Modern industrial robots have distinct advantages over humans in terms of physical strength and longevity, and they are ideal for performing repetitive tasks with a degree of speed and precision that human beings simply could never match. But the high speeds, and often weighty payloads, make them dangerous to be around. When it is working, a heavy-duty industrial robot is oblivious of everything except the task for which it was designed, leaving the onus on human beings to stay out of the way or risk a serious injury. As useful as they are in certain contexts like automobile manufacturing, it is unsafe for industrial robots and human beings to work in the same area at the same time. A limitation that up until now has deprived manufacturers of the efficiency improvements associated with ‘mixed’ production.
Enter the cobot
Collaborative robots (cobots) are robots designed to work as assistants in conjunction with human operators on the same production line. Unlike traditional industrial robots, which have to be surrounded by screens and guards to protect workers during operation, cobots are designed to coexist safely alongside humans in the factory environment. Safe (human-friendly) operation and ease of programming are the standout features that distinguish modern cobots from their industrial counterparts.
Safety is achieved through the multiple sensor systems that collaborative robots use to detect the presence of a human co-worker. In the event of an unavoidable collision, the cobot will immediately shut down so that the human operator feels nothing more than a gentle nudge. The cobot also has rounded surfaces which make the nudge event gentler, and all pinch points have been eliminated. Limiting the speed and payload are other safety related measures. According to the manufacturers, the ideal speed is something akin to human speed.
Programming is accomplished through ‘teachable-learning’, which eliminates the need for the advanced computer programming skills often required to set up a traditional industrial robot. To program a cobot, the operator simply places it in ‘teach’ mode and then guides its limbs manually through the appropriate motions. The cobot remembers the movements and re-executes them when it is switched into ‘work’ mode. This ease of setup makes collaborative robots ideal for short-run production lines where reprogramming may be required several times in a single day.
Manufacturers now have a way to automate their mixed operations, a task for which a large high-speed industrial robot is completely unsuitable. The smaller and easy to program cobot, on the other hand, is ideal for flexible manufacturing environments as it can be moved from line to line or job to job as and when required.
Cobots in action
Rethink Robotics is a company with the vision to provide manufacturers with an entirely new type of automation. The company’s latest offering, Sawyer, is a high-performance cobot designed for machine tending and other precision tasks.
GE Lighting, an early Sawyer adopter, has installed the friendly looking cobot on the production lines at its Hendersonville plant. Sawyer positions parts into a light fixture and then allows a human GE colleague to complete the assembly. The company needed to ramp-up production in a hurry in order to meet orders for tens of thousands of new LED fittings to replace the old lights on the city’s streets and highways.
This is a prime example of a cobot working side by side with a human being to improve the efficiency on a production line. Far from threatening the job of the human operators, Sawyer makes life easier for them and frees them up to focus on the cognitive aspects of the task.
Cobots are lower in cost than traditional industrial robots and are aimed at the small to medium sized companies that make up 70% of global manufacturing. Nick Denbow has more in 'Nick Denbow's European report: The latest robots are friendly'.
Steven Meyer
Editor: SA Instrumentation & Control
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