Improved safety for workers near robots

Louise Smyth

The ability for robots and people to work in closer proximity holds the promise of ever-more flexible production in automated manufacture. But, while identifying more cooperative human robot applications may be easy, integrating equally simple safety solutions that protect workers without losing productivity has proved more challenging.

Sick has responded with a simple to implement and regulatory-compliant safety protection system, Sick Safe Robotics Area Protection, enabling unrestricted safe access to fenceless robots.
The solution is designed for both machine builders and for production teams looking to boost the productivity of their existing robots or automate new processes such as machine tending, pick and place assembly and materials loading and unloading.
Sick Safe Robotics Area Protection is an easily-integrated safety system for cooperative human robot applications that satisfies Performance Level PLd/SIL2 in accordance with EN ISO 13849-1/EN62061. The robot standards EN ISO 10218-1 and EN ISO 10218-2 state that safety-related parts of control systems should be designed so that they achieve PLd/SIL2 unless the results of the risk assessment determine otherwise.
The turnkey solution integrates a Sick safety laser scanner with a Sick Flexi Soft controller to enable dynamic protection of the monitored area. The result is unrestricted access to the robot, for example to allow someone to inspect the operation of the robot or machinery, or to insert or remove workpieces. 
The monitored area is configured with two field sets, each with a non-safe warning field and a safety-rated protective field. The field sets are programmed to be selected dynamically, so that the robot can be slowed to a safe speed as a person enters the warning field and approaches the robot but can still be stopped safely when the protective field is infringed.
If the risk assessment allows it, when the person leaves the hazardous area, sequence monitoring can be implemented, so that the robot is first started up at a reduced speed and then returns to its original working speed once all the warning and protective fields are free.
As a result of this dynamic field switching, stop times are reduced and the operator’s work flow is uninterrupted. However, the worker is still fully protected against hazardous movements in proximity of the robot’s working range. Minimising stops also reduces machinery wear, leading to less maintenance and improving the total cost of ownership.