Functional safety in human-robot collaborations (HRC)
High degree of automation versus flexible production work flows: If humans and machines are to work together in closer proximity while maintaining a safe environment, functional safety will take today’s production systems one step closer to more flexibility. Human-robot collaboration (HRC) looks at how this can be achieved.
There are different forms of automation depending on how humans and machines work together. If the ultimate goal is complete collaboration – where humans and robots share the same workspace and carry out their work at the same time – then it makes sense to develop solutions that employ coexistence or cooperation as initial steps toward this. Doing this requires not only an in-depth understanding of robotics applications, but also expertise in assessing risks and access to the right portfolio of safety solutions:
Application example for collaborationAttaching non-rigid parts in electric motor assembly, for instance. A safely monitored robot at a mobile work station takes assembly groups from the conveyor belt and presents them to the worker in an ergonomic position.
- Risk assessment: The robot’s movements may cause collisions, shearing, and crushing
- Possible protection: Horizontal hazardous area protection with microScan3 Core safety laser scanner. Limiting the Cartesian workspace as well as the robot’s force and torque; monitoring working speed when the protective field is violated. Sheathing the robot tool in an ergonomically shaped housing in order to reduce hazards.
- More productivity: The robot station is mobile and can be used at designated stations as necessary. The robot grabs the right devices from the conveyor belt and is able to carry out subsequent steps on the workbench independently.
Application example for cooperationAt a transfer station, a worker gets pre-assembled modules ready for an assembly robot. The robot grabs one module each time and brings it to the final assembly process.
- Risk assessment: The robot and worker are in the transfer station area at different times. When the worker inserts the modules, a hazard may be posed by the robot moving at high speed.
- Possible protection: S3000 safety laser scanner with 4 simultaneous protective fields, combined with the Flexi Soft safety controller (Sim-4-Safety). Violating protective fields 1, 2, or 3 triggers a reduction in the robot speed, while protective field 4 activates a safety-monitored stop.
- More productivity: Instead of coming to a complete stop, the robot initially continues working as the worker approaches it. Its movement is stopped safely only once the worker is in the direct vicinity of the transfer station (protective field 4). Once protective field 4 has been released, the robot continues working.
Application example for coexistenceInsertion station with rotating table on a welding robot cell, e.g., in the automotive industry.
- Risk assessment: The hazard is posed by the rotating table, since the robot is operating in an area which is fenced off and, therefore, secure.
- Possible protection: A vertically mounted safety light curtain, such as the deTec4 Prime, functions as a primary protective measure to shut down the rotating table. A cascaded, horizontally mounted light curtain monitors whether there are any objects in the safety area (presence detection).
- More productivity: The rotating table is able to restart automatically once the horizontal protective field has been released.