Rules of Collaboration
Will new developments in technology allow safe robot and human interaction on the plant floor?

Written by Scott Bury

Robotics is poised to spring into new applications and markets, from medicine to personal care to manufacturing. But outmoded safety standards that prevent humans and robots from working together in a collaborative environment are getting in the way. “The gap between the heavy industrial robot and the assistive, R2-D2 type that works with humans is getting narrower,” says Mike Callardo, vice-president, product management with ABB Inc. “The typical robot is changing,” agrees Kevin Kosuszek, director of marketing with KUKA Robotics. “It’s not quite Rosie the Robot, but it’s getting closer to that.” The “next generation robot,” an initiative of the Robotics Industries Association (RIA), seeks to develop not only the technologies but also the rules and safety standards that will dramatically lower the cost of implementing robotics and broaden the range of applications for robots, including those that require closer collaboration between robots and humans. The benefits include greater productivity, achieving lean manufacturing goals and assisting humans in a wider range of activities. New applications in manufacturing Dynamic limit switches, stereo vision cameras that can perceive a three-dimensional workspace, capacitive and other non-touch sensors, tactile sensors, advances in servo motors and myriad other recent technological advances all play a part in the development of the new generation, lean, collaborative robots. But the biggest change is a new way of looking at how we can use robots and what they can do in a number of different environments. In a presentation to the International Robots & Vision conference in Chicago last June, Jeff Fryman, director of standards development with the RIA, listed a number of new features of the next generation of robots: wireless pendants or control pads; control of simultaneous motion of synchronous robots or of multiple axes of motion, and; collaborative robots that include humans in the control or decision-making “loop.” Another key aspect of this advance is the idea of safety-rated soft limits. Rather than hardwired e-stops for safety, new generation robots will include “safety-rated soft limits” that can adapt to the situation, stopping or limiting motion to protect people who come too close. These technologies could usher in a new range of collaborative workspaces where humans and robots work closely together, including fine assembly, spot welding in limited spaces and tasks in unstructured environments or with variation. “There are still some jobs that humans do better than robots,” says Trevor Jones, president of the RIA and director of OEM business development with Thermo Electron Corp., Laboratory Automation and Integration in Burlington, Ont. “A human is also much better at going into a robotic workcell and clearing an error to allow the robot to start working again.” Restrictive safety standards But the very standards designed to protect the safety of human workers and machinery operators often prevent the increased use of robots. Current standards — ANSI/RIA R15.06-1999, the American National Standard for Industrial Robots and Robot Systems–Safety Requirements — don’t allow robots to operate in close proximity to humans. A robot’s workspace must be separated from any human workspace, guarded by fences, cages or even walls, and all automatic operations must cease as soon as a human enters the workspace or otherwise comes close enough to be injured by a robot. “Current standards demand that the robot stop completely when the human is in the robot’s range of movement,” explains the RIA’s Fryman. Today, robots must be built with hard-wired, full e-stops to their main axis of movement. “There are robots that can provide lifting power under the guidance of the human operator, but when the human is in contact with the machine, it must go out of automatic mode,” he says. In automotive assembly operations, for example, a “collaborative robot” can provide the power to lift heavy components, while a human operator guides them into place. However, in this application, the machine is not operating in automatic mode — it’s not a robot. “Basically, the direction has been to prevent close human interaction with the robot whenever possible,” said ABB’s Callardo in a presentation to the same International Robots & Vision conference. “In early years, ‘safe’ meant higher fences, more e-stops and more ways to keep humans away from the automation.” But greater clearances require more floor space and higher costs. These rules prohibit laboratories from using robots for repetitive tasks because they would be working right next to people. Few laboratories have enough room for a robotic workcell surrounded by a mesh cage. The current standards also prohibit the use of current robots for human assistance. It’s all in the name of protecting human operators, but at the same time, the standards limit the development of robots that really work with humans. “The safety protocols have added to the cost of implementing robots, and that has not helped increase the use of robots in North America, or helped boost North American manufacturers’ productivity or global competitiveness,” says Jones. A new way of thinking about safety Jones says the current standards are now obsolete. “Current safety standards are prefaced on the arranged in redundant arrays, with e-stops built into the hardware. You can’t put a lot of software in the safety chain under the standards,” he says. As a result, the robot standards don’t allow the use of some of the best, most advanced technologies and features. A good example is the requirement that industrial computer networks be hard-wired with redundant safety alarms, prohibiting the implementation of the “wireless plant.” “Technologies exist today to allow safe, closer collaboration between robots and human workers,” Jones says. He believes it’s time to rewrite the standards to adopt new technologies and new software. “Safety is still priority one in manufacturing, but we have to start to think in new ways.” Callardo agrees. Implementing the “next-generation robot” — the type that works closely and safely with humans — requires “a different thought process,” he says. “Currently, the robot has to be programmed so that when a human is in the workspace, the robot can’t move in there. E-stops and limit switches must be on the robot. “Does the robot have to stop in the presence of a human?” he adds. “What about slowing down when people are near, or moving only in a restricted path? Implementing collaborative robots requires a different thought process. The current standards are too restrictive, and that makes robots too costly for wide application.” Callardo suggests that, for example, stop controls programmed into the servo programming of the robot would provide redundancy required by safety standards, and feedback loops would let the robot itself know where it is in space, in relation to its workcell and to humans. “Safety is still key,” says Kozuszek of KUKA Robotics. “But the good thing about safety standards is that they’re updatable, which is why we’re working with RIA on a new standard.” The RIA has drafted a new standard proposal, which is now before ISO for review. ISO 10218-1: 2006 was published on June 1, 2006 and is now pending adoption in the U.S. Following that, ISO 10218-2–Robot system – installation and use, is still under development and may be ready for adoption in 2008. Fryman explains that the new standard incorporates software stops and multi-axis limit controls. It allows close collaboration, to the point where a human operator can touch the operating robot — within clearly defined limits, of course. A new age of robotics? Collaborative workspaces would allow manufacturers — and other industries, as well — to make even greater use of the respective strengths of human workers and robots: the power and precise repeatability of robots and the flexibility and adaptability of humans. New applications will include robots assisting humans in assembly operations, holding parts for welding and other operations, and learning and performing variable tasks. Safety standards that allow humans to touch operating robots will finally make “service robots” for personal care applications a reality. New standards will decrease the cost of actually using robots, leading to wider adoption and new kinds of applications that haven’t been thought of yet. But most important, they’ll allow businesses to decrease their costs, improve their quality and increase their competitiveness in this global economy. Scott Bury is a freelance writer based in Ottawa, Ont.

 

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