots

Dec. 16, 2019
As collaborative robots continue to be introduced in manufacturing, some key safety hazards need to be addressed before collaborative robots can be safely implemented on the line.

The introduction of collaborative robots (cobots) in manufacturing has presented some unique safety challenges for production workers, engineers, managers, and safety professionals. In my opinion, cobots represent the ingenuity driven by continual process improvement for safe and sustainable work.

An integral part of the manufacturing process is our environmental, health, and safety stewardship. Cobots have been shown to help improve safety and health while addressing efficiency, scale, and other production requirements. Cobots are not the same as industrial robots, which are typically much larger and require a significant amount of fixed and interlocked engineering controls. Industrial robots, while good for some heavy industrial applications, are often too costly for some companies’ budgets or too large to incorporate into a smaller scaled assembly line.

Cobots have a smaller footprint. They typically cost less to implement—which is an attractive option for many outfits. According to the robotics business review through ABI research, the cobot market is expected to surpass $11 billion dollars by 2030. Safety professionals should understand the hazards associated with cobots and be prepared to train workers on how to mitigate them. Managers and supervisors should also be prepared to qualify users with hands-on training programs. Having a strategy prior to implementation makes all the difference when critical production factors and seamless integration are important.

When I approach a machine safety hazard, I look at distance as one of the factors for mitigation. Distance is used to mitigate a wide variety of hazards including chemical exposures, ionizing radiation, and fall hazards.

Take ionizing radiation for example: Distance, time, and shielding are mitigation techniques used to keep exposures as low as reasonably possible in the nuclear and medical industries. These same techniques can also apply to industrial robotics. Keeping workers away from industrial robots through interlocked devices (time) and physical guards (shielding and distance) is a common practice. 

From stage left, enter the cobot.

Cobots are different in that humans are expected to be within the traditional hazard envelopes as they work with the cobot. Programming allows the cobot to learn its boundaries, maximize operational space, and restricted modes. Programming also restricts the cobot’s speed to a standard and safe limit standardized by organizations like the American National Standards Institute (ANSI), International Standards Organization (ISO), and the Robotics Industries Association (RIA). Artificial Intelligence (AI) is also being used with cobots to allow it to understand magnitude of force requirements for specific tasks for production—like picking up a soft fruit vice a hard rock or making efficient decisions about production.

AI can also allow the cobot to detect changing workspace conditions, like when a human is too close or when products it is picking up are disorganized. The cobot can have autonomous control over collision avoidance with other objects it detects. In case the programming fails, human coworkers are trained on and can access emergency stops to immediately shut down the cobot. Since cobots are programmed and designed to use less force and speed in their movements, it reduces the severity of inadvertent contact with workers. Although cobots do not eliminate the potential for contact, it is interesting to note how they may drastically decrease muscular skeletal disorders that share a large percentage of work injury claims. The residual risk from cobots may outweigh the risk created by repetitive motion and improper lifting. It is best to determine this for specific situations through a formal risk assessment.

There is still much to research with cobots, specifically their use of AI. Considerations should be given to the impact of this technology on aspects of production, specifically worker health and safety. There is limited information from the Occupational Safety and Health Administration (OSHA) on cobots, other than compliance directives toward the inspection of facilities.

Regulation of cobots is still based on the need to comply with horizontal OSHA standards which address the recognizable hazards that workers may be exposed to. Currently, consensus standards that address cobots offer the best standardized guidelines for worker health and safety.

It is always best practice to have trained and experienced programmers and integrators work on your cobot upgrades, as it will affect worker safety. Worker training should also be performed by qualified safety and health professionals or other experts who can adequately prepare workers for the hazards they may be exposed to.

Editor's note: Learn about P&G's application of cobots here.

Jonathan Shaffer is a corporate safety engineer at Optimation Technology, a certified member of the Control System Integrators Association (CSIA). For more information about Optimation, visit its profile on the CSIA Industrial Automation Exchange.

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