New Robotic Technologies Address Safety Concerns

Feb. 12, 2013
Low-speed, low-skill robots are making significant inroads into a number of markets because of the robots’ ability to work collaboratively with humans.

Common industrial robots perform specific, repetitive tasks quickly and in high-volume but historically are expensive and have significant integration requirements. They also exert forces that prohibit operators from entering the work envelope. However, an emerging class of more affordable robots requires little to no integration or programming. While these newer robots cannot compete on speed or precision, they have the distinct advantage of being co-located with humans.

These human-assisting robots are low-speed and low-skill but perform cooperative tasks like picking and placing. Due to significantly lower prices and integration requirements, these robots are viable for small- and medium-sized businesses with limited automation skills and budgets. In the mobile solutions space, for example, such robots are gaining traction against traditional automated-guided vehicles and fixed conveyor applications.

Other applications for these robots range from one supplier’s coordinated robotic fleet to another’s driverless forklifts.

These robot innovations have pushed automation into previously resistant markets.  A key selling point is that users can be trained to work with these robots for “out-of-the-box” applications in a matter of days, rather than months, because less integration is required.

Safety Standard Compliance

Until very recently, the dangers associated with working alongside robots greatly limited use of the technology. Now industry is using safeguarding strategies that evaluate the use of equipment from a task-oriented perspective (i.e., how an operator interacts with machinery).  This task-oriented approach lends itself to the use of an integrated system that relies on intelligent automation components.  This minimizes the risk of operator injury to a tolerable level in specific operational modes of the machine, while allowing the operator to work more efficiently than would otherwise be possible using absolute safety measures such as physical guards and interlocks.  These modern safety systems allow operators and maintenance personnel to access a machine’s work zone by setting programmable limits on actuator speeds, forces and torques to mitigate the risk of injury. 

Studies performed in Sweden and Japan conclude that many robot-related accidents occur outside of normal operating conditions—usually during programming, maintenance, repair, testing, setup or adjustment.  In most instances, work procedures require the operator or maintenance worker to enter the work envelope where unintended operations could result in injuries.  To do this, operators temporarily override perimeter guarding or light curtains, thereby endangering the worker entering the work zone while the machine is operational.  In contrast, a modern safety approach respects the behavior of factory personnel and implements safety solutions that permit safe access to work zones.  This approach enables significant improvements in manufacturing productivity and expands the market for newer robotics. 

In recognition of these new safety approaches, the Robotics Industry Association is revising the ANSI/RIA R15.06 standard to recognize “collaborative robotic systems.”  To do this, the standard is adopting the safety standards developed for ISO 10218 in which risk assessment is graded on performance levels as outlined in the ISO 13849 machine safety standard. 

Collaborative robot capabilities have been modified significantly to comply with the safety standards that address environments in which robots work in conjunction with humans. Speed, load, and task type for these new robots are quite different from traditional iterations.  Lower speeds and lighter loads reduce forces to tolerable limits.  In addition, bump sensors or vision sensors have been incorporated to avoid or mitigate collisions.

With these new advances, it is time for manufacturers to adopt these safety guidelines because robots now offer more than specific, repetitive tasks.  Manufacturers should more closely evaluate robotics applications that can benefit from dynamic decision-making and autonomous behavior. 

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