Power-sensitive, dynamic, energy-efficient and with a range of applications - these are the characteristics of the new robotic gripper from the Fraunhofer Institute for Mechatronic System Design IEM. It can move fragile objects from one production step to another without damaging them. The robotic gripper is specially designed for the food industry, where careful handling of fragile products helps prevent wastage. The electric drive eliminates the need for expensive pneumatics.
Automatically transporting, sorting and packaging fragile food products is not easy. The robot has to handle the products quickly and dynamically. Be it eggs, meringues, meatballs, biscuits, chocolates, doughnuts or anything else, without damaging them with pressure marks or other bumps. Researchers at the Fraunhofer IEM in Paderborn developed a robotic gripper for use in the food industry. This was done as part of a project funded by the state of North Rhine-Westphalia. Fraunhofer presented the robotic gripper at Hannover Messe 2023 as part of a cobot workstation, which moves chocolate-covered marshmallows without damaging their fragile coating.
Two, three or four fingers
The gripper system can be set up with two, three or four fingers and can be adapted for different tasks and purposes. That means it can also be used for automated handling of other fragile products such as glassware. "The fingers have a plastic, soft and flexible coating. As a result, they maintain a delicate grip on fragile materials and do not damage them.
Dynamic gripper
"The robotic gripper is also highly dynamic and is easy to integrate into production processes. It maintains the required balance between speed and sensitivity at all times," says Dr Christian Henke. He is head of the scientific automation department at Fraunhofer IEM. The precise and dynamic control technology enables targeted finger movements and complex product control. Sensors integrated in the fingers determine the required amount of pressure.
Electric
The special advantage of the system: the gripper is operated electrically rather than pneumatically. Thus, it operates energy-efficiently and uses existing power connections. "Until now, gripper systems were pneumatically driven. That costs a lot of energy. Generating air under pressure is less efficient, even less because of frequent leaks in the pipes," explains the engineer.
Human-robot cooperation
The action radius of the system can be extended with a linear axis, i.e. a horizontal path. For this purpose, the robot gripper is mounted on a vertical lifting column, which is attached to the linear axis. The gripper is suitable for safe cooperation between human and robot thanks to its sensor-based environment recognition system. However, this does not apply to the axes (both the linear axis and the lifting column).
No safety barriers required
To make the entire workspace collaborative, researchers developed a 360-degree environment recognition system. This system monitors the full length and height of the axes. It can be integrated into the base of the linear axis. "This multisensor system includes remote and thermographic sensors. This allows the entire cobot and axis structure to work together. This means companies do not need to install safety barriers," says Henke. "If required, the gripper can be combined with the linear axis and the multi-sensor system. It can also be used alone." Initial tests have been successful and the Fraunhofer IEM team is now looking for partners to bring the robotic gripper to market.
Image: Fraunhofer IEM researches intelligent gripping systems (Photo: Fraunhofer IEM/Wolfram Schroll)
Also read: Research shows rise of cobots among SMEs
