Closed-loop control of unsteady flows around bluff bodies including lateral vehicle dynamics

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Long-term goals of this project are the improvement of lateral dynamics and a lower fuel consumption of vehicles exposed to unsteady flow conditions. During the first phase of the project, we developed and implemented closed-loop active flow control methods which allow for an efficient reduction of the drag coefficient and an enhancement of the lateral vehicle response to unsteady cross-winds. The goals set for the first phase, regarding flow characterization during gusts, simulation of the lateral vehicle dynamics by using a movable wind-tunnel model, development of a suitable actuation concept, linear parameter-varying modeling of the aerodynamic response to the actuation and synthesis of suitable controllers have been already achieved.During the second phase we plan to also indentify models for the transient aerodynamics due to cross-wind gusts as well as for the effect of the vehicles motion on the flow. These models can be used to increase the controllers bandwidth regarding the suppression of unsteady forces during gusts in order to further improve driving security and comfort. Another goal is the development of a systematic approach to incorporate LPV-models of the lateral vehicle dynamics and the driver behavior into the control synthesis procedure. Furthermore, we plan to extend the control structure by using dynamic reference trajectories to further reduce the vehicles energy consumption. In order to do so, drag reduction and actuation effort must be evaluated in real-time in a suitable way. This involves abandoning measurements which are only accessible in wind-tunnel setups such as the yaw moment. Instead we plan to use sensor information which is available on-road. Finally, an extrapolation of the experimental results to the real-world scale will be done with respect to power savings and increased safety.