Transferproject T2

Control of Uncertainty by use of a highly integrated active suspension system

The purpose of this transfer project was to develop the active air spring damper (aLFD) into a car-suitable prototype and implement and test it in a luxury-class sedan and to master the uncertainty arising during the transition from the component to the system.


Experimentally, the four-quadrant operation in the force-path diagram, which is characteristic of an active suspension strut, has been successfully demonstrated with the aLFD. Long-term tests showed that the bellows can withstand the higher stresses caused by the employment of the active rolling piston. Thus, the concept of the active change in the supporting surface of the air spring by way of an adjustment of the rolling piston diameter is in principle suitable for use in a series-production vehicle. The reduction in the energy consumption of the active shock absorber system is a prerequisite for use in the vehicle. Therefore, in a concept study, a hydrostatic system with minimum energy consumption was designed using the TOR method developed in SFB 805. However, the theoretical and experimental investigation of the first prototype, as well as an estimation of the potential for innovation, showed that the use of the actuator and transmission concept used – hydraulic swivel motor with mechanical cam transmission – is not useful. The reason for this is the high weight, the required space and the low mechanical efficiency of the transmission of approximately 60%. For this reason, in consultation with the industrial partner, it was decided to re-conceptualize the aLFD what is being continued in subproject C4.

The ended subproject T2 has been able to lay the foundations for the design of the active change in the rolling piston diameter as well as to define the system requirements of the aLFD for successful integration into a standard vehicle. Thus, it forms a basis for the subproject C4, that can be based directly on the results of T2 in the third delivery period. The developed method for the reduction of energy consumption is used as application examples within the framework of the TOR course at the Chair of Fluid Systems.

[1] Dörig, B.; Ederer, T.; Hedrich, P.; Lorenz, U.; Pelz, P. F.; Pöttgen, P.: Technical Operations Research (TOR) Exemplified by a Hydrostatic Power Transmission System, Vol. 1, 152-161, Aachen, 24-26.03. 2014.

[2] Hedrich, P.; Cloos, F. J.; Würtenberger, J.; Pelz, P. F.: Comparison of a New Passive and Active Technology for Vibration Reduction of a Vehicle Under Uncertain Load, Applied Mechanics and Materials, Vol. 807, pp. 57-66, 2015.

[3] Hedrich, P.; Pelz, P. F.; Nakhjiri, M.; Fäth, S., Dehlwes, S.: Luftdämpfung als zukunftsweisende Technologie im Nutzfahrzeugbereich – Optimale Auslegung eines Luftfederdämpfers. VDI-Berichte 2261, pp. 145-153, 2015.

[4] Bedarff, T.: Grundlagen der Entwicklung und Untersuchung einer aktiven Luftfeder für Personenkraftwagen, Dissertation, TU Darmstadt, eingereicht am 26.01.2016.

[5] Utz, M.; Hedrich, P.; Pelz, P. F.: Computing an Operating Strategy for an Active Body Control with Dynamic Programming in the Automotive Application, Conference Proceedings ECCOMAS 2016.

Subproject Managers

Photo Name Contact
Prof. Dr.-Ing. Peter Pelz