FlowBot gantry for hydrodynamic research

Researchers use these results, among other things, to optimize the design of cars, ships, and airplanes. Until now, wind tunnels have often been used in fluid dynamics to determine the forces acting on moving objects. A drawback of this method is that measurements are taken at constant flow velocities. In practice, however, cars, airplanes, and boats always move at varying speeds and accelerations. To advance our understanding of hydrodynamics, it is therefore desirable to conduct fundamental research on objects moving at non-constant speeds and with self-determined motion. That is exactly what the FlowBot makes possible. It is designed to move objects through a tall, transparent water tank measuring 5 x 2 x 2 meters while accurately collecting data and taking measurements of the flow and forces.

Impulsive flows

“Research into impulsive flows is relatively new,” says Gertjan Mulder, project leader for the FlowBot within the Fluid Mechanics section. “We already had a small, simple setup for this, but we wanted to be able to do more in terms of speed, acceleration, and jerk. For this research, it’s important to be able to follow precise paths. This is possible with the new FlowBot controlled by SINUMERIK. The accuracy of the CNC control is especially important because multiple axis systems must follow each other precisely.”

Ph.D. candidate Jesse Reijtenbagh is conducting the first tests with the FlowBot for his research. “It does exactly what we want,” he says enthusiastically. “We can move in different directions and easily program the speed and acceleration with precision. Because we can work with multiple axes simultaneously, we can have cameras and lighting follow the object through the water tank. That way, we don’t miss a single detail. The information on forces, positions, and other data is stored in a single file. This helps us establish connections between force and speed. The data quality is excellent, so we don’t need to use filters in signal processing. Thanks to the FlowBot’s high precision, we can, for example, study the perfect wing movements of butterflies and birds. We still have a lot to learn from nature!"

The researchers need to collect a large amount of measurement data in a short period of time: forces acting on the test object, along with velocities, accelerations, and positions. The accuracy of the motion must not be affected by the data collection process. For this reason, all measurement data is collected on an Industrial Edge device. By using a dedicated device, the processor in the SINUMERIK cont roller is not subjected to additional load, and data collection does not affect the control speed. The Industrial Edge works seamlessly with the controller. The data, from both the controller and field components, is stored synchronously and at high frequency and can be retrieved via a secure connection from any location. For analysis, the researchers use the Analyze my Workpiece/Capture application.

Make associations rapidly

Gertjan: “We can easily decide for ourselves when data should and shouldn’t be stored. With the FlowBot, we perform many tests in succession. It isn’t necessary to store data between two measurements. As a result, the Edge collects only useful measurement data. This allows us to easily analyze the data across many different experiments, enabling us to quickly establish correlations between the measured force and the path traveled."

Technical implementation

Marcel de Pagter, project manager at Batenburg JB Systems, describes an interesting and challenging process: “For us, this was the first project using the new SINUMERIK ONE and the first time this control system has been applied to such a complex application. To achieve this end result, we worked closely with the partners involved. During the project, we focused primarily on the software, e-engineering, installation, and implementation of safety-related components.”
With support from us, Batenburg JB Systems made optimal use of the SINUMERIK control system. To keep commissioning time as short as possible, Batenburg JB Systems digitally prepared, simulated, and tested many aspects using the SINUMERIK ONE Digital Twin software.

Currently, the FlowBot features 23 synchronously operating axes controlled by a single SINUMERIK controller. The number of axes will be further expanded in the near future with the addition of two 6-axis robots. “The FlowBot pushes the limits of what is possible with the SINUMERIK control system,” says Frank de Korte. “This wasn’t a standard project for Siemens either, but we were confident from the start that what TU Delft was looking for was possible with the SINUMERIK control system. What has been achieved here cannot be done with any other control system, and we are therefore very proud of it.” Gertjan also describes it as a successful project: “We aimed for the highest accuracy and can measure even more precisely than we had hoped. In addition, despite the FlowBot’s complexity, the operation is intuitive and user-friendly. Thanks to the automatically tracking axes, the FlowBot is also easy to program.”