Collaborative Robots in Manufacturing

A collaborative robot, or cobot, is a type of robot intended to physically interact with humans in a shared workspace. These robots are usually designed for a specific task and come in handy when floor space is limited. A truly collaborative robot, like the ones produced by FANUC, Universal, OB7, AUBO Robotics, Omron, and KUKA, can be operated right next to a person without safeguarding.

But be warned. Just because you can operate a robot right next to a person does not mean you should. While a robot itself might be defined as collaborative, its application might not be. For example, if a collaborative robot has a knife on the end of its arm to cut a shape out of a piece of paper, then by code it might not have to be guarded; however, if it is using a knife that is sharp enough to cut someone, it would be dangerous and irresponsible not to put safeguards in place to protect the people around the robot.

MJ Engineering was once asked by a potential client to integrate a cobot that picked up hot plates measuring more than 200°F. The prospective client thought safeguarding was unnecessary because it was a “collaborative robot.” Not willing to compromise on safety, MJ Engineering insisted on adding safeguarding to its project plan, even though it meant losing the project to a lower bidder. You can count on MJ Engineering to always do the right thing—especially when it comes to safety.

Cobot Safety Categories

To make them safer to operate around humans, cobots are designed to exert a controlled amount of force that will not cause injury in the event of a collision with a person. For that reason, cobots are limited in the weights and speeds they can handle. Most collaborative robots on the market today have weight capacities between 6 and 10 kg. FANUC offers a 35-kg capacity cobot.

The International Organization for Standardization (ISO) and American National Standards Institute (ANSI) break down collaborative safety features for robots into the following four types:

  • Power and Force Limiting—This type of robot can work alongside humans without any additional safety devices.
  • Hand Guiding—This type of cobot can be used to read forces applied on the robot tool. This application is used for hand guiding or path teaching and can only be used while the robot is performing a particular function. For other functions, it will need to have safeguarding in place.
  • Safety-Rated Monitored Stop—All movement stops when a human has entered a predetermined safety zone.
  • Speed and Separation Monitoring—Movement slows as a human enters a predetermined safety zone and eventually stops if the human gets too close. It does not need a worker to give the go-ahead to resume movement.

“Danger, Will Robinson!”

Do not confuse cobots with industrial robots that are integrated with control systems designed to slow down or stop if a person gets too close. Industrial high-speed robots can handle full payload and full movement, and they will go back to full speed as soon as the person moves away. They do not meet the Robotic Industries Association (RIA) code requirements for collaborative robots.