Functional Safety and its Application to Automated Industrial Cobots
Standards developments related to HRC
The key international C-type standards covering Industrial Robots, EN ISO 10218-1 and EN ISO 10218-2, were revised in 2016. These provide updated safety guidance covering HRC applications detailing four techniques for collaborative operation (Table 2). However, despite listing some general safety requirements for collaborative robots, market feedback was that the standard did not provide enough engineering guidance. To address this, ISO/TS 15066 was released to supplement the requirements of EN ISO 10218 1 / 2 by providing hard data, such as a list of maximum force and pressure levels for each part of the human body[1]. This data can be used to establish a set of force/pressure thresholds that the robot should not exceed and is intended to guide robot design and integration. ISO/TS 15066 also provides maximum allowable robot power speed design criteria and a deeper explanation of collaboration techniques to aid in the categorisation of a system as collaborative.
EN ISO 10218 -1/2 make appropriate reference to B-type standards when defining safety standards for HRC systems. One example is the safety-rated monitored stop, IEC 60204-1, that defines 3 categories of stop:
ISO 13850 however limits the selection of stop category to Category 0 or 1 and excludes Category 2
Table 2: HRC Safety Criteria defined in EN ISO 10218-1.
The key international C-type standards covering Industrial Robots, EN ISO 10218-1 and EN ISO 10218-2, were revised in 2016. These provide updated safety guidance covering HRC applications detailing four techniques for collaborative operation (Table 2). However, despite listing some general safety requirements for collaborative robots, market feedback was that the standard did not provide enough engineering guidance. To address this, ISO/TS 15066 was released to supplement the requirements of EN ISO 10218 1 / 2 by providing hard data, such as a list of maximum force and pressure levels for each part of the human body[1]. This data can be used to establish a set of force/pressure thresholds that the robot should not exceed and is intended to guide robot design and integration. ISO/TS 15066 also provides maximum allowable robot power speed design criteria and a deeper explanation of collaboration techniques to aid in the categorisation of a system as collaborative.
EN ISO 10218 -1/2 make appropriate reference to B-type standards when defining safety standards for HRC systems. One example is the safety-rated monitored stop, IEC 60204-1, that defines 3 categories of stop:
- Category 0: stopping by immediate removal of power to the machine actuators (i.e. an uncontrolled stop)
- Category 1: a controlled stop with power available to the machine actuators to achieve the stop and then removal of power when the stop is achieved
- Category 2: a controlled stop with power left available to the machine actuators.
ISO 13850 however limits the selection of stop category to Category 0 or 1 and excludes Category 2
| ISO 10218-1 clause | Safety feature | Typical application | Separation distance | Main risk reduction |
| 5.10.2 | Safety-rated monitored stop | Loading/unloading | Small/zero | No motion in presence of human |
| 5.10.3 | Hand guiding | Assembling, filling | Small/zero | Motion only by direct operator input |
| 5.10.4 | Speed and separation monitoring | Handling, inspection | Safety-rated monitored speed/distance | Prevention of contact |
| 5.10.5 | Power and force limiting | Collaborative assembly, loading | Small/zero | Inherent design, or control, to prevent excessive force |
Table 2: HRC Safety Criteria defined in EN ISO 10218-1.
[1] Derived from a study conducted by the University of Mainz in Germany.
Read full article
Hide full article
Discussion (0 comments)