In order to quickly and easily implement collaborative bot applications, Coboworx and Fraunhofer IWU from Dresden are looking to accept virtual bot security by default commissioning.
In times of diminishing contract sizes, shorter product life cycles and volatile markets, jobs in which humans and robots can work flexibly side by side are especially in focus. However, this close cooperation between human and cobot also leads to high demand for safety equipment for cobot workstation. In addition to the torque-force sensors built into the robot cups themselves, environmental monitoring optical sensors are used as a precaution.
Excessive travel is critical
To do this, the kobot, including the tool and track movement, must be measured and tested on site. This is the only way to make sure that the kobot does not pose any danger to humans. Bypassing the kubot is especially important for obtaining certification. This increased travel corresponds to the distance traveled after the emergency stop signal was triggered.
Thus, the road to the final cobot implementation is time consuming and requires a lot of knowledge. According to the current technical condition, the measurement can only be done after setting up the specific application. As a result, cobot applications are often practically uneconomical for small batch sizes.
who – which Fraunhofer IWU Therefore, together with start-up Coboworx, they are currently developing an innovative method to expedite and simplify safety approval. The concrete application scenario is Kobot taking on the task of pick and place and is secured with laser line scanners and radar sensors for environmental monitoring.
digital twin from kubot
In order to be able to get the cobot up and running as quickly as possible, Dresden researchers are using a digital twin for the entire cobot app. The kobot simulation model aims to map the movement behavior of a real robot with special accuracy. This means that security checks can be run virtually on a computer model without the cobot app having a real build.
To do this, the Virtualization Commissioning (VIBN) methods must be adapted to Cobot’s safety requirements. Because: Existing VIBN models visualize reality with sufficient accuracy to examine control functions, but the detailed movement behavior of the robot piece, including overtaking after an emergency stop, is also critical to a safety check.
In order to enable virtual security approvals, researchers in the Interdisciplinary Department of Physical Cyber Production Systems at Fraunhofer IWU are developing a cobot model with a high level of detail for virtual commissioning. They also implement additional algorithms to more realistically set the behavior of the movement.
detailed model
In addition to the engine control devices, a large number of mechanical and dynamic influence factors are also taken into account in the model. As a result, the digital twin of the Cobot not only moves without delay at the directions of the real console, but also with sufficient accuracy to assess safety.
During the simulation, virtual sensors, such as at the edge of the robot or at the tip of the tool, accurately document the movement of the virtual bot. From this, position, velocity, acceleration and also acceleration can be calculated. So true measurement of excessive travel should not be necessary in the future.
Using the digital cobot twins from Fraunhofer IWU and Coboworx, cobot applications must be testable at the planning stage or in parallel with ongoing operations. Complex measurements and costly downtime can be reduced in this way. A faster and more economical way to secure cobot workplaces opening.
Fraunhofer IWU
www.iwu.fraunhofer.de
www.kognitive-produktion.de
Coboworx GmbH
Virtual commissioning and digital twin
With VIBN virtual operation, real production systems in operation can be controlled on the digital twin. The VIBN digital twin includes a model of all machine components including actuators and sensors. These are visualized in three dimensions and the moving components are provided with joints. For example, a sequentially animated robot is created from a solid CAD model.
The prerequisite for VIBN is the computation of the simulation model in real time for deterministic control, that is, with a response time of 1 millisecond. Real controllers can be connected to the computer on which the digital twin is running for HiLS via shared field buses. The robot control project, which was planned as usual, starts on the controllers, which then communicate with the virtual machines in the simulation model instead of the real ones.
The cot on the computer screen moves without delay based on instructions from the real console. Existing VIBN models depict reality with sufficient accuracy to verify control functions. However, for the safety check, the detailed movement behavior of the robot is also crucial, as this largely determines overtaking after an emergency stop.
for authors
Philip Gerck, Research Associate, Fraunhofer IWU
Christer Schenke, Group Leader based on the development model for self-improving production systems, Fraunhofer IWU
Olaf Geirels, Managing Director of coboworx GmbH
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