A probe was to be pulled underground through channels with a length of up to 300 meters. The movement profile was to pull a certain distance, then stand still, then pull a certain distance again. This automatic rope pulley was only to be designed as a pulling station and not as a rope winding pulley due to the limited installation space at the end of the duct. The maximum force should be adjustable and the position, speed and required force should be readable in real time.

As the rope could not be rolled onto this winch, which was only responsible for hauling, the rope could slip on the shaft. Furthermore, requirements due to the ambient conditions had to be taken into account.

A special motor with an integrated winch was used. This fitted into the installation space and the customer was able to save costs for the overall system, as the design was simplified and fewer parts such as a timing belt were required. However, the motor had to be specially wound for 48 V. We were able to organize prototypes for the customer quickly.

The slipping of the rope on the winch was solved by installing an additional encoder in the system, which measured the travel of the rope. The commutation of the motor (FOC) continued to run via the encoder integrated in the motor, but in position control mode the external encoder was used as the actual position to compensate for the slippage.


Our X1 controller was used as motor controller with adapted firmware. We were happy to support the TALPA team with the mechanical integration of the drive technology.

The data was streamed to a control PC at 50 Hz, helping our client to obtain important data points regarding rope forces. By automating the previously manual process, efficiency on the construction site as well as the data quality of his measurements could be increased.