Technical advances in microprocessors, artificial intelligence techniques, and automation and control systems have ushered in a new age of robotics. Despite breakthrough applications from manufacturing to medicine, robots carry risk. Without proper precautions in place, a robot experiencing a fault or failure might cause serious injuries to people and damage to capital equipment in or around the work cell.
To address this risk, stakeholders in the robotics and automation industries are developing new international safety standards through the International Organization for Standardization (ISO) for robots and robot systems integration. ISO 10218-1, the initial updated standard published in 2006, details requirements and guidance for safety in design and construction of the robot itself, not the entire robot system. Part 2, ISO 10218-2, which should be published in 2011, covers the integration and installation of a robot system or cell. Together, these standards give a more comprehensive set of requirements for robot safety.
While much of a robot’s role contributes to worker health and safety, two attributes – the power to handle super-human payloads and the flexibility enabled by full range of motion – pose potential dangers to people, especially if a fault or failure occurs.
The current U.S. robot safety standard ANSI/RIA R15.06, adopted in 1999, does not cover innovations developed since then. The team drafting the new international standards includes Americans representing the U.S. Robotic Industries Association (RIA). Once global experts confirm the new international standards, the RIA is expected to update R15.06 to comply with the new ISO criteria.
Among the changes to be included in the updated standards are first-time safety requirements for four new robotic technologies: wireless teach-pendants, human-robot collaboration, robot-to-robot synchronization, and vision-based safeguarding systems.
Wireless teach-pendants. Traditionally, a cable connected the robot controller to the pendant. Wireless technology eliminates the cable. To prevent confusion about which pendant controls a specific robot, the new ISO standard includes requirements for unique identification of wireless devices. Therefore only one wireless pendant can be used per robot to prevent unintended operation of another robot that may result in a hazard to personnel.
Human-robot collaboration. If an operator needed to interface with the robot, older safety control systems confirmed whether the robot was in a safe state or safe position, which typically meant limiting its motion or bringing it to a full stop and removing its energy source. But this approach slowed productivity.
Collaborative robots, called “cobots,” work side-by-side with people. New software-based safety systems can slow a robot to a safe speed or direct robot motion to a safe position or a safe state, allowing people to share the same workspace with far less risk. Environmental awareness sensors let cobots “see” the operator co-worker, which triggers the robot to go into a safe position or safe state, and “wait” in safe mode until the operator moves out of the range and resets the motion.
Robot-to-robot synchronization. New technology allows a maintenance person to use one controller and one teach pendant to coordinate the actions of multiple robots, typically four per teach pendant.
Vision-based guard systems. A 3-D safety-rated vision intrusion system can keep robots and people separate in the workspace without the costs and hazards involved with perimeter fencing. Such an electronic and programmable perimeter guarding system includes three video cameras mounted overhead in the work cell, which can detect when someone enters the hazard zone. The system then signals the intruder about the danger through a visual or audio warning. The system also signals robots in the space to slow down or stop. Once the hazard zone is clear, the robots are reset and operations can safely resume.
A robotics safety white paper examines these advances in robotic safety standards and explains how these technologies will help industries better protect workers while helping increase plant efficiency and productivity. It also details the important role of integration technology in helping safeguard robotic systems and provides insight on future trends in robotic applications and associated safety issues.
Rockwell Automation
www.rockwellautomation.com
::Design World::
Filed Under: Factory automation, Motion control • motor controls, Mechatronics, Safety systems + components
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