How sensor fusion enables AMRs to maneuver around factory floors efficiently
Type 1
Requirement
2
3
4
Safety performance in accordance with IEC 62061 and/or ISO 13849-1
SIL 1 and/ or PL c
SIL 2 and/ or PL d
SIL 3 and/ or PL e
N/A
SIL = safety integrity level; PL = performance level
Table 1: Safety requirements for ESPE by type specified in IEC 61496. (Table source: Analog Devices)
and mapping. It is the process of continuously updating the map of an area for any changes while keeping track of the robot's location. Sensor fusion is needed to support SLAM and enable the safe operation of AMRs. Not all sensors work equally well under all operating circumstances, and different sensor technologies produce various data types. AI can be used in sensor fusion systems to combine information about the local operating environment (is it hazy or smoky, humid, how bright is the ambient light, etc.) and enable a more meaningful result by combining the outputs of different sensor technologies. Sensor elements can be categorized by function as well as technology. Examples of sensor fusion functions in AMRs include (Figure 1): ■ Distance sensors like encoders on wheels and inertial
IEC 62998 is newer and can often be a better choice since it includes guidance on implementing sensor fusion, using artificial intelligence (AI) in safety systems, and using sensors mounted on moving platforms outside the coverage of IEC 61496. R15.08 Part 3, when it's released, may make the R15.08 series the best since it will add safety requirements for users of AMR systems and AMR applications. Likely topics may include sensor fusion and more extensive AMR stability testing and validation. Sensor fusion functions Mapping the facility is an essential aspect of AMR commissioning. But it's not a one-and-done activity. It's also part of an ongoing process called simultaneous localization and mapping (SLAM), sometimes called synchronized localization
Good, better, best AMR designers have a range of safety standards to consider, starting with general-purpose functional safety standards like IEC 61508, ISO 13849, and IEC 62061. There are also more specific safety standards related to sensing human presence, such as IEC 61496, IEC 62998, and the ANSI/A3 R15.08 series of standards. IEC 61496 offers guidance for several sensor types. It refers to IEC 62061, which specifies requirements and makes recommendations for the design, integration, and validation of electrosensitive protective equipment (ESPE) for machines, including safety integrity levels (SILs), and ISO 13849 that covers safety of machinery and safety- related parts of control systems including safety performance levels (PLs) (Table 1).
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