Humans should work together with industrial robots, is that possible?

Collaboration between humans and robots in shared work areas is more in demand than ever. The trend towards robot cells without protective fences and the smallest possible size continues in industry. At the same time, the robot should be integrated into manual work steps as simply as possible and without compromise. Creative ideas and practicable solutions are necessary to meet this increasing demand for human-robot collaboration. The advantages of a classic industrial robot cell, such as speed, accuracy, high productivity and durability, should by no means be neglected. The robot’s payload also plays an important part, but is very limited in existing human-robot collaborations.

Collaborative robots cannot serve these high demands of industry, as they work at significantly lower speeds and with lower payloads than industrial robots. The limits also quickly become apparent in the area of connectivity and integration options in existing systems. For this reason, KUKA, together with SICK and Blue Danube Robotics, is now offering a complete solution that combines both maximum productivity and the latest safety standards for collaborative applications. First and foremost, safe collaboration between robots and humans is guaranteed, even with payloads of several 100 kg. Smooth interaction between all components is made possible by the robot controller and the KUKA.SafeOperation technology package.

The sBot_Speed CIP system variant for KUKA from SICK combines a microScan3 with the Flexi Soft safety controller and the EFI-pro gateway. The already verified safety system enables the safe simultaneous monitoring of several protective fields and also detects people who may step behind the protected area. The robot-specific settings and communication parameters are already pre-configured and can be integrated quickly and safely into the KUKA KR C4 robot controller thanks to EtherNet/IP™ CIP Safety™. This saves valuable time in project planning and evaluating the safety concept.

The microScan3 permanently monitors the robot cell and divides the working area into three zones (see figure). If there is no person in the danger zone (green zone), the robot can reach linear speeds of up to 2 m/s. A comparable collaborative robot operates at a maximum speed of 1 m/s. If a person approaches the robot and is therefore in the orange area, the speed of the robot is reduced so that it meets the requirements of the risk assessment according to ISO TS15066. The orange area serves as a detection area and is used as a buffer zone so that the robot can reduce to the required speed. Entering the yellow area now activates the safe monitoring of this reduced speed. If this speed is exceeded, the robot stops with a safety stop 1 (near-track EMERGENCY STOP) according to EN 60204. Once the orange and yellow areas of the laser scanner are vacated again and there is no person in the danger zone, the robot accelerates to the programmed speed independently.

The SafeOperation technology package is the interface between the safety components. It processes the signals from the safety interface, monitors the robot movement and offers other safety features. These include defining safe monitoring areas, the safe monitoring of speeds and regular adjustment referencing. With these additional features, the position of the tool can be monitored during the entire operation and the robot can be stopped safely in case of malfunction. In order to be able to stop the robot movements quickly enough in the event of malfunctions or violations of spatial limits, the brakes must be guaranteed to be in perfect condition. This is checked using an automatic brake test. This involves cyclically checking whether the motors’ braking torques are high enough and ensure the safe stopping of the robot if necessary.

The KUKA.Handguiding optional package is used to ensure that the operation between the industrial robot and human is also as practical and efficient as possible. The control package enables wireless hand-guiding of industrial robots in an extremely user-friendly way. The robot is controlled by a 6D mouse mounted on the robot, which makes it possible to program movement points and record movement sequences. This allows the KUKA industrial robot to be moved in a simple and intuitive manner. The use of this package does not require any training or time-consuming employee induction.

The communication between the components must also be in synch to ensure smooth operation. The SICK safety system (microScan3 safety laser scanner + Flexi Soft safety controller) is connected to the robot controller by a safe fieldbus such as EtherCat/FSoE, EtherNet/IP/CIP Safety or PROFINET/PROFIsafe. The AIRSKIN is connected to the safety controller’s safety inputs by 2 channels.

Together with the partners Blue Danube Robotics and SICK, a careful selection of the components was made to enable the simplest possible integration with the highest safety standard. The test setup took place at the KUKA Application Center in Steyregg, where the interaction of the components was thoroughly checked and tested. This test setup is still available for customers and can be visited at any time if interested (by appointment).