Robot supports workers precisely and reliably
Bietigheim-Bissingen, March 2017 – As a supplier of turnkey plants for automated gluing processes, Dürr develops robot cells with human-robot collaboration (HRC) for the automotive industry. In these cells, humans and robots work side by side in final assembly operations without any protective systems separating them. HRC concepts help to improve the quality of the gluing process when items such as roof fins and fuel tanks are fitted to the vehicle body, while also saving time and reducing unit costs. The compact design of the robot cell saves space and alleviates the physical demands placed on the workers. For its HRC solutions, Dürr uses sensitive LBR iiwa lightweight robots supplied by KUKA.
When gluing the roof fin, for example for a GPS antenna, the worker manually places the workpiece into the robot's gripper, which holds it pneumatically and guides it to the adhesive nozzle on the application tower. The robot moves the fin slowly from below to the adhesive nozzle. "If the robot encounters an obstacle, it retracts a little due to its ability to detect a collision and starts the action over again," explains Dieter Ahlborn, Head of Gluing Final Assembly at Dürr Systems AG. Only after three failed attempts will the LBR iiwa return to its starting position.
Otherwise, the gluing process will begin and the glue bead is then carefully applied while the robot moves along a specified path. When this operation is complete, the worker removes the fin at the starting point and installs it onto the vehicle.
Strict safety regulations
HRC solutions have to fulfill the strictest safety requirements. For example, the robot is placed in such a position as to minimize direct contact with humans. Furthermore, the robot must stop within milliseconds if any contact is registered. The concept for the gluing cells is designed in such a way that the robot always operates below the worker's head and chest area. The application system, consisting of a lightweight applicator and the lightweight robot, is designed with large surface areas and is soft and rounded to ensure that only low forces are generated when contact is made with the robot.
HRC systems are a major topic in the automotive industry. Dürr supplies the plant technology for new human-robot collaboration completely from a single source. "We have already sold ten units for gluing operations," Dieter Ahlborn reveals. The first unit with an application for gluing a fuel tank was put into operation by the first customer in March 2016. You can read more about this field of application here.