FEATURE WORKPLACE SAFETY
BRINGING DOWN THE BARRIERS U
The introduction of collaborative robots is bringing down the barriers between robots and humans. However, safety should still be a primary consideration
ntil recently many industrial robots needed to be isolated behind a
protective cage. However collaborative robots are changing this, enabling people to work alongside robots. The new green liveried FANUC CR-35iA, for example, is a totally cage-free robot, designed for tasks such as heavy workpiece transfer (up to 35kg) and parts assembly. It features a soft surface to reduce impact force and to prevent human operators being pinched. Certified to meet the requirements of international standard ISO 10218-1, if the robot comes into contact with a human co-worker or any object with a certain force, it stops or retracts immediately. Although this new breed of collaborative robots address many robotic safety standards they have not eliminated the need for comprehensive workplace risk assessments.
EMBEDDING GREATER CONTROL “Advances in software control technology and integrated safety mean that it is now possible to impose set limits on how fast a robot works and the operational areas it can and cannot enter. It can be programmed to slow down as it approaches a hazard, rather than coming to an abrupt standstill, and presence-sensing detection can be introduced,” said Steve Capon, technical manager at FANUC UK. These technology
Collaborative robots are bringing down the barriers
or mechanical devices to supply this functionality.” FANUC recently demonstrated an example of a fenceless robot cell in collaboration with Rockwell Automation. In this showcase, Rockwell safety laser scanners were installed close to floor scanning horizontally for any approach to the system. As an intrusion got closer, the scanners informed the robot system to operate slower. Additional mini scanners were concealed under the FANUC robot system mounting, providing an invisible shield and initiating the robot to stop when the box of light is encroached.
“One of the key advantages of being
able to embed more of the safety-related functions into the robot controller is that you can design out the various safety hazards...”
developments are enabling manufacturers to think more creatively around how automation equipment is deployed and how companies can boost production efficiencies while also saving space in valuable commercial real estate. “Safety risks vary depending on the selected robot and application,” emphasised Capon. “One of the key advantages of being able to embed more of the safety- related functions into the robot controller is that you can design out the various safety hazards while also eliminating the need for external fixtures
14 SUMMER 2016 | INDUSTRIAL COMPLIANCE
SETTING YOUR SAFE LIMITS Many of these developments – such as FANUCs Dual Check Safety (DCS) Position & Speed Check solutions – were initiated in the automotive sector on CNC robots. However, the trend for built in logic and safety motion is now spilling into other markets, including packaging and palletising.
In addition to meeting the safety requirements for electronic control systems, DCS Speed and Position Check offers benefits to
applications where the travel of the robot needs to be restricted due to floor space or process limits that are less than the full reach of the robot. Restricting the robot motion in Cartesian space means that the robot can be restrained to an exactly designated safe area in which it works; something that is not possible with systems that limit robot motion externally using limit switches. The software works across the whole robot model – not just a single point. Position Check, for example, can identify multiple areas of the robot, including any attached end effectors. The safe zones
around the robot arm and its end effector can be modelled within the software, using geometric shapes of up to eight vertical lines each. These areas can be adapted – enabled and disabled to change the areas that the robot is not allowed to enter – depending on the task it is undertaking and the changing conditions within the defined area. “This is a useful feature for applications that require an operator to load parts into a fixture, for example,” said Capon. “An operator can safely walk into the area because the robot will stop the task it is performing. When the operator leaves the defined area, the robot is able to continue with its task.” The Speed Check functionality makes it
possible to define the maximum speed that the robot can travel during normal operation. Speed can also be changed in reaction to a defined event, in addition to ensuring that the robot holds a position when necessary. “This can be used for zero speed monitoring,” explains Capon. “Often, there are rotary fixtures within a cell which must not move while the operator is undertaking a loading procedure. The Speed Check functionality allows the speed of the fixture to be monitored, and ensures it remains motionless when required.” Ultimately, the onus on safety still rests
with humans. Even with all these technology advances and comprehensive workforce training you cannot risk becoming risk complacent. Every intentional and unintentional scenario when interacting with robots needs to be factored in when conducting regular risk assessments. With safety, getting it mostly right isn’t an option!
FANUC UK
www.fanuc.eu T: 02476 518 449
/ INDUST RAL COMPA RI CE
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