application lie on the continuum of collaboration (see Figure 1)? The closer the interaction between the cobot and people, the more safeguarding is needed. There are more details to consider. Some of them include:
Safety contact mats
Conclusion
Safety contact mats have two conductive plates separated by a rasterized insulating layer and can be used alone or in combination with other types of sensors. If a person steps on the mat, the top conductive plate is depressed and contacts the lower plate, triggering an alert signal (Figure 5). The exterior of the mats is a polyurethane material that's slip-resistant and impervious to water, dirt, and oil. The SENTIR mat model 1602-5533 from ASO Safety Solutions can connect up to 10 mats in series to a single monitoring unit for a maximum coverage of 10 m 2 .
Cobot safety is complex. It begins with defining the collaborative workspace within the safeguarded space and requires a risk assessment of the collaborative operation. Standards like ISO/ TS 15066 and the ISO 10218 series are important and provide recommendations and guidelines. Cobots include basic safety features like collision detection systems, force feedback, elastic actuators, and low-inertia servo motors. Depending on the specifics of the collaborative application, additional safety devices like proximity sensors, light curtains, and safety contact mats may be needed.
■ Each location needs to undergo a detailed risk assessment to see if the
cobot has been moved from workstation to workstation. Even if they appear to be the same, small variations can make a difference in safety. ■ If other machines are in the collaborative workspace, do they need to be linked to the shutdown system or the safety slowdown for the cobot? ■ This article has focused on safety-related hardware, but for networked systems that are increasingly common, cybersecurity is an important consideration to prevent interference with cobot operation or the safety systems.
Safety is in the details
There is no single formula that guarantees safety. Every collaborative application is different and needs to be handled based on its unique characteristics and needs. A key factor is: where does the
Figure 5: When stepped on, the safety mat's top and bottom conductive layers make contact, triggering an alert signal. (Image source: ASO Safety Solutions)
we get technical
19
Powered by FlippingBook