AYE, ROBOT!

New-generation ‘collaborative’ robots are working ever more closely with humans, eliminating barriers and opening new opportunities for automation.

February 1, 2018

Terry Costlow

Arms on some of the latest-generation robots have many joints, affording multiple-axis dexterity and precision undreamed of in previous machines. (Credit: ABB)

Since 1961, General Motors has used robots for work described by the three Ds — difficult, dangerous or dirty. About a decade ago, GM started looking at ways to move robots from today’s highly-restricted work cells into an environment where they collaborate with humans, performing difficult and repetitive aspects of tasks so people can focus on higher value activities.

The automaker teamed up with the NASA Johnson Space Center in 2007, establishing the Robonaut 2 project to explore ways that people and robots could work closely together. In 2013, the first collaborative robot appeared in a GM plant, picking up spare tires coming from the inflator room, then stacking them on carts in close coordination with human workers.

“Collaborative robots can be used in different ways,” said Marty Linn, Manager of GM’s Advanced Robotics Technology. “They can perform traditional robotic tasks without all the space needed for guards, fencing and light curtains. They can also work in harmony with humans. In the spare tire application, people need to interact with the tires and the robot; there’s not a lot of room for fencing normally used to keep people and robots apart,” Linn explained.

Applications such as headliner glue placement have pioneered robot usage in vehicle assembly plants. (Credit: GM)

GM has since expanded to around 40 collaborative installations. Several other OEMs and Tier 1s have started implementing collaborative robots, which move slowly and sense obstacles in their path so they won’t harm people. This new class of machines is seeing quick acceptance: Technavio predicts compound annual growth will exceed 60%. Standards have helped suppliers design what are sometimes called power- and force-limited robots.

“According to the ISO Technical Specification 15066-2016 (TS 15066), on the safety of collaborative robot systems, power- and force-limiting is only one of four possible modes of safe collaborative operation,” noted Bob Doyle, spokesman for the Association for Advancing Automation (A3). Other modes include hand guiding, speed and separation monitoring, and safety-rated monitored stop. Companies also are working on sensor solutions that will enable effective speed and separation monitoring, Doyle said.

Close proximity

Robot designers have created a number of technologies that let robots work in close proximity with people. Slow movements are an important safety feature, augmented by sensors that let the robot know when it’s bumping into something. Touch-sensitive skins and sensors help robots interact safely within their work environments.

Robots increasingly are capable of handling objects, freeing their human co-workers to focus on more complex tasks. (Credit: YASAKAWA)

“To improve safety for human operators, sensors and skins of this type can even be fitted to the tools that robots use to perform specific tasks,” explained Giuseppe Colombina, Advanced Product Development Manager of Comau. “Vision systems and lasers can also enable robots to detect the presence of a human operator within their range of operation.”

Experts noted that one challenge is in determining where robots can help. Often, they’re used for holding something while humans work on it. For safety’s sake, the objects being held are fairly light, since moving heavier objects requires more force, making it difficult to stop quickly to avoid injuring a person.

“The maximum [weight] OSHA lets human workers lift during an eight-hour shift is about 17 kilos,” said Bernardo Mendez, Senior Product Manager at Yaskawa Innovation Inc. “That’s about where collaborative robots’ impact ends. If the robot does the heavy part of the job, sometimes you can reduce a two-person task into a one-person job.”

While these new machines can do some jobs without a human co-worker, they will typically co-exist in manufacturing operations with people. Many jobs require motions that are very difficult for machines to perform. Final assembly applications are seen as a significant opportunity.

“For applications that combine the strengths of human operators such as agility and fine motor skills with robot strengths such as accuracy and the ability to do repetitive tasks, collaborative robots make the most sense,” said Nicolas De Keijser, the Assembly and Test Business Line Manager for ABB Robotics. “Machine tending, testing and material preparation/kitting are other very relevant applications where robots in proximity of humans can be beneficial.”

Influencing facility design

Most collaborative robots are inexpensive compared to their larger brethren, which often require capital expenditures well into the hundreds of thousands. That’s partially because they’re often smaller, and because they don’t require barriers that keep people from getting close.

Sensitive skins on work arms keep robots from injuring workers. (Credit: COMAU)

GM is using them for tasks like dispensing adhesive for attaching foam blocks in seat headliners to minimize the effect of head impact collisions. They’re also used for windshield installation, typically manipulating the glass and applying adhesives.

To complement these robots’ low cost of entry, developers are also making the machines easy to use. They can be programmed using apps and intuitive programming tools, or they can be moved through the steps of a job. The latter teaching method lets operators quickly personalize the machine’s movements.

Now that these automatons have proven their worth, skeptical and cautious manufacturing strategists are predicting a major impact in global manufacturing. Their impact could become as great as that of conventional robotics. The automotive industry, which represents approximately 70% of the robotic market according to A3, will be a major driving force.

“Collaborative robots will change the way companies lay out automotive assembly lines,” Mendez at Yaskawa Innovation said. “They will be one of the biggest influences in how manufacturing facilities get created.”

GM, which has deployed more than 30,000 robots, plans to be at the forefront of this new technology.

“This is really changing our culture and our understanding of what it means to use robots,” Linn said. “Over the last three years, we’ve gone through a learning curve period, working with integrators and operators to understand new application spaces that can use robots and areas where they are not helpful.”