Collaborative robots (also known as cobots) are changing how robots and humans interact in our factories and manufacturing facilities.
No longer separated by cages, humans and cobots can work beside each other on complex tasks from picking and placement to assembly and logistics.
Human-cobot systems bring together the best of human capabilities (complex reasoning, ease of learning new tasks, pattern and object recognition in cluttered environments) and robot functionality (the ability to perform complex, tedious tasks 24/7 and with high precision).
The close proximity between humans and cobots and its advantages are exciting for manufacturers, SMEs, and the robotics industry, but it also brings a unique set of safety challenges.
One of the central ideas behind ISO/TS 15066 is that if contact between robots and humans is allowed, and incidental contact does occur, then that contact shall not result in pain or injury.
Published earlier this year, ISO/TS 15066 was six years in development and is the product of an International Standardization Organization committee containing members from 24 participating countries, including representatives from leading cobot manufacturers. The document provides comprehensive guidance for those conducting risk assessment of collaborative robot applications.
As a result, every person involved in the design and implementation of cobot systems from manufacturers and application engineers through robot integrators and production managers should be well read on ISO/TS 15066.
In the case of Honda, ISO/TS 15066 has already had a real-world impact. The firm uses cobots for safety rated monitored stop applications –applications that enable robots to be loaded by human workers without the servo needing to be shut off.
When they started implementing the system, the first thing they showed their associates was the then draft of ISO/TS 15066, says Dave Smith, a robotics safety expert at Honda Canada Manufacturing and expert contributor to ISO/TS 25066.
“We showed them in the standard why these robots are different, because they are used to the robot being locked down during loading. We used ISO/TS 15066 to show our associates the requirements and all the different features that are keeping them safe. We will do the same with power and force limited applications,” says Smith.
Implementation of ISO/TS 15066 allows application engineers, integrators, and production managers to demonstrate the safety of the system to end-users, improving factory floor worker's confidence in the process.
Below, we touch on some key information from the new standard:
Pain Onset Level Data
Researchers at the University of Mainz, Germany, conducted a pain onset study on behalf of the ISO committee.
The study involved 100 subjects and was designed to establish force and pressure limits on 29 body areas. Using this information, ISO/TS 15066 provides a list of maximum force and pressure levels for each part of the human body. This information establishes a set of force/pressure thresholds that the robot should not exceed and is intended to guide robot design and integration.
Maximum Allowable Robot System Power/Speed
ISO/TS 15066 outlines recommended power and speed limits for collaborative robot systems intended for power and force limited operation.
This section of the document provides the guidance required to determine the maximum allowable speed to set the robot at, such that the end of arm tooling (EOAT) and part don't exceed the maximum for the robot system.
ISO/TS 15066 describes the different design criteria that robot system and robot tool manufacturers should introduce into their designs. This provides guidelines for manufacturers that had difficulty distinguishing between what was and what wasn't a collaborative robot system.
Building on the information contained in existing robot safety standards ISO 10218 (Part 1 and Part II), ISO/TS 15066 describes four main techniques for collaborative operation: a) safety rated monitored stop b) hand guiding c) speed and separation monitoring d) power and force limiting.
Widespread Impact and Benefits of Cobots
By standardizing these qualifiers and providing clear guidelines on how cobots can be safely used, ISO/TS 15066 is set to benefit many parties, from the robotics industry to end-users.
(Image courtesy Robotiq.)
Collaborative robotics are a “game changer” says Roberta Nelson Shea, convenor of the ISO Industrial Robot Safety Working Group (ISO/TC 299/WG 3) and global marketing manager for Rockwell Automation.
“It has opened peoples’ eyes to the notion that they don't have to completely stop and remove power from equipment in order to say it's safe for people to have some degree of interaction with it. For full automation, the game changer is that you can keep power on, but can safely control the situation, so that a person is not hurt.”
Factory floor space has a higher value assigned to it than any equipment you could fill it with, says Shea, and collaborative robotics solutions take up considerably less space than traditional industrial robots.
“The costs of heating, plumbing, and maintaining that space, are higher than the value of the equipment you put in. So if we can decrease the floor space that's required, by safely implementing collaborative robotics we have the possibility of decreasing the cost to a user.”
The concept of human-robot collaboration is designed to improve productivity and maintain worker safety, explains Jeff Fryman, a robot safety consultant, who served as Director of Standards Development at the Robotic Industries Association for 17 years.
“This concept has been out there for several years now, little understood and loudly imitated with maybe very inappropriate solutions. Finally, we have a document that we can point to that says 'These are the limits that you can apply to your design'.”
ISO/TS 15066 provides guidance that robot integrators need to think of when installing a collaborative robot, says Lasse Kieffer, Global Compliance Officer at Universal Robots, who also worked on the ISO/TS 15066 document.
“If you are an integrator that is quite new in the field and you don't have that much experience, then ISO/TS 15066 is very good because it provides the input you need to do a good risk assessment.”
“It also mitigates risk if you follow the document and you are more certain that you do things right,” adds Kieffer. “There can also be benefits from stating that products comply with a safety document. Sometimes this has a commercial value or a value in terms of allowing you to show that you performed your risk assessment correctly.”
Additionally, knowing that the specifications laid out in ISO/TS 15066 have been followed will generate confidence among factory workers, says Björn Matthias, senior principal scientist on robotic automation at ABB.
“The factory worker can be confident that his colleagues responsible for creating the application (the production manager and the application engineer) have worked according to the best present knowledge of the state of the art. This should give him a degree of confidence in his workplace.”
Fryman agrees. “As a user, to know that there is a set of technical specifications that the integrator is designing toward, should give workers some comfort in the knowledge that someone is not just winging it and that the system has been designed within acceptable parameters. This should make factory workers more comfortable with the concept. The worker comes to work in the morning healthy, he's entitled to go home at night safely.”
Common Mistakes, Tips and Insights on the use of Cobots and ISO/TS 15066
We asked ISO's ISO/TS 15066 experts for their tips and insights regarding implementation of these new technical specifications.
If you have never carried out a risk assessment before, begin with some basic background research, says Kieffer. “I would use ISO 12100 as a base document. At least look through it to get some basic ideas about how to perform a risk assessment. Then I would use the ISO 10218-2 standard and, finally, I would use ISO/TS 15066 to do a comprehensive and reasonable risk assessment.”
One of the most common misunderstandings around power and force limited cobot systems is that some people assume that they can “tear down all the fences and everything is wonderful,” says Shea. This is a false assumption.
“The big thing that people have to be reminded of is that it's not about the robot, it's all about the application. I might have a power and force limited robot that can only exert “x” force and would not hurt a person, but if that robot system is packing knives, it's not a suitable candidate for a collaborative application.”
Smith agrees, stressing it’s important to understand whether a robot is really necessary.
“You have to realize that even if it's a small, power and force limited robot with a low payload, that doesn't mean that it's risk-free. You have to understand what the application’s risks are going to be.”
The two most common mistakes made during robotics-related risk assessments are oversimplifying or over-complicating the process, says Dominguez.
“I've seen risk assessments where they try to outline in detail every single piece of the application without simplifying and grouping and the analysis becomes so burdensome that you can't picture the basic requirements. I've also seen cases where a very simple approach has been taken, resulting in very brief risk assessments that don't address critical tasks and exposures.”
To avoid analysis paralysis, companies thinking about implementing cobot solutions need to decide the degree to which they build up in-house expertise, explains Dominguez.
Companies considering small collaborative robot solutions (1-2 robots) should get an experienced integrator to perform the risk assessment. Meanwhile, big factories planning major installations of 10 or 20 collaborative robot systems should “empower people to learn.”
“Get some help in the beginning, but educate your people enough to do it on their own,” Dominguez explains. “If you do this, you'll be able to fine tune your applications better, because you'll have better control.”
So, whether you are an integrator, a production manager, or an application engineer, the new technical specifications under ISO/TS 15066 provide essential, data-driven information and guidance needed to evaluate and control risks and support risk assessments for cobot systems and applications.
In a broader sense, ISO/TS 15066 is likely to inspire further advancements of protective device technology, better sensors, improved motion control and other innovations.
Finally, ISO/TS 15066 is a work in progress. The ISO committee would He is also a regular speaker at international events on robotics technology and business.be looking to receive feedback from those that have used the document. To do so, please send your comments to email@example.com.
This article consists of edited extracts from Robotiq’s eBook “ISO/TS 15066 Explained”
Samuel Bouchard is President of Robotiq
, a fast growing robotics company based out of Quebec City, Canada, that he co-founded in 2008.
The company's focus is commercializing advanced grippers and sensors for robotic systems. Mr. Bouchard holds a Ph.D. in mechanical engineering and a bachelor in Engineering Physics from Laval University, in Canada. He is also a regular speaker at international events on robotics technology and business.