FEATURE HAZARDOUS AREAS & SAFETY


ndustrial robots are automated moving devices with multiple axes. Motion paths, sequences and angles can be freely programmed and controlled by sensors. Robots can also be fitted with grippers and other tools, enabling them to manipulate objects and carry out production tasks. Robots are well suited to carry out many different automated tasks and make frequent changes to batches and products. If used without care, robots can be dangerous to humans. Since robots were introduced by the automotive industry back in the 1960s, robot manufacturers such as FANUC have spent effort and money producing models with the best possible safety levels. As robots have become more refined, and applied across more industry sectors, mainly for heavy work, devices are used to monitor a robot’s surroundings, such as vision and force sensors that allow robots to see and feel what is around them. Using smart synthetic skins, scientists are even looking to endow future robots with a human-like sense of touch. In recent years, collaborative robots (Cobots) have emerged: these cage-free robots can work side by side with humans on shared or separate tasks, without the need for safety fencing. Although collaborative robots do not


eliminate the need for workplace risk assessments, the increased adoption of peripheral safety devices is enabling robots and humans to work in close proximity to each other, eradicating the fear of interrupting production or worse, an accident.


Cobots are equipped with force sensing to limit their power and force: in any situation they can feel or detect an abnormal force and stop their motion immediately. Although they still cannot avoid a crash, Cobots can reduce its impact and avoid certain types of incidents, like crushing accidents. Dual Check Safety (DCS) Position/Speed Check features check the speed and positional data of motors with two independent CPUs within the robot controller. These functions can detect any position and speed errors immediately and shut down the motor’s power. Safety data and processes are cross-checked by two CPUs. Self-diagnosis of safety hardware and software is executed periodically to prevent potential failure accumulation. The DCS position speed check software monitors allows safety zones to be quickly


22 MAY 2017 | PROCESS & CONTROL


STAY SAFE WITH YOUR COBOT COLLEAGUE I


Andrew Armstrong, Fanuc UK sales and marketing manager, offers a simple guide to robot safety


and easily designed, ensuring that the robot stays in the designated safe areas, and monitoring the speed of the robot so it operates safely. Another aspect of safety where robots can help is preventing injury to humans through heavy lifting. With health and safety regulations stipulating 25kg as the maximum load an operator may handle, there is a real requirement for robots to handle loads that exceed this limit. FANUC has extended the application


field for collaborative robots with a model that has a higher payload than any other on the market. The human-safe CR-35iA has a 35kg payload, opening up applications that have previously been off limits for both traditional industrial robots and lighter duty collaborative robots, particularly in difficult-to-access areas where conventional assist machinery cannot fit or where a six-axis robot adds dexterity. As collaborative robots are working


alongside humans without any type of shield or guarding, it raises a new level of complexity. In line with ISO 10218 and ISO/TS 15066


standards which relate to the collaborative operation and safety functions, end users or integrators will need to do a complete risk assessment to prove that using a collaborative robot is safe. When doing a risk assessment, while the robot itself may be safe, the entire robotic system has to be considered, including grippers and any other peripheral equipment. Most grippers work on a mechanical, pneumatic, electric or adhesive principle, and also include vacuum suckers. The gripper must cope with the physical and mechanical properties of the object and handle it without leaving any visible marks


The human-safe CR-35iA has a 35kg payload, which is particularly useful, as health & safety regulations stipulate 25kg as the maximum load an operator may handle


or damage. From a safety point of view, grippers can cause pinching or crushing injuries, which should be taken into account in any risk assessment. In 2013, the first safety standards for


collaborative robotics, ANSI/RIA R15.06, were published. More recently, the ISO/TS 15066 standard was published in March 2016. It specifically outlines guidance for and the requirements of collaborative industrial robot systems, such as contact forces and pressures that can be applied to different regions of the body. In order to ensure that humans are not exposed to unacceptable risks when working collaboratively, the current standards describe four separate measures that can be used to provide risk reduction. It is required that at least one of these is


Andrew Armstrong, sales and marketing manager at Fanuc UK


fulfilled, in addition to having visual indication that the robot is in collaborative operation. The four measures are: 1. SAFETY-RATED MONITORED STOP:


when it is detected that a human has entered the collaborative workspace, the robot should stop and remain so until the human leaves the workspace. 2. HAND GUIDING: the human can guide


the robot by hand. 3. SPEED AND SEPARATION MONITORING: the robot must maintain a specified separation distance from the human and operate at a pre-determined speed. 4. POWER AND FORCE LIMITING BY


INHERENT DESIGN OR CONTROL: the power and force of the robot actuators need to be monitored by safety-related control systems to ensure that they are within limits established by a risk assessment.


For lighter duties, the CR-7iA has a payload of 7kg


Fanuc UK www.fanuc.eu


/ PROCESS&CONTROL


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53