Are collaborative robots safe?

Collaborative robots (cobots) market is supposed to increase rapidly. Although cobots are safer than their ancestors, industrial robots, there are some safety issues. The risk assessment for cobots is difficult since the cobots are working beside humans. In most of the applications the cobots can be safe. Sharp tools or objects and risk of impact to head are excluded from the common applications due to their risks. The common idea is to apply power and force limitation to ensure safe performance of cobots. The speed of the robot has huge effect on the impact force. Speed reduction with adequate safety controls can decrease the impact force to acceptable level in most of the applications. If there are severe risks in the robot cell, then it is possible to apply adequate separation distance between human and robot or safety-rated monitored stop to ensure safety and relatively close vicinity between human and the robot. One issue is that the stopping performance is complex and currently it is difficult to predict. Quite often, the validation requires impact force/pressure measurements or impact modelling.