Dynamic risk assessment and active response strategy for industrial human-robot collaboration

To enhance flexibility and sustainability, human-robot collaboration is becoming a major feature of next-generation robots. The safety assessment strategy is the first and crucial issue that needs to be considered due to the removal of the safety barrier. This paper determined the set of safety indicators and established an assessment model based on the latest safety-related ISO standards and manufacturing conditions. A dynamic modified SSM (speed and separation monitoring) method is presented for ensuring the safety of human-robot collaboration while maintaining productivity as high as possible. A prototype system including dynamic risk assessment and safe motion control is developed based on the virtual model of the robot and human skeleton point data from the vision sensor. The real-time risk status of the working robot can be known and the risk field around the robot which is visualized in an augmented reality environment so as to ensure safe human-robot collaboration. This system is experimentally validated on a human-robot collaboration cell using an industrial robot with six degrees of freedom.