MSc.Thesis Defense: Ahmet Faruk Günalp

A Novel Approach to the Rendezvous Problem for Aerial Refueling of Multi-UAV Systems

Ahmet Faruk Günalp

Mechatronics Engineering, MSc. Thesis, 2025

Thesis Jury

Prof. Dr. Mustafa Ünel (Thesis Advisor),

Asst. Prof. Dr. Melih Türkseven, Asst. Prof. Dr. Abdurrahman Eray Baran

Date & Time: 27th June, 2025 – 10.30 AM

Place: FENS G029

Keywords: Aerial Refueling, Rendezvous Problem, Formation Control, Distributed Control, Multi-UAV Systems

Abstract

Advancements in unmanned aerial vehicle (UAV) technology have led to their widespread adoption in both industry and academia. In recent years, the increasing focus on multi-agent systems has brought UAVs further into the spotlight. Multiple UAVs can perform tasks that are beyond the capabilities of a single vehicle or execute shared missions with enhanced efficiency and effectiveness. Aerial refueling, a strategic and long-established procedure in both civil and military aviation, significantly extends the range and operational capabilities of aerial vehicles. Recent research has explored automating this process for both manned and unmanned aircraft; however, current efforts primarily address single-vehicle scenarios. Given the growing use of UAV swarms in applications such as search and rescue, terrain map ping, and disaster relief, autonomous aerial refueling for multiple UAVs represents a logical and necessary next step. This thesis addresses the rendezvous problem for multiple UAVs approaching a tanker aircraft. Reference trajectories are generated using virtual spring-damper and charged particle models. A distributed control architecture is designed, employing waypoint-following controllers for individual vehicles. In 2D proof-of-concept scenarios, non-holonomic UGVs are utilized, and their motion control is achieved via cascaded controllers which utilize virtual inputs. Additionally, a novel collision avoidance algorithm and a two-phase docking procedure are proposed. To validate the proposed framework, a series of coordinated task scenarios involving groups of UGVs and UAVs are simulated in both 2D and 3D environments. The results confirm the effectiveness of the coordination strategy and formation control, demonstrating robust and satisfactory performance across a variety of scenarios.