Advanced UAV Aerodynamics, Flight Stability and Control

13 Closed‐loop Active Flow Control for UAVs

Oksana Stalnov

Faculty of Aerospace Engineering, Technion—Israel Institute of Technology, Haifa, Israel

The aim of this chapter is to cover the objectives, challenges, and implementation of closed‐loop active flow control for unmanned aerial vehicles (UAVs). First, fundamental concepts of control theory are introduced. Later, the focus is on the experimental evaluation of closed‐loop control to modify the natural flow behavior; in other words to increase aerodynamic performance. We will cover the historical development of and recent activity in the field, with emphasis on experimental implementation of open‐ and closed‐loop control approaches. To realize the practical implementation, one first needs to achieve control authority in the open loop. Therefore, various scaling parameters are considered and discussed. In addition to describing successes, failures, and outstanding issues relevant to UAVs, we will highlight the characteristics of the various actuators, the flow sensing and measurement, and the methodologies employed to date in free‐flight in order to emphasize the choices, challenges, and potential of flow control for unmanned aerial vehicles.

13.1 Introduction

Unmanned aerial vehicles (UAVs) are becoming smaller and lighter, and thus more sensitive to external disturbances, such as gusts. At the same time, low‐Reynolds‐number flight, associated with UAVs, presents numerous challenges because of the susceptibility ...