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

该项目的长期目标是改善侧向动力学，并降低暴露在非稳定流动条件下的车辆的燃油消耗。在项目的第一阶段，我们开发和实施了闭环主动流量控制方法，这些方法可以有效地降低阻力系数，并增强车辆对非恒定侧风的横向响应。第一阶段的目标已经实现，包括阵风期间的流动特征、利用可移动风洞模型模拟车辆的横向动力学、开发合适的驱动概念、对驱动的气动响应进行线性参数变化建模以及合成合适的控制器。在第二阶段，我们还计划识别侧风引起的瞬时空气动力学以及车辆运动对流动的影响的模型。这些模型可用于增加控制器在阵风期间抑制非定常力的带宽，以进一步提高驾驶的安全性和舒适性。另一个目标是开发一种系统的方法，将横向车辆动力学和驾驶员行为的LPV模型纳入控制综合过程。此外，我们计划通过使用动态参考轨迹来扩展控制结构，以进一步降低车辆的能耗。为此，必须以适当的方式实时评估减阻和驱动效果。这涉及到放弃只有在风洞设置中才能获得的测量结果，例如偏航力矩。取而代之的是，我们计划使用道路上可用的传感器信息。最后，将实验结果外推到真实世界的范围内，以节省电力和提高安全性。

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.