The biggest challenge of the COBOT project was not only implementing the required process technology requirements, but the safety technology requirements as well. The automated robot application needed to be usable without any protective enclosure, safety fence or light barrier. The collaborative robot needed to be able to execute screw fitting of nine screws in a headlamp lighting strip in a maximum cycle time of just 70 seconds – in accordance with the safety guidelines for human-robot collaboration. The lighting strip is inserted manually into the provided mount by the operator. After fixing the component in place, the operator presses a button to deliver the work release to the robot. While the operator manually positions additional components, the robot approaches the positions of the different screw holes, and automatically screws in the screws.

Operator safety is key
The biggest challenge in programming the COBOT was ensuring safety for operating personnel. “We carefully analyzed and evaluated potential hazards, then implemented these in a safety concept, for instance with a movable screw jack. If the robot’s or screw jack’s sensors, for instance, detect a resistance or collision during the movement, the sensors transmit this information to the robot’s safety and PLC controller. Then the COBOT stops or takes evasive action immediately. A normal industrial robot can’t do that” says Christian Blaumauer, ZKW COBOT Project Manager. Disengaging the spindle mouthpiece takes only a very small amount of force. The system can immediately detect and prevent any possible collisions, for instance between the screw jack, fingers, and the lighting strip. This development has been submitted to the European Patent Office. The ZKW employee working with the COBOT confirms that the system is usable and practical: “I don’t have to monitor the COBOT’s work, I trust the robot completely. We are a good team, and I don’t have to do the tiring work of screwing in screws by hand.”

Efficient & traceable
The advantages of human-robot collaboration outweigh the investment costs. Human-robot collaboration helps improve the economic efficiency of manufacturing. Robots and operators work in parallel. In addition, a higher degree of automation helps ensure better quality. The integrated scanner records the serial number of each component. This makes it easy to trace faulty batches. “In the future, the COBOT can be used to support other work steps in production, for instance in component handling” says Oliver Schubert.