Active damping of torsional vibrations in long, hard-to-reach drive shafts by means of adaptive tracking of dynamic load input functions using the Stribeck curve as an example

• Applicants: Dr.-Ing. Dirk Turschner; Professor Dr.-Ing. Volker Wesling, since 3/2023
• Subject Area: Automation, Mechatronics, Control Systems, Intelligent Technical Systems, Robotics
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 512815763

During operation, drive shafts are subjected to mechanical loads in the form of vibrations due to dynamically acting forces. Experience in the field of deep drilling technology for the development of geothermal fields with long drill pipes shows that torsional vibrations caused by the drill head-induced stick-slip effect in particular contribute significantly to the wear of the shaft components. Since the tribological relationships are also nonlinear, control is often correspondingly complicated. In the course of the research project, these nonlinear friction effects are simulated using two existing friction models. According to the relevant literature, these models have the major disadvantage that the underlying friction parameters are only determined at the beginning of the calculations. However, this assumption does not accurately represent reality as soon as the environmental parameters change, e.g. in the field of deep drilling technology due to changing rock layers. Furthermore, the exact knowledge of these parameters, which are determined within the scope of this project on the basis of the Stribeck curve via the relationship between the frictional torque and the frictional velocity, is often unknown. In the recent past, methods have been developed which do not require the use of friction models by mounting actuators directly on the drive shaft for active vibration damping. Such an approach can only be implemented if the mechanical shaft at hand is spatially and metrologically accessible. Especially in areas such as deep drilling technology, however, these circumstances do not exist. In this research project, the focus is therefore on the following objectives for the development of active damping of torsional vibrations in long drive shafts that are difficult to access: (1.) Development of a generalizable, process-accompanying, mathematical model for the calculation of the dynamic frictional torque (load input function) with adaptive tracking using the Stribeck curve as an example, based on a parameter database to be created; (2.) Design of a self-adjusting state controller architecture for torque control of hard-to-reach drive shafts with multi-mass oscillator behavior for active vibration damping; (3.) Testing of the adaptive controller systems on the test bench to validate the theoretical investigations. The successful completion of this project provides comprehensive knowledge in the area of wear-reducing and cost-efficient operation of drive shafts and, based on the scientific connectivity, allows the results obtained to be tested in an application-oriented manner. With regard to potential areas of application such as the development of geothermal fields or the underground storage of large amounts of (waste) heat, important contributions could be made to current climate policy.

• DFG Programme: Research Grants
• Ehemaliger Antragsteller: Professor Dr.-Ing. Hans-Peter Beck, until 3/2023